WO2016151675A1 - Living body observation device and living body observation method - Google Patents

Abstract

The purpose of the present invention is to detect fat stably while maintaining smooth observation in the case where the amount of blood placed on the fat is small and while improving the accuracy of the detection of blood when blood is placed on the fat. A living body observation device (1) equipped with a light source section (3) for irradiating a biological tissue with illuminating light, an imaging section (11) for imaging reflected light in the biological tissue to acquire an image, a fat detection section for detecting fat in the acquired image, a blood detection section for detecting blood in the image, and a control section (16) for controlling the light source section (3) and/or the imaging section (11) on the basis of the detection results obtained by the fat detection section and the blood detection section, wherein the control section (16) makes it possible to switch between a simultaneous-type first imaging mode in which multiple light beams having different wavelength bands from each other are imaged simultaneously and a frame sequential-type second imaging mode in which the light beams are imaged sequentially, depending on the condition of blood detected in the image by the blood detection section when fat is detected in the image by the fat detection section.

Description

Living body observation apparatus and living body observation method

The present invention relates to a living body observation apparatus and a living body observation method.

A narrow band light observation (NBI) is known, which illuminates illumination light of a narrow band which is easily absorbed by hemoglobin contained in blood and highlights capillaries and the like on the surface of the mucous membrane (for example, Patent Document 1) reference.).
This narrow-band light observation is expected as an alternative observation method of pigment dispersion widely performed for detailed diagnosis of the esophagus region and pit pattern (ductal structure) observation of the large intestine, and the examination time and unnecessary biopsy The reduction is expected to contribute to the efficiency of inspections.

However, although narrowband light observation can highlight blood vessels, it is difficult to highlight nerves. For example, in the case of nerve preservation in total rectum excision surgery or total prostate excision surgery, when removing the target organ, expose the target organ so as not to damage the nerve distributed so as to surround the target organ. Although it is necessary to remove it, thin nerves with a diameter of 50 to 300 μm are white or transparent, so it is difficult to observe even by a laparoscopic magnifying observation. For this reason, there is a disadvantage that the doctor has to operate according to experience and intuition and there is a high possibility of damage.

For this reason, there has been proposed a living body observation apparatus capable of preventing damage to nerves surrounding a target organ by making the structure of the tissue on the surface of the target organ such as an extraction target easy to see (for example, patent documents 2). According to this living body observation apparatus, focusing on the fact that the nerve surrounding the target organ is present in the fat layer, the absorption characteristics of β-carotene contained in fat and hemoglobin in the blood have different wavelength bands. Because of the absorption characteristics, it is possible to irradiate the irradiation light of the corresponding wavelength band to obtain an image that is easy to identify fat, and to perform surgery so as not to damage nerves distributed in the fat layer.

The detection of fat is performed by extracting the difference between the image captured by irradiating the light near 480 nm with much absorption of β-carotene and the light imaged by the light near 510 nm with little absorption of β-carotene and extracted. realizable. By the way, blood is present on the subject due to bleeding during the operation. Hemoglobin contained in blood has absorption characteristics in the wavelength band near 480 nm and 510 nm, so absorption of hemoglobin becomes dominant compared to the absorption of β-carotene when a large amount of blood is placed on fat , Fat can not be detected accurately (false positive, false negative occurs).

For this reason, blood is detected by comparing an image captured by irradiation with light near 610 nm having a small absorption of hemoglobin with an image captured by irradiation with light near 510 nm having a larger absorption than 610 nm to detect blood as described above. It is desirable to correct fat detection results with blood detection results.

JP 2011-224038 A International Publication No. 2013/115323

As a characteristic of light in living organisms, light with a long wavelength has a characteristic of reaching deeper layers of living organisms. Therefore, in the image captured by the light whose wavelength is separated, the obtained information is different in the depth direction of the living body. That is, since the image captured by emitting light in the vicinity of 510 nm and the image captured by emitting light in the vicinity of 610 nm are different in the information in the depth direction, blood detection accuracy is lowered, and stable fat detection can not be performed.

The present invention has been made in view of the above-described circumstances, and improves the detection accuracy of blood when blood is placed on fat while maintaining smooth observation when there is little blood on fat. However, it is an object of the present invention to provide a living body observing apparatus and a living body observing method capable of performing stable fat detection.

One embodiment of the present invention includes a light source unit that emits illumination light to a living tissue, an imaging unit that captures reflected light from the living tissue of the illumination light emitted by the light source unit and acquires an image, and the imaging unit Based on a fat detection unit that detects fat in the acquired image, a blood detection unit that detects blood in the image acquired by the imaging unit, and detection results by the fat detection unit and the blood detection unit Control unit configured to control at least one of the light source unit and the imaging unit, the control unit controlling the image by the blood detection unit in a state where fat is detected in the image by the fat detection unit A living body that switches between a simultaneous first imaging method for simultaneously imaging a plurality of band lights of different wavelength bands and a second imaging method for surface sequential imaging that sequentially images according to the state of blood detected inside Observation equipment It is.

According to this aspect, when the illumination light emitted from the light source unit is irradiated to the living tissue, and the reflected light in the living tissue is photographed by the imaging unit and an image is acquired, the fat detection unit is acquired using the acquired image As a result, fat in the image is detected, and blood in the image is detected by the blood detection unit. In a state where fat is detected in the image by the fat detection unit, when the state of the blood detected in the image by the blood detection unit changes, the control unit performs the first imaging method and the second imaging method Switch.

In the first imaging method, since plural bands of light having different wavelength bands are simultaneously irradiated, reflected light of plural bands of light can be photographed at the same time, and the frame rate can be improved. On the other hand, in the second imaging method, since a plurality of band lights of different wavelength bands are sequentially irradiated, the frame rate is lower than that of the first imaging method, but reflected light of extremely close wavelength bands which can not be captured simultaneously. Can take pictures.

Since β-carotene and hemoglobin contained in living tissue vary in absorbance depending on the wavelength, it is possible to easily detect the amount of β-carotene and hemoglobin contained in living tissue by acquiring reflected light of different wavelengths and taking the ratio. it can. Beta-carotene is effective in detecting fat because it is abundant in fat, and hemoglobin is effective in detecting blood because it is rich in blood.

