JP2000209605A - Video signal processing unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a video signal processing unit by which reproduction of a proper color can automatically be obtained in response to a color tone of an object without manual color tone correction by an operator. SOLUTION: An output signal from a television camera head with a built-in CCD that is mounted to an endoscope observing the inside of a live body is given to an RGB matrix circuit or the like in a CCU, from which color signals are generated. A detection circuit receiving the color signals generates an average signal Rave of one field, they are given to a white balance circuit, from which color signals Rin, Gin, Bin are generated. The signal Rave excellently reflecting a color tone of an object and outputted from the detection circuit is given to a comparator circuit 47 in a matrix coefficient setting circuit 45, where the signal Rave is compared with a discrimination value Vs. A ROM 48 gives a matrix coefficient corresponding to the comparison result to a matrix circuit 38. The matrix circuit 38 automatically applies color correction to the color signals Rin, Gin, Bin for proper color reproduction in response to the color tone of the object according to the matrix coefficient corresponding to the comparison result.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video signal processing apparatus provided with color correction means for a plurality of color signals forming a video signal output to a television monitor.

[0002]

2. Description of the Related Art Conventionally, in a diagnosis / examination using an endoscope, a target subject differs depending on the field. For example, in a surgical operation, the subject is an internal organ, and the subject is relatively magenta. On the other hand, in fields such as otolaryngology, bleeding or the like often occurs relatively during surgery, and the subject often turns red. Conventionally, both of these have been handled by an endoscope apparatus having the same settings. In this case, as a prior example, Japanese Patent Application No. 9-12 / 1990
No. 2604.

[0003]

However, since the color of the subject is different, color reproduction as desired by the operator may not be obtained in some fields. In this case, a color tone correction switch provided on a front panel of the apparatus is adjusted to cope with the situation. However, it was troublesome for the operator to make manual adjustments.

(Object of the Invention) The present invention has been made in view of the above points, and an appropriate color reproduction is automatically obtained according to the color tone of a subject without an operator manually correcting the color tone. It is an object of the present invention to provide a video signal processing device capable of performing the above.

[0005]

A video signal processing device having a color correcting means for correcting a color state of an image displayed on a display means by inputting a plurality of color signals and adjusting the signal levels of the color signals. In the apparatus, detecting means for calculating an average value of at least one signal of the plurality of color signals, and automatically detecting at least one color signal of the plurality of color signals based on an output of the detecting means. By providing the color correction means for correcting, it is possible for the operator to perform color correction for automatically producing appropriate color reproduction without manually performing color correction according to the color tone of the subject.

[0006]

Embodiments of the present invention will be described below with reference to the drawings. (First Embodiment) FIGS. 1 to 5 relate to a first embodiment of the present invention, FIG. 1 shows a configuration of an endoscope apparatus provided with the first embodiment, and FIG. Shows the configuration of the detection circuit,
3 shows the configuration of the white balance coefficient setting circuit, FIG. 4 shows the configuration of the matrix coefficient setting circuit, and FIG. 5 shows the operation of the matrix coefficient setting circuit.

As shown in FIG. 1, an endoscope apparatus 1 provided with a first embodiment is an optical endoscope 2 and a television camera head 3 mounted on the endoscope 2 and incorporating image pickup means. When,
A light source device 4 that supplies illumination light to the endoscope 2 and a camera control unit (hereinafter, CCU) as a video signal processing device according to the first embodiment of the present invention that performs signal processing on an imaging unit of the television camera head 3 5)
And a television monitor 6 for displaying a standard video signal generated by the CCU 5 in color.

The endoscope 2 has an elongated insertion section 7, a grip section (or operation section) 8 provided at the rear end of the insertion section 7, and an eyepiece section provided at the rear end of the grip section 8. 9 is provided. A light guide 11 for transmitting illumination light is inserted into the insertion portion 7, and the light guide 11 is connected to a light guide base 12 provided on the grip portion 8.
3 is connected to a light source device 4.