In this case, since biological tissue has wavelength-dependent scattering characteristics, it is possible to capture reflected light that is scattered and returned at different depth positions due to the difference in the degree of penetration to the biological tissue when the wavelengths are separated. Become. Therefore, in the second imaging method, by capturing reflected light in a close wavelength band, components contained in living tissue are accurately detected using light of different wavelengths returning from the equivalent depth position. be able to.

In the above aspect, in the first imaging method, the blood detection unit is a hemoglobin based on a ratio between an image signal of a green wavelength band and an image signal of a red wavelength band simultaneously acquired by the imaging unit. In the second imaging method, hemoglobin may be detected based on a ratio of image signals of two wavelength bands of green having difference in absorbance of hemoglobin sequentially acquired by the imaging unit.

The light in the green wavelength band and the red wavelength band both have low absorbance to β-carotene, and the light in the green wavelength band has higher absorbance to hemoglobin than the light in the red wavelength band. Therefore, in the first imaging method, hemoglobin can be detected by taking these ratios. In this case, since light in the red and green wavelength bands is easily separated and photographed, it can be photographed at the same time, and the frame rate can be improved.

In addition, light of two green wavelength bands having differences in absorbance for hemoglobin used in the second imaging method also detects hemoglobin by taking the ratio because absorbance for β-carotene is similarly low. be able to. In this case, since it is difficult to separate and shoot the light in the two green wavelength bands, it is necessary to sequentially capture them, and the frame rate is lowered, but the reflected light is scattered and returned at the same depth position. Therefore, hemoglobin can be detected accurately.

In the above aspect, the green wavelength band in the first imaging system is a wavelength band near 510 nm, the red wavelength band is a wavelength band near 610 nm, and the green in the second imaging system The wavelength band of may be a wavelength band near a wavelength of 510 nm and a wavelength near a wavelength of 540 nm.

In this way, in the first imaging method, the absorption characteristics of β-carotene are low and the absorption characteristics of hemoglobin are relatively high, and the light of wavelength bands around 510 nm and the absorption characteristics of β-carotene and hemoglobin are both low. Light in a wavelength band near 610 nm can be simultaneously captured to detect the amount of hemoglobin at a high frame rate without being affected by β-carotene.

On the other hand, in the second imaging method, since the light of the wavelength band of 510 nm and the light of 540 nm near which the absorption characteristic of hemoglobin is higher than the light of the wavelength band of 510 nm are sequentially photographed, the frame rate is the first photographing. Hemoglobin can be detected with high accuracy based on the information of the same depth position although it is lower than the method.

In the above aspect, the blood detection unit detects the spread of blood in the image acquired by the imaging unit, and the control unit determines that the spread of blood detected by the blood detection unit is predetermined. When the threshold value is exceeded, the second imaging method may be switched.
By doing this, when the spread of the blood is small, the smooth imaging of the movement at a high frame rate is performed by the first imaging method, and when the spread of the blood becomes large, the second imaging is performed. By switching to the method, it is possible to detect blood accurately and detect fat with less influence of blood.

Further, in the above aspect, the image processing apparatus further includes a motion detection unit that detects an amount of motion of the imaging unit with respect to the living tissue based on the image acquired by the imaging unit, and the control unit detects the movement by the motion detection unit. If the calculated motion amount is smaller than a predetermined threshold, switching to the second imaging method may be performed.
In this way, in a state where the imaging unit is moved with respect to the living tissue to move the observation position, movement of the first imaging method with high frame rate can be smooth even if blood spreading is occurring. Image observation, and in the state where the imaging unit is at rest with respect to the living tissue, when blood spreading occurs, fat detection with reduced influence of blood by the second imaging method is performed. Can.

Further, in the above aspect, the motion detection unit may identify a global motion vector of the entire image and a local motion vector, and detect a motion amount based on the global motion vector. .
By doing this, even if there is a local image movement in which a treatment tool such as forceps moves in a still image, the amount of movement is as long as there is no global motion vector for the entire image. The observation by the second imaging method can be performed as a small one.

In the above-mentioned mode, it has a mist detection part which detects existence of generation of mist based on the above-mentioned picture, and when the control part detects that mist has disappeared by the mist detection part, You may switch to the said 2nd imaging | photography method.
In this way, when the mist detection unit detects that mist is generated in the image, the field of view is poor due to the mist and it is difficult to detect with high accuracy, so the first photographing is performed. Switch to the method, and perform observation with a smooth image of movement with a high frame rate. On the other hand, when the mist disappears, the visual field is improved, and therefore, when the spread of the blood is large, fat can be detected with the influence of the blood suppressed by the second imaging method.

Further, another aspect of the present invention is an illumination step of irradiating illumination light to a living tissue, an imaging step of capturing reflected light of the illumination light emitted by the illumination step in the living tissue, and acquiring an image; The fat is detected in the image obtained in the imaging step, the fat detecting step for detecting fat in the image, the blood detecting step for detecting blood in the image obtained in the imaging step, and the fat in the image obtained by the fat detecting step In the detected state, according to the state of the blood detected in the image by the blood detection step, a simultaneous imaging method for simultaneously imaging a plurality of band lights having different wavelength bands and a plane sequential imaging sequentially It is a living body observation method including the control step which changes with the photography method of a formula.

According to the present invention, it is possible to accurately detect a blood vessel present in a living tissue and to selectively detect a blood vessel having a predetermined thickness.