A lamp 15 which is turned on by a power supply supplied from a power supply circuit 14 is housed in the light source device 4, and white light of the lamp 15 is condensed by a lens 16 and is incident on an incident end face of a light guide cable 13. The light is transmitted through the light guide base 12 to the light guide 11 in the endoscope 2 and is emitted from the light guide tip surface attached to the illumination window at the tip of the insertion section 7 to illuminate a subject such as an affected part.

At the tip, an objective lens 18 attached to an observation window provided adjacent to the illumination window is provided. By this objective lens 18, an image of a subject is transmitted by, for example, a relay lens system 19 as image transmission means. Thereafter, the light is transmitted to the end face side, and can be magnified and observed by an eyepiece 20 provided in the eyepiece 9.

An image forming lens 22 is arranged on the television camera head 3 provided with a mount portion mounted on the eyepiece 9 so as to face the eyepiece 20. At the image forming position, for example, a CCD 23 as an image sensor is provided. Are located.

A color separation filter 24 such as a mosaic filter is disposed on the imaging surface of the CCD 23, and an image color-separated by the color separation filter 24 is formed on the imaging surface of the CCD 23.

The CCD 23 is connected to a signal line. The signal line is inserted through a camera cable 25 extending from the television camera head 3, and a connector 26 at the rear end is connected to a C line.
It is detachably connected to CU5.

The CCD driver 31 in the CCU 5
After the CCD drive signal is applied, the signal charges photoelectrically converted and accumulated by the CCD 23 are read out and input to the preamplifier 32, where the signal charges are amplified so as to compensate for the loss due to cable transmission. 33.

For example, CDS (correlated double sampling)
Or after pre-processing such as S / H (sample and hold) processing, the analog signal is converted from an analog signal to a digital signal by the A / D converter 34, and then separated into luminance and color signals. The luminance signal Y and the chrominance signal C
For example, two color difference signals Cr and Cb.

These digital luminance signal Y and color difference signal C
r and Cb are R to convert these signals into RGB signals.
A digital RGB signal that is input to the GB matrix circuit 36
After being converted into a signal, it is input to the white balance circuit 37.

That is, the digital luminance signal Y and the color difference signals Cr and Cb are converted by the conversion matrix A as follows.
RGB signals as digital red, green and blue color signals (3
(Primary color signal).

[0018]

(Equation 1) The digital RGB signals are subjected to white balance adjustment by a white balance circuit 37, and then the matrix circuit 3
8, and after being color-corrected, input to a D / A converter 39, which converts the digital signal into an analog signal,
Further, after being converted into a standard video signal in the post-processing circuit 40, it is output to the television monitor 6.

The digital RGB signals output from the RGB matrix circuit 36 are input to a detection circuit 41, which performs detection for calculating an average value of an image. FIG. 2 shows the configuration of the detection circuit 41. That is,
The R, G, and G color signals are input to one-field average value calculation circuits 42R, 42G, and 42B, respectively, and the signals for one field are cumulatively added and then divided by the total number of pixels. Signals Rave, Gave, and Bave of the average value are output. In addition, the average value for one frame may be calculated instead of the average value for one field.

The signals Rave, Gave, Bav of these average values
The signal e is input to a white balance coefficient setting circuit (abbreviated as W / B coefficient setting in FIG. 1) 43, as shown in FIG. Rave is input to the matrix coefficient setting circuit 45.

FIG. 3 shows a white balance coefficient setting circuit 43.
Is shown. Signals Rave and Gave and signals Gave and Bave
Are input to the division circuits 44a and 44b, respectively, and Gave is divided by Rave and Bave signals, respectively.
/ Rave and Gave / Bave are generated, and the Gave / Rave
The signal values of ave and Gave / Bave are output to the white balance circuit 37 as white balance adjustment coefficients.

The white balance circuit 37 multiplies the RGB signals output from the RGB matrix circuit 36, for example, the R and B signals by multiplication circuits 46a and 46a.
b, Gav output from the division circuits 44a and 44b
The adjusted Rin, Gin, and Bin signals obtained by performing white balance adjustment on the signal obtained by multiplying e / Rave and the value of Gave / Bave are generated as input signals to the matrix circuit 39.