BRIEF DESCRIPTION OF THE DRAWINGS It is a whole block diagram which shows the biological body observation apparatus which concerns on the 1st Embodiment of this invention. It is a figure which shows the spectral characteristic of (beta) carotene and hemoglobin which are detected by the biological body observation apparatus of FIG. It is a figure which shows the timing chart explaining the 1st imaging | photography method by the biological body observation apparatus of FIG. It is a figure which shows the timing chart explaining the 2nd imaging | photography system by the biological body observation apparatus of FIG. It is a block diagram which shows the image processing part with which the biological body observation apparatus of FIG. 1 is equipped. It is a figure explaining the detection of the spreading | spread of the blood on the image acquired by the biological body observation apparatus of FIG. It is a figure which shows the flowchart explaining the biological body observation method by the biological body observation apparatus of FIG. It is a whole block diagram which shows the modification of the biological body observation apparatus of FIG. It is a front view which shows the filter turret with which the biological body observation apparatus of FIG. 8 is equipped. It is a block diagram showing the image processing device with which the living body observation device concerning a 2nd embodiment of the present invention is equipped. It is a block diagram which shows the movement amount detection part with which the biological body observation apparatus of FIG. 10 is equipped. It is a figure which shows an example of the motion vector calculated by the motion amount detection part of FIG. It is a figure which shows the flowchart explaining the biological body observation method by the biological body observation apparatus of FIG. It is a block diagram which shows the image processing apparatus with which the biological body observation apparatus which concerns on the 3rd Embodiment of this invention is equipped. It is a figure which shows the flowchart explaining the biological body observation method by the biological body observation apparatus of FIG. It is a figure which shows the time change of the evaluation value of average brightness and brightness | luminance until mist generate | occur | produces in a body and lose | disappears. It is a figure which shows the time change of the evaluation value of average saturation and saturation until the mist generate | occur | produces in a body and lose | disappears. It is a figure which shows the time change of the evaluation value of the average D range and D range until mist generate | occur | produces in a body and lose | disappears.

A living body observation apparatus 1 and a living body observation method according to a first embodiment of the present invention will be described below with reference to the drawings.
The living body observation apparatus 1 according to the present embodiment is an endoscope apparatus, and as shown in FIG. 1, an insertion unit 2 inserted into a living body, a light source unit 3 connected to the insertion unit 2, and A main unit 5 including a signal processing unit 4 and an image display unit 6 displaying an image generated by the signal processing unit 4 are provided.

The insertion unit 2 includes an illumination optical system 7 for irradiating the light input from the light source unit 3 toward the subject, and a photographing optical system 8 for photographing reflected light from the subject. The illumination optical system 7 is disposed over the entire length of the insertion portion 2, and the light guide cable 9a for guiding the light incident from the light source portion 3 on the proximal end to the tip 2a and the tip of the insertion portion 2 And a diffusion optical system 9b for emitting light from the front to the front. The photographing optical system 8 includes an objective lens 10 for condensing reflected light of the light irradiated by the illumination optical system 7 in the biological tissue, and an imaging element (imaging unit) 11 for photographing the light condensed by the objective lens 10. Is equipped. The imaging device 11 is a color CCD provided with a filter that transmits blue, green, and red light to each pixel.

The light source unit 3 includes a plurality of light emitting diodes (LEDs) L1, L2, L3, L4 for emitting light of different wavelength bands, a mirror 12 and a dichroic mirror 13, and light from the respective light emitting diodes L1, L2, L3, L4 To be incident on the incident end of the light guide cable 9a.
In the example shown in FIG. 1, the blue wavelength band near 480 nm (hereinafter referred to as B wavelength), the green wavelength band near 510 nm (hereinafter referred to as G1 wavelength), and near 540 nm (hereinafter referred to as G2 wavelength). And four light emitting diodes L1, L2, L3, and L4 that respectively emit light in a wavelength band of 610 nm (hereinafter referred to as R wavelength), which is a red wavelength band.

As shown in FIG. 2, β-carotene contained in fat has an absorption characteristic that is high at the B wavelength and low absorbance at the G1 wavelength, the G2 wavelength, and the R wavelength. In addition, hemoglobin (HbO ₂ ), which is a component in blood, has a low absorption characteristic at the R wavelength and a higher absorption characteristic than the R wavelength at the G1 wavelength and the G2 wavelength. Hemoglobin has a higher absorption characteristic at the G2 wavelength than at the G1 wavelength.

The signal processing unit 4 includes a memory 14 for storing an image signal acquired by the imaging device 11, an image processing unit 15 for performing predetermined image processing on the image signal stored in the memory 14, light emitting diodes L1 and L2, and A control unit 16 is provided to control the light emission timing of L 3 and L 4 and the imaging timing synchronization by the imaging device 11 and the write and read timing of the memory 14.

Here, the relationship between the imaging timing of the imaging device 11, the light emission timings of the light emitting diodes L1, L2, L3 and L4, and the write and read timings of the memory 14 will be described with reference to FIGS. 3 and 4. As shown in FIGS. 3 and 4, the control unit 16 can switch between two imaging methods.

In the first imaging method, as shown in FIG. 3, the light emitting diodes L1, L2, and L4 in the light source unit 3 are controlled to synchronize with the period T required for imaging of the imaging element 11, and the B and G wavelengths And R wavelength light is emitted. At this time, the light emitting diode L3 does not emit light, and light of G2 wavelength is not emitted.

Therefore, in the first imaging method, from the light source unit 3, light of B wavelength having high absorbance of β-carotene, light of G wavelength having low absorbance of β-carotene and high absorbance of hemoglobin, β-carotene and hemoglobin Light of R wavelength with low absorbance is emitted. The light of three wavelengths emitted from the light source unit 3 is irradiated to the living tissue via the light guide cable 9 a and the diffusion optical system 9 b in the insertion unit 2, and the reflected light of the light in the living tissue is the imaging optical system 8. The light is collected by the objective lens 10 of the image pickup device 11 and simultaneously photographed by the image pickup device 11.

An image acquired by imaging in one period T is written to the memory 14 each time, read out at the next imaging timing, and sent to the image processing unit 15 in the subsequent stage. For example, after an image acquired by the imaging device 11 is written to the memory 14, it is read at timing when the imaging device 11 acquires the next image. Details of image processing by the image processing unit 15 will be described later.

In the second imaging method, as shown in FIG. 4, the light emitting diodes L1, L2, L3, and L4 in the light source unit 3 are controlled to synchronize with the first period Ta required for imaging of the imaging device 11B. The light of the wavelength, the G1 wavelength and the R wavelength is emitted, and the emission of the light of the B wavelength, the G2 wavelength and the R wavelength is alternately repeated in synchronization with the next second period Tb.

Therefore, in the second imaging method, the light source unit 3 emits light of B wavelength having high absorbance of β-carotene during the first period Ta and light of G wavelength having low absorbance of β-carotene and high absorbance of hemoglobin. , And light of R wavelength with low absorbance of both β-carotene and hemoglobin. Also, from the light source unit 3, light of B wavelength having high absorbance of β-carotene, light of G wavelength having low absorbance of β-carotene and high absorbance of hemoglobin, and light absorbance of β-carotene and hemoglobin during the second period Tb Both low R wavelength light is emitted. The light of three wavelengths emitted from the light source unit 3 in the first period Ta and the second period Tb is applied to the living tissue through the light guide cable 9a and the diffusion optical system 9b in the insertion portion 2, Reflected light of light in the living tissue is collected by the objective lens 10 of the photographing optical system 8 and is alternately photographed by the imaging element 11.

The image acquired by the imaging in the first period Ta is written to the memory 14 and read out during the next second period Tb and the period (Ta + Tb) until the imaging end of the next first period Ta, and the subsequent stage Is sent to the image processing unit 15 of FIG. After the image acquired by the imaging in the second period Tb is written to the memory 14, the reading is immediately started and is read out in the period (Ta + Tb) until the end of the imaging of the next first period Ta. It is sent to the image processing unit 15 in the latter stage.

For example, after an image acquired in the first period Ta by the imaging device 11 is written to the memory 14, it is read at timing when the imaging device 11 acquires a next image Tb. Further, the image acquired in the second period Tb by the imaging device 11 is read out at the same timing as the image acquired in the first period Ta immediately after being written in the memory 14 and the image processing unit in the subsequent stage It will be sent to 15.

As shown in FIG. 5, the image processing unit 15 includes a preprocessing unit 17, a β-carotene detection unit (fat detection unit) 18, a hemoglobin detection unit (blood detection unit) 19, a fat extraction unit 20, and a blood distribution calculation unit 21. , A post-processing unit 22 and a fat emphasizing unit 23.
The preprocessing unit 17 is configured to perform OB (optical black) clamp processing, gain correction processing, and WB (white balance) correction processing on the image signal transferred from the memory 14. The pre-processing unit 17 is configured to output the pre-processed image signal to the post-processing unit 22, the β-carotene detection unit 18, and the hemoglobin detection unit 19.

The β-carotene detection unit 18 detects β-carotene by calculating the ratio of the signal value of the B wavelength to the signal value of the G1 wavelength in the image signal sent from the pre-processing unit 17, and outputs it as a β-carotene detection value It is supposed to
In the first imaging method, the hemoglobin detection unit 19 detects the hemoglobin by calculating the ratio of the signal value of the G1 wavelength to the signal value of the R wavelength in the image signal sent from the preprocessing unit 17, It is output as a hemoglobin detection value.
In the second imaging method, the hemoglobin detection unit 19 detects hemoglobin by calculating the ratio of the signal value of the G1 wavelength to the signal value of the G2 wavelength in the image signal sent from the preprocessing unit 17 And output as a hemoglobin detection value.

In the first imaging method, the fat extraction unit 20 previously obtains a coefficient K1 represented by the following equation (1) based on the absorption characteristics of hemoglobin in order to perform fat extraction in which the influence of blood is removed. Here, μ (λi) is the absorbance of light at the wavelength λi, and λ1 = B wavelength, λ2 = G1 wavelength, λ4 = R wavelength. Furthermore, as shown by the following equation (2), the fat extraction unit 20 detects the β-carotene detection value CrValue output from the β-carotene detection unit 18, the hemoglobin detection value HbValue1 output from the hemoglobin detection unit 19, and the coefficient K1. From this, the fat extraction value BkValue1 is calculated.

K1 = (μ (λ1) -μ (λ2)) / (μ (λ4) -μ (λ2)) (1)
BkValue1 = CrValue / HbValue1 ^K1 (2)

On the other hand, in the second imaging method, the fat extraction unit 20 previously obtains a coefficient K2 represented by the following equation (3) based on the absorption characteristic of hemoglobin in order to perform fat extraction in which the influence of blood is removed. . Here, μ (λi) is the absorbance of light at the wavelength λi, where λ1 = B wavelength, λ2 = G1 wavelength, λ3 = G2 wavelength. Furthermore, as shown by the following equation (4), the fat extraction unit 20 detects the β-carotene detection value CrValue output from the β-carotene detection unit 18, the hemoglobin detection value HbValue2 output from the hemoglobin detection unit 19, and the coefficient K2 From this, the fat extraction value BkValue2 is calculated.

K2 = (μ (λ1) -μ (λ2)) / (μ (λ3) -μ (λ2)) (3)
BkValue2 = CrValue / HbValue2 ^K2 (4)

The post-processing unit 22 is configured to perform tone conversion processing, color processing, and edge enhancement processing on the image signal sent from the pre-processing unit 17. The post-processing unit 22 is configured to output the post-processed image signal to the fat emphasizing unit 23.
The fat emphasizing unit 23 performs color emphasis on the image signal input from the post-processing unit 22 based on the fat extraction value extracted by the fat extracting unit 20, and outputs the image signal to the image display unit 6. .

Next, the blood distribution calculation unit 21 will be described.
The operation of the blood distribution calculation unit 21 is common to the first imaging method and the second imaging method.
As shown in FIG. 6, the blood distribution calculating unit 21 sets a target region for calculating the blood distribution at the center of the image at which the operator gazes, in order to calculate the blood distribution on the image. The area is divided into a plurality of blocks.

In FIG. 6, the target area is divided into 24 blocks. Then, the average value of the detected hemoglobin values in each block is calculated, and it is determined that the block whose average value is larger than a predetermined threshold is that the blood is spread. When the number of blocks determined to have blood spread exceeds a predetermined number, it is determined that the blood spread on the image is large, and the control unit 16 is notified of this.