The matrix coefficient setting circuit 45 to which the output signal of the detection circuit 41 is input has a comparison circuit between the average value signal Rave and the discrimination value (reference value) Vs as shown in FIG. For example, a read-only memory (abbreviated as ROM) as matrix coefficient storage means according to the comparison result
The matrix circuit 3 reads the matrix coefficient read from
8 is output.

In this embodiment, the ROM 47 stores matrix coefficient values for performing different color corrections when the average value signal Rave is larger than the discrimination value Vs and smaller than the discrimination value Vs.

The matrix circuit 38 automatically converts the color-corrected Rmtx, Gmtx, and Bmtx signals, which have been color-corrected, by using different matrix coefficients depending on whether the average value signal Rave is larger or smaller than the discrimination value Vs. Generate and D
The signal is output to the post-processing circuit 40 via the / A converter 39.

That is, in the present embodiment, a plurality of color signals are generated from the signals picked up by the CCD 23, and the average value of one color signal that best represents the color tone of the subject in the color signals is set in advance. And a matrix coefficient provided corresponding to the comparison result is read from the comparison result, and color correction is performed by the color correction unit using the matrix coefficient. The color is corrected so as to perform the optimum color reproduction for the color tone.

More specifically, when the signal does not satisfy Rave> Vs (that is, when Rave ≦ Vs), the matrix circuit 39 performs the following operation.

[0028]

(Equation 2) In other words, in the case of a subject having a small amount of red component, the matrix coefficient setting circuit 45 outputs a matrix coefficient M having the same color tone.

Conversely, when Rave> Vs, the subject has a large amount of red component, and the matrix circuit 39 performs color correction so as to suppress the red component of the RGB signal. In this case, the following calculation is performed.

[0030]

(Equation 3) That is, in the case of a subject having many red components, the matrix coefficient setting circuit 45 outputs a matrix coefficient M for performing color correction for suppressing the red component.

Next, the operation of the present embodiment will be described. A case will be described in which the endoscope apparatus 1 observes, for example, an organ or an ear nose inside a patient's abdomen as a subject.

The insertion section 7 of the endoscope 2 is inserted into the abdomen or the nose and nose to observe the organ or the nose and nose. Then, a signal imaged by the CCD 23 under illumination by the light source device 4 is amplified by a preamplifier 32, pre-processed by a pre-processing circuit 33, and then converted into a digital signal by an A / D converter 34 to be Y / C. The signal is input to a separation circuit 35 and separated into a luminance signal Y and color difference signals Cr and Cb as color signals C.

The luminance signal Y and the color difference signals Cr and Cb are RG
The signal is input to the B matrix circuit 36 and converted into an RGB signal.

The R, G, and B signals of the R, G, and B color signals are calculated by the detection circuit 41, and the signals Rave, Gave, and Bave of the average value of one field are input to the white balance coefficient setting circuit 43. The signal Gave is used as a reference signal, and the magnitudes of the other two signals are the value Gave obtained by dividing the signal Gave by the signals Rave and Bave.
/ Rave, Gave / Bave, and these values are input to the white balance circuit 37 to be R, G, B, respectively.
The signals Rin, Gin, and Bin are multiplied by the color signals of the above and white balance adjusted, and input to the matrix circuit 38 for performing color correction.

The average value signal Rave of one field output from the detection circuit 41 is output from the matrix coefficient setting circuit 4.
5, the color-corrected signals Rmtx, Gm that have been automatically color-corrected by different matrix coefficients depending on whether the average signal Rave is larger or smaller than the discrimination value Vs.
Generate tx and Bmtx.

The image is output to the post-processing circuit 40 via the D / A converter 39, converted into a standard video signal, and the television monitor 6 displays the subject image picked up by the CCD 23 in color.

FIG. 5 shows a color correction process by the matrix coefficient setting circuit 45. As shown in step S1, the input signal Rave is output to the comparison circuit 47 by a comparison value V.
s to determine whether it is greater than this value.
If ave> Vs is not satisfied, the matrix coefficient M that does not substantially perform color correction is R, as shown in step S2.
It is read from the OM 48 and output to the matrix circuit 38. Then, color correction is performed by matrix processing as in equation (2) (in this case, color correction is not substantially performed).