A living body observation method using the living body observation device 1 according to the present embodiment configured as described above will be described below.
In the living body observation method according to the present embodiment, as shown in FIG. 7, an illumination step S2 for irradiating illumination light to a living tissue, and an imaging step S3 for capturing an image by capturing reflected light reflected on the living tissue. The fat detection step S4 for detecting fat in the image, the blood detection step S5 for detecting blood in the image, and the fat detection step at the fat detection step S4 A state is detected (step S6), and control steps S7, S8, and S9 for switching between the first imaging method and the second imaging method according to the detected blood state are included.

More specifically, the operator inserts the insertion portion 2 into the living body, and with the tip 2a of the insertion portion 2 facing the living tissue in the body, the illumination light emitted from the light source unit 3 is a living tissue And the reflected light from the living tissue is photographed by the imaging device 11. In the initial state, the control unit 16 first controls the light source unit 3, the imaging device 11, the memory 14, and the image processing unit 15 according to the first imaging method (step S1).

That is, the control unit 16 controls the light emitting diodes L1, L2, and L4 in the light source unit 3 to emit light of the B wavelength, the G1 wavelength, and the R wavelength in synchronization with the period required for imaging of the imaging device 11. . At this time, light of the G2 wavelength is not emitted.

As a result, from the light source unit 3, light of B wavelength having high absorption characteristics of β-carotene, absorption light of G-wavelength having low absorption characteristics of β-carotene and high absorption characteristics of hemoglobin, as well as absorption characteristics of β-carotene and hemoglobin Light with a low R wavelength is emitted. The light of three wavelengths emitted from the light source unit 3 is irradiated to the living tissue via the light guide cable 9a and the diffusion optical system 9b in the insertion unit 2 (illumination step S2), and the reflected light of the light in the living tissue is The light is collected by the objective lens 10 of the photographing optical system 8. The control unit 16 controls the imaging timing of the imaging element 11 to simultaneously capture these reflected lights (imaging step S3).

The control unit 16 writes the image acquired by photographing in one period into the memory 14 each time, reads it at the next photographing timing, and causes the image processing unit 15 to output it.
In the image processing unit 15, first, the preprocessing unit 17 subjects the image signal transferred from the memory 14 to preprocessing such as OB clamp processing, gain correction processing, WB correction processing, etc. The image signal is output to the post-processing unit 22, the β-carotene detection unit 18 and the hemoglobin detection unit 19.

In the post-processing unit 22, tone conversion processing, color processing and edge enhancement processing are performed on the image signal sent from the pre-processing unit 17.
The β-carotene detection unit 18 detects β-carotene by calculating the ratio of the signal value of the B wavelength of the image signal sent from the pre-processing unit 17 to the signal value of the G1 wavelength (fat detection step) S4).
In the hemoglobin detection unit 19, the hemoglobin is detected by calculating the ratio between the signal value of the G1 wavelength and the signal value of the R wavelength in the image signal sent from the pre-processing unit 17 (blood detection step S5) .

The β-carotene detection value detected by the β-carotene detection unit 18 and the hemoglobin detection value detected by the hemoglobin detection unit 19 are sent to the fat extraction unit 20 and are based on the absorption characteristics of hemoglobin at B, G1 and R wavelengths. The fat extraction value is calculated using a coefficient K1 which has been obtained in advance.
Then, the fat emphasizing unit 23 performs color emphasis on the image signal input from the post-processing unit 22 based on the fat extraction value extracted by the fat extracting unit 20, and the image in which fat is emphasized is an image display unit Displayed on 6.

Thus, the operator can easily identify the region where fat is present by confirming the image displayed on the image display unit 6, and surgery is performed so as not to damage the nerve distributed in the fat layer. It can be performed.
Here, the display frame rate of the image in the first imaging method is 1 / T.

In this case, in the image processing unit 15, the hemoglobin detection value detected by the hemoglobin detection unit 19 is sent to the blood distribution calculation unit 21, and the spread of blood in the central region of the image is calculated (step S6). If it is determined that the spread of the upper blood is large, the control unit 16 is notified (step S7).
When the notification that the spread of the blood calculated by the blood distribution calculation unit 21 is large is sent to the control unit 16, the control unit 16 switches from the first imaging method to the second imaging method (step S9). .

When the second imaging method is switched, it is determined whether the imaging can be continued (step S10), and when the imaging is continued, the control unit 16 controls the light emitting diodes L1, L2, L3, and L4 in the light source unit 3. The light of the B wavelength, the G1 wavelength and the R wavelength is emitted in synchronization with the first period required for photographing of the imaging device 11 by control, and the B wavelength, the G2 wavelength and R are synchronized with the next second period. The light emission of the wavelength is alternately repeated.

Thus, from the light source unit 3, light of B wavelength having high absorption characteristics of β-carotene during the first period, light of G1 wavelength having low absorption characteristics of β-carotene and high absorption characteristics of hemoglobin, β-carotene and hemoglobin And R light having low absorption characteristics are emitted. Also, from the light source unit 3, light of wavelength B having high absorption characteristics of β-carotene in the second period, light of wavelength G2 having low absorption characteristics of β-carotene and high absorption characteristics of hemoglobin, β-carotene and hemoglobin Light of R wavelength with low absorption characteristics is emitted.

Light of three wavelengths emitted from the light source unit 3 in the first period and the second period is applied to the living tissue via the light guide cable 9 a and the diffusion optical system 9 b in the insertion portion 2 (illumination step S2) Reflected light of light in the living tissue is collected by the objective lens 10 of the photographing optical system 8 and photographed alternately by the imaging element 11 (imaging step S3).

An image acquired by shooting in the first period is written to the memory 14 and read out and sent to the image processing unit 15 in the next second period and the period until the end of shooting in the next first period. . After the image acquired by the imaging in the second period is written to the memory 14, the reading is immediately started, and is read out in the period until the end of the imaging in the next first period, and the image processing unit 15 Sent. Here, the display frame rate of the image in the second imaging method is 1 / 2T.