That is, it is determined that the subject does not have much red component, and the signals Rin, Gin,
Bin is not subjected to color correction by the matrix circuit 38, and is output as it is as corrected color signals Rmtx, Gmtx, Bmtx of the signals Rin, Gin, and Bin.

On the other hand, by the judgment processing of step S1, R
If ave> Vs, as shown in step S3, the Trix coefficient M for performing color correction for suppressing the red component is RO
It is read from M48 and output to the matrix circuit 38. Then, color correction is performed by matrix processing as in equation (3).

Therefore, when the subject has a large amount of red component, the red component is suppressed, the color reproduction at the time of bleeding when used in otolaryngology can be improved, and when observing organs in the body cavity without bleeding. Is output without color correction, so that appropriate color reproduction can be achieved in such a case.

Therefore, according to the present embodiment, it is determined whether or not the red component of the subject is greater than the value for determination, and color correction suitable for the color tone of the subject is automatically performed according to the determination result. There is a color correction means to perform the color correction (including the case where the color correction is not required, including the case where the color correction is not necessary), so that the operator does not need to perform the troublesome work of manually performing the color correction according to the use environment. it can.

(Second Embodiment) Next, a second embodiment of the present invention will be described. The configuration of the present embodiment is the same as that of the first embodiment except for the configuration of the matrix coefficient setting circuit 45, and a description thereof will be omitted.

In the matrix coefficient setting circuit of the present embodiment, in the matrix coefficient setting circuit 45 of FIG. 4, a division circuit is provided before the comparison circuit 47, and the signal Rave is changed to the signal Gave
Is obtained by dividing the level ratio k by the formula (1), and the level ratio k is inputted to the comparison circuit 47.

Accordingly, only the operation of the matrix coefficient setting circuit is different from that of the first embodiment. The operation of the matrix coefficient setting circuit will be described with reference to FIG.

The signal Rave and the signal Gav output from the detection circuit 41 are input to a matrix coefficient setting circuit, and a level ratio k = Rave / Gave is obtained as shown in step S11. Then, as shown in the level ratio k step S12, the comparison circuit 47 compares the value with the determination value Vs.

If the result of the comparison does not correspond to k <Vs, a matrix coefficient M for performing the operation of the above equation (2) as shown in step S13 is read out.
If> Vs, the matrix coefficient is set so as to perform the operation of equation (3).

According to the present embodiment, signals Rave and Gave
Since the switching setting of the matrix coefficient is performed using the information of the two colors, the color tone of the subject can be determined more appropriately than in the first embodiment.

For example, when the affected part having a large red component is observed (imaged) at different distances, the level of the signal Rave corresponding to the red component is different, and the color correction varies depending on the distance in the first embodiment. However, in the second embodiment, such a variation can be reduced. Therefore, more appropriate color correction can be performed by setting the switching of the matrix coefficient based on the determination result.

Also in this embodiment, the color correction is automatically performed so that appropriate color reproduction is performed even if the observation (imaging) state of the subject changes, so that the operator manually performs color correction which has been conventionally performed. No adjustment is required, and the trouble of the operator can be eliminated.

In the above-described embodiment, the case where two color corrections are performed according to the magnitude of a signal for simplification has been described. For example, in the second embodiment, a plurality of level ratios k are set. Discrimination values Vs1, Vs2 (for example, Vs1
> Vs2), and the comparison result (for example, k> Vs
1, Vs1 ≧ k> Vs2, Vs2 ≧ k), and the color correction may be changed in three cases. Also,
The color correction may be changed in more cases by using three or more determination values.

In each of the above-described embodiments, the description has been made of the case where the endoscope 2 is a television camera external endoscope in which the television camera head 3 having the image pickup means is mounted. It is obvious that the present invention can be applied to the case of an electronic endoscope having a built-in image sensor.

[Supplementary Notes] In a video signal processing device having a color correction unit for correcting a color state of an image displayed on a display unit by adjusting a signal level of the plurality of color signals and adjusting a signal level of the plurality of color signals, Detecting means for calculating an average value of at least one of the signals; and color correcting means for automatically correcting at least one of the plurality of color signals based on an output of the detecting means. A video signal processing device.

2. In a video signal processing apparatus having a plurality of color signals input and adjusting a signal level of the color signals to correct a color state of an image displayed on the display means, Detecting means for calculating an average value of at least one of the signals, comparing means for comparing the output of the detecting means with a reference value, and automatically switching the operation coefficient of the color correcting means based on the output of the comparing means A video signal processing device characterized by the above-mentioned.

3. In a video signal processing device having a color correction unit for correcting a color state of an image displayed on a display unit by adjusting a signal level of the plurality of color signals and adjusting a signal level of the plurality of color signals, Detecting means for calculating an average value of at least two of the signals; calculating means for calculating a level ratio of a plurality of outputs of the detecting means; comparing means for comparing the level ratio with a reference value; A video signal processing device for automatically switching the operation coefficient of the color correction means based on

4. The video signal processing device according to any one of supplementary notes 1 to 3, wherein the video signal processing device inputs a video signal from an imaging device attached to an eyepiece of an endoscope. 5. The video signal processing device according to any one of appendices 1 to 3, wherein the video signal processing device inputs a signal from an imaging element provided at a distal end of an insertion portion of the endoscope. 6. The video signal processing device according to any one of supplementary notes 1 to 5, wherein the plurality of color signals are red, blue, and green color signals.

[0056]

As described above, according to the present invention, a plurality of color signals are inputted, and the color level of the image displayed on the display means is corrected by adjusting the signal levels of the color signals. In a video signal processing device having a correction unit,
Detecting means for calculating an average value of at least one of the plurality of color signals; and a color for automatically correcting at least one of the plurality of color signals based on an output of the detecting means. Since the correction means is provided, it is possible to perform color correction for automatically producing appropriate color reproduction without manually performing color correction by an operator according to the color tone of the subject.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of an endoscope apparatus including a first embodiment of the present invention.

FIG. 2 is a block diagram illustrating a configuration of a detection circuit.

FIG. 3 is a block diagram showing a configuration of a white balance coefficient setting circuit and a white balance circuit.

FIG. 4 is a block diagram illustrating a configuration of a matrix coefficient setting circuit.

FIG. 5 is a flowchart showing the operation of color correction by a matrix coefficient setting circuit.

FIG. 6 is a flowchart illustrating the operation of color correction according to the second embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Endoscope apparatus 2 ... Endoscope 3 ... TV camera head 4 ... Light source device 5 ... CCU 6 ... TV monitor 7 ... Insertion part 11 ... Light guide 15 ... Lamp 18 ... Objective lens 19 ... Relay lens system 23 ... CCD DESCRIPTION OF SYMBOLS 31 ... CCD driver 33 ... Pre-process circuit 36 ... RGB matrix circuit 37 ... White balance circuit 38 ... Matrix circuit 40 ... Post-process circuit 41 ... Detection circuit 43 ... White balance coefficient setting circuit 45 ... Matrix coefficient setting circuit 47 ... Comparison circuit 48 … ROM

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4C061 AA11 AA12 BB02 CC06 DD00 LL03 MM05 NN05 SS11 SS23 TT03 TT13 5C066 AA01 BA20 CA17 DD07 DD08 EA14 EB01 EE02 EE04 GA01 GA02 GA05 HA02 KA12 KD02 KE04 KE04 KE04 KE04 KM06 KM10

Claims (1)

[Claims] 1. A video signal processing apparatus comprising: a plurality of color signals input thereto; and a color correction unit for correcting a color state of an image displayed on a display unit by adjusting a signal level of the color signals. Detecting means for calculating an average value of at least one of the plurality of color signals; and color correction for automatically correcting at least one of the plurality of color signals based on an output of the detecting means. A video signal processing device comprising: means.