The image processing unit 15 performs pre-processing, post-processing and β-carotene detection processing on the image signal read from the memory 14 in the same manner as the first imaging method (fat detection step S4).
On the other hand, the hemoglobin detection unit 19 detects the hemoglobin by calculating the ratio between the signal value of the G1 wavelength and the signal value of the G2 wavelength in the image signal sent from the preprocessing unit 17 (blood detection step S5 ), Is output as a hemoglobin detection value.

In addition, in the fat extraction unit 20, in order to perform fat extraction in which the influence of blood is removed, fat extraction is performed using a coefficient K2 obtained in advance based on the absorption characteristics of hemoglobin at the B wavelength, G1 wavelength, and G2 wavelength. The value is calculated.
Then, in the fat emphasizing unit 23, color emphasis of the image signal input from the post-processing unit 22 is performed based on the fat extraction value extracted by the fat extracting unit 20, and output to the image display unit 6.

On the other hand, when the transmission of the notification is stopped from the state where the notification that the blood spread (step S6) calculated by the blood distribution calculation unit 21 is large is sent (step S7), the control unit 16 performs the second imaging. The mode is switched to the first imaging mode (step S8).
As described above, in the first imaging method, the hemoglobin detection unit 19 detects hemoglobin based on the ratio of the signal value of the G1 wavelength to the signal value of the R wavelength.

Thus, according to the living body observation apparatus 1 and the living body observation method according to the present embodiment, when it is determined that the distribution of blood has spread on the image, the transition from the first imaging method to the second imaging method is made. By doing this, instead of the display frame rate decreasing from 1 / T to 1 / 2T, detection of hemoglobin is performed by the ratio of the signal value of the G1 wavelength to the signal value of the G2 wavelength.

The difference in absorption of hemoglobin is remarkable between the light of the G1 wavelength and the light of the G2 wavelength, and since the light of the wavelength which is very close, information from approximately the same position in the depth direction of the living tissue is It contains. As a result, the detection accuracy of blood detected by hemoglobin detected using reflected light of these wavelengths can be improved, and there is an advantage that fat detection with less influence of blood can be performed.

On the other hand, when it is determined that the blood distribution has become smaller on the image, the ratio of the signal value of the G1 wavelength to the signal value of the R wavelength is obtained by transitioning from the second imaging method to the first imaging method. Causes the display frame rate to be improved from 1⁄2T to 1 / T instead of the detection of hemoglobin.

That is, the light of the G1 wavelength and the light of the R wavelength have a remarkable difference in absorption of hemoglobin, but when compared with the relationship between the G1 wavelength and the G2 wavelength, the wavelengths are distant, so the depth direction of the living tissue Contains information from different locations. As a result, the detection accuracy of blood by hemoglobin detected using the reflected light of these wavelengths is lower than in the case of the second imaging method, but the frame rate is improved instead and the movement is smooth. There is an advantage that an easy-to-see image can be displayed.

In the present embodiment, the blood distribution calculation unit 21 calculates the blood distribution in the target area at the center of the image that the operator is considered to be gazing at, but instead, it is possible to use fat other than the center of the image. An area having a high extraction value may be detected, and the area may be set as a target area. Also, an arbitrary area may be set as the target area by the operator.

Further, the blood distribution calculation unit 21 stores the average value of the detected hemoglobin values in a storage unit (not shown) for each imaging frame, and calculates the time change of the average value to detect the presence or absence of hemorrhage, and bleeding is present. The spread of blood may be determined from the number of blocks. By doing this, even in the case where a thick blood vessel is present in the target region for which the blood distribution is to be calculated, it is possible to detect the spread of hemorrhage in distinction from the thick blood vessel.

Further, in the present embodiment, the light source unit 3 configured to emit light of different wavelength bands is configured by the plurality of light emitting diodes L1, L2, L3, and L4. However, instead of this, as shown in FIG. A light source unit 27 having a xenon lamp 24 for generating light, a filter turret 25 for rotating a plurality of narrow band filters F1, F2 and F3, and a linear movement mechanism 26 for moving the filter turret 25 in a radial direction You may

As shown in FIG. 9, the filter turret 25 includes a narrow band filter F1 disposed radially inward and narrow band filters F2 and F3 disposed radially outward. The narrow band filters F1 and F2 transmit the B wavelength, the G1 wavelength, and the R wavelength, and the filter F3 transmits the B wavelength, the G2 wavelength, and the R wavelength. A narrow band-pass filter F1 is disposed on the optical axis from the xenon lamp 24 to the light guide cable 9a, and the filter turret 25 is rotated to perform the illumination of the first imaging method, and the narrow band-pass filter F2 on the optical axis , F3 and rotating the filter turret 25, illumination of the second imaging method can be performed.

In the embodiment, the narrow band light is generated in the light source unit 3 and the reflected light in the living body tissue is photographed as it is, but instead, the living body tissue is irradiated with wide band light such as white light. Alternatively, a filter that selectively transmits narrow band light may be disposed upstream of the imaging element 11 of the imaging optical system 8. As the filter, a filter using the above-described filter turret 25 or a wavelength tunable filter such as an etalon may be employed.

Next, a living body observation apparatus according to a second embodiment of the present invention will be described below with reference to the drawings.
In the description of the present embodiment, parts having the same configuration as those of the living body observation apparatus 1 according to the first embodiment described above are assigned the same reference numerals and descriptions thereof will be omitted.

In the living body observation apparatus according to the present embodiment, as shown in FIG. 10, a motion amount detection unit (motion detection unit) 29 that calculates the motion amount of an image based on the image signal after the image processing unit 30 is processed. And the control unit 16 switches to the second imaging method when the spread of the blood is large and the movement amount of the image detected by the movement amount detection unit 29 is smaller than a predetermined threshold. This is different from the living body observation device 1 according to the first embodiment.

For example, as shown in FIG. 11, the motion amount detection unit 29 is sent from the pre-processing unit 17 and a memory 31 that delays the image signal of G wavelength sent from the pre-processing unit 17 by one frame. A motion vector calculation unit 32 that calculates a motion vector from the G wavelength image signal and the G wavelength image signal stored in the memory 31 that has been stored in the memory 31, and intersects the optical axis based on the calculated motion vector And a motion amount calculation unit 33 for calculating the motion amount in the direction to be moved.

The motion vector can be calculated by a known block matching method or gradient method. Here, motion vectors are calculated for a plurality of points set at equal intervals on the image, as shown in FIG.
The motion amount calculator 33 is configured to calculate the motion amount MV by the following equation (5) based on the motion vector calculated by the motion vector calculator 32.

Here, M is the total number of motion vectors, and vi is a motion vector.
As shown in FIG. 13, the global motion of the entire image can be calculated as the motion amount of the image by calculating the motion amount by averaging all the motion vectors (step S11).

By doing this, when the amount of movement of the image is large, that is, when the imaging optical system 8 at the tip 2a of the insertion portion 2 is moving, the operator is not in the state of performing detailed treatment. , It is thought that it is in the state where it is looking for a bleeding place or an affected part. Therefore, even when it is determined by the blood distribution calculation unit 21 that the spread of the blood is large, the first imaging method can be maintained, and a decrease in the display frame rate can be prevented (step S12). On the other hand, when it is determined by the blood distribution calculation unit 21 that the spread of the blood is large and the amount of movement of the image is small, that is, when the photographing optical system 8 of the tip 2a of the insertion unit 2 is stationary. Can be switched to the second imaging method, and observation can be performed with priority given to fat extraction less affected by blood (step S12).

In the present embodiment, the image signal of G wavelength is used to detect the amount of movement of the image, but the amount of movement may be calculated using a luminance signal calculated from the image signal of RGB. Although motion vectors are calculated at a plurality of points arranged at equal intervals, motion vectors of all pixels on an image may be calculated.

Also, instead of calculating the amount of motion of the image according to equation (5), when calculating the motion vector of each position on the image, the presence or absence of a correlation with the motion vector located around the image is determined. The motion amount of the image may be calculated only from the motion vector determined to be.
In this case, the motion amount can be calculated using the following equation (6).

Here, ci = 0 indicates no correlation with peripheral motion vectors, and ci = 1 indicates correlation with peripheral motion vectors.

If there is no motion vector determined to be correlated, the amount of motion of the image is zero, and the motion vector is processed as a zero vector. The motion vector may be, for example, a disturbance due to a forceps operation or the like during the procedure, as well as the movement of a focused portion on a living tissue. The motion vector due to the disturbance is not correlated with the surrounding motion vector. As shown in Expression (6), the motion amount of the image can be calculated with high accuracy by excluding the motion vector due to the disturbance based on the correlation with the peripheral motion vector. The correlation with the peripheral motion vector may be, for example, correlation if the magnitude of the difference between the vectors is less than a predetermined threshold, and no correlation if the magnitude is greater than the threshold.

Next, a living body observation apparatus according to a third embodiment of the present invention will be described below with reference to the drawings.
In the description of the present embodiment, parts having the same configuration as those of the living body observation apparatus 1 according to the first embodiment described above are assigned the same reference numerals and descriptions thereof will be omitted.

As shown in FIG. 14, the living body observation apparatus 1 according to the present embodiment includes a mist detection unit 35 that detects the generation of mist based on the image signal after the image processing unit 34, and the control unit 16 When the spread of the blood is large and the mist disappears, switching to the second imaging method is performed. When the mist is detected, the first imaging is performed even when the spread of the blood is large. It differs from the living body observation apparatus 1 according to the first embodiment in that the method is maintained.

Smoke and water vapor (hereinafter referred to as mist) are generated by treatment of a lesioned part using an electric scalpel or ultrasonic scalpel during operation. When mist is generated and fills the inside of the body (for example, in the abdominal cavity), the field of vision becomes cloudy and it becomes difficult to visually recognize a lesion. Therefore, in the present embodiment, mist detection is performed to switch the imaging method.

The mist detection unit 35 determines the average luminance YAve (n), the average saturation SAve (n), and the average D range (dynamic range) DAve (dynamic range) of the central region of the image based on the image signal preprocessed in the preprocessing unit 17. n) is calculated and stored in a storage unit (not shown). Here, n indicates the timing at which the image was acquired.

The mist detection unit 35 calculates the mist detection evaluation values Vy (n), Vs (n), and Vd (n) based on Expressions (7), (8), and (9).
Vy (n) = YAve (n) -YAve (nx) (7)
Vs (n) = SAve (n) -SAve (n-x) (8)
Vd (n) = DAve (n)-DAve (n-x) (9)

Here, YAve (n-x) is the average luminance calculated from an image acquired x frames before the current image, and SAve (n-x) is acquired x frames before the current image DAve (n−x) is the average saturation calculated from the image, and the average D range calculated from the image acquired x frames before the current image. An arbitrary number can be set as x.

As can be understood from the equations (7), (8) and (9), Vy (n) is calculated from the average luminance calculated from the image signal at the current time n and the image signal acquired in the past by x Difference with the average brightness. Vs (n) is the difference between the average saturation calculated from the image signal at the current time n and the average saturation calculated from the image signal acquired in the past by x. Vd (n) is the difference between the average D-range calculated from the image signal at the current time n and the average D-range calculated from the image signal acquired in the past by x.

The time change of the evaluation values Vy (n), Vs (n) and Vd (n) will be described with reference to FIG. 16, FIG. 17 and FIG.
When the treatment tool is inserted according to the lesion and treatment is started, mist is generated from the place where treatment is being performed, and it spreads around and fills the body.

While mist is generated, the same condition continues although there is a change in mist concentration. When the generation of the mist stops, the mist in the field of view gradually fades and disappears with the passage of time.
The upper part of FIG. 16, FIG. 17 and FIG. 18 shows the time change of the average luminance value YAve (n), the average saturation SAve (n) and the average D range DAve (n) of the image when the amount of mist changes. FIG.

As shown in FIGS. 16, 17 and 18, the average luminance value YAve (n) increases as mist is generated and fills the body, and the average saturation SAve (n) and the average D range DAve (n) ) Decreases. Then, as the generation of mist stops and disappears, the average luminance value YAve (n) decreases, and the average saturation SAve (n) and the average D range DAve (n) increase. This is because the mist raises the average luminance value YAve (n) to diffusely reflect the illumination and decreases the average saturation SAve (n) and the average D range DAve (n) because the mist is opaque. .

The lower part of FIGS. 16, 17 and 18 shows evaluation values Vy (n) when the average luminance value YAve (n), the average saturation SAve (n) and the average D range DAve (n) change as described above. , Vs (n), Vd (n) over time. Since these evaluation values are difference values, the characteristics are obtained by differentiating the characteristics of the average luminance value YAve (n), the average saturation SAve (n), and the average D range DAve (n) in the upper row, respectively.

When the mist is generated, the evaluation value Vy (n) of luminance has an upward convex characteristic, and the evaluation value Vs (n) of saturation and the evaluation value Vd (n) of D range have a downward convex characteristic. On the other hand, when the mist disappears, the luminance evaluation value Vy (n) has a downward convex characteristic, and the saturation evaluation value Vs (n) and the D range evaluation value Vd (n) have an upward convex characteristic. Have.

In the present embodiment, the mist detection unit 35 determines the presence or absence of the generation of the mist in the following manner with respect to such changes in the evaluation values Vy (n), Vs (n), Vd (n). It is supposed to be. That is, as shown in FIG. 15, the mist detection unit 35 evaluates the luminance value Vy (n) above a predetermined threshold and evaluates the saturation evaluation value Vs (n) and the D range evaluation value Vd ( It is determined that mist has occurred at the time when n) falls below a predetermined threshold (step S13).

Next, in the mist detection unit 35, the time when the evaluation value Vy (n) of the luminance value becomes a local minimum smaller than the first threshold, and the evaluation value of the saturation and the evaluation value of the D range each have the first threshold. Detect the time when the maximum value is larger. Then, after these times, the mist detection unit 35 indicates that the evaluation value of the luminance value exceeds the second threshold, and the evaluation value of the saturation and the evaluation value of the D range each fall below the second predetermined threshold. At time n, it is determined that the mist has disappeared (step S14).

As described above, according to the living body observation apparatus according to the present embodiment, when the mist detection unit 35 detects that the mist is generated, the control unit 16 performs the first operation even when the spread of the blood is large. Thus, the display frame rate can be prevented from being lowered, and the easiness of observation can be improved. On the other hand, when the spread of the blood is large and the mist disappears, the mode is switched to the second imaging method, so fat extraction with little influence of blood is prioritized to detect fat accurately. be able to.

Reference Signs List 1 living body observation apparatus 3, 27 light source unit 11 imaging device (imaging unit)
16 control unit 18 β-carotene detection unit (fat detection unit)
19 Hemoglobin detection unit (blood detection unit)
29 Motion amount detector (Motion detector)
35 mist detection unit S2 illumination step S3 imaging step S4 fat detection step S5 blood detection step S7, S8, S9 control step

Claims (8)

1. A light source unit that emits illumination light to the living tissue;
   An imaging unit configured to capture reflected light of the illumination light emitted by the light source unit in the biological tissue to obtain an image;
   A fat detection unit that detects fat in the image acquired by the imaging unit;
   A blood detection unit that detects blood in the image acquired by the imaging unit;
   A control unit configured to control at least one of the light source unit and the imaging unit based on detection results of the fat detection unit and the blood detection unit;
   The control unit is configured to detect a plurality of band lights having different wavelength bands according to the state of blood detected in the image by the blood detection unit in a state in which fat is detected in the image by the fat detection unit. The living body observation apparatus switches between a simultaneous first imaging method for imaging at the same time and a surface-sequential second imaging method for imaging sequentially.
2. In the first imaging method, the blood detection unit detects hemoglobin based on a ratio between an image signal of a green wavelength band and an image signal of a red wavelength band simultaneously acquired by the imaging unit, The biological observation apparatus according to claim 1, wherein in the second imaging method, the hemoglobin is detected based on a ratio of image signals of two green wavelength bands having a difference in absorbance of hemoglobin sequentially acquired by the imaging unit. .
3. The green wavelength band in the first imaging method is a wavelength band near a wavelength of 510 nm, and the red wavelength band is a wavelength band near a wavelength of 610 nm,
   The biological observation apparatus according to claim 2, wherein a green wavelength band in the second imaging method is a wavelength band near a wavelength of 510 nm and a wavelength near a wavelength of 540 nm.
4. The blood detection unit detects the spread of blood in the image acquired by the imaging unit;
   The biological observation apparatus according to any one of claims 1 to 3, wherein the control unit switches to the second imaging method when the spread of the blood detected by the blood detection unit exceeds a predetermined threshold.
5. A motion detection unit configured to detect an amount of movement of the imaging unit with respect to the living tissue based on the image acquired by the imaging unit;
   The biological observation apparatus according to any one of claims 1 to 4, wherein the control unit switches to the second imaging method when the amount of movement detected by the movement detection unit is smaller than a predetermined threshold.
6. The living body observation apparatus according to claim 5, wherein the motion detection unit identifies a global motion vector of the entire image and a local motion vector, and detects a motion amount based on the global motion vector.
7. A mist detection unit that detects the presence or absence of mist generation based on the image;
   The living body observation apparatus according to any one of claims 1 to 4, wherein the control unit switches to the second imaging method when the mist detection unit detects that the mist disappears.
8. Illuminating the body tissue with illumination light;
   Imaging the reflected light of the illumination light emitted from the illumination step in the living tissue to obtain an image;
   A fat detection step of detecting fat in the image acquired by the imaging step;
   A blood detection step of detecting blood in the image acquired by the imaging step;
   In a state in which fat is detected in the image by the fat detecting step, simultaneously imaging a plurality of band lights having different wavelength bands simultaneously according to the state of blood detected in the image by the blood detecting step A living body observation method comprising a control step of switching between an imaging method of the formula and a field-sequential imaging method of sequentially capturing images.
   

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