DE4109773C2 - Endoscope light source arrangement for generating visible and infrared illuminating light - Google Patents

Description

The invention is based on a light source arrangement for an endoscope according to the preamble of claim 1, such as it is known from DE 37 40 318 C2.

It is known that information about the distribution hemoglobin concentration or oxygen saturation in the bloodstream under a mucous membrane from a near infrared Image with a wavelength in the range of for example, 805 nm can be obtained using a sequential endoscope system Color change of the type described above.

It was first a special endoscope system exclusively for processing such infrared images created.  

With such a special system, however, the image viewing Wavelength band set and a normal one Color image viewing is not possible. The system therefore there is a lack of general usage properties, so that it is inconvenient and impractical.

DE 37 40 318 C2 describes a light source arrangement of the type mentioned, in which the used Color filters in addition to the specific one assigned to them Wavelength range in the visible range also infrared radiation let through. Of the two notch filters lets an infrared radiation through and blocks in visible area while the other visible light lets through and blocks in the infrared range. By optional Switch on one of the two notch filters in the Light path in addition to the color filters is either one Recording in the visible area or recording in the infrared range. A mixed form, that is a simultaneous image of an object to be viewed with visible light and infrared radiation not possible.

The invention has for its object to develop the light source arrangement known from DE 37 40 318 C2 so that with it lighting for normal color image viewing and lighting for image processing is feasible, both on visible light as well as infrared light rays of a specific wavelength range based, with a simple structure excellent image quality can be achieved should.  

This task is the subject of the claim 1 solved.

Advantageous refinements of the invention result itself from the subclaims.

Embodiments of the Invention are shown in the drawing and in fol described in more detail. It shows

Fig. 1 schematically shows a block diagram of a first embodiment of the invention;

Figure 2 shows a color filter array for the first embodiment.

Fig. 3 is a rejection filter arrangement for the first embodiment;

Fig. 4 is a graph of the spectral characteristics of a color filter Transmis sion for the first embodiment;

Fig. 5 is a graph of the spectral Transmis sion properties of another color filter for the first exporting approximately, for example;

Fig. 6 is a diagram showing the spectral transmission characteristics of exemplary implementation of a direct white color filter for the first off;

Fig. 7 is a graph of the spectral characteristics Transmis sion of a first notch filter for the first exporting approximately, for example;

Fig. 8 is a graph of the spectral characteristics Transmis sion of a second notch filter for the first guidance from, for example;

Fig. 9 schematically shows a block diagram of a second embodiment of the present invention;

FIG. 10 is a blocking filter arrangement for the second embodiment;

Fig. 11 shows another Sperrfilteranord voltage for the second game Ausführungsbei.

Fig. 1 shows an endoscope system according to a first embodiment of the invention; a solid-state image sensor 3 is arranged within the distal end portion of the insertion part 1 of an endoscope in a position in which the image of an object is formed by an objective lens 2 . For example, a CCD element (charge-coupled switching element) can be used as the solid-state image sensor 3 .

An illuminating optical fiber bundle 5 transmits light for illuminating the observation area. The incident end face 5 a of the fiber bundle 5 is exposed to a light source 10 for the endoscope.

The light source assembly 10 comprises a serving as Lichtquel le lamp 11 and a converging lens 12 , which bundles the light emanating from the lamp 11 onto the incident end face 5 a of the optical fiber bundle 5 . A video processor 13 processes an image signal which is emitted by the solid-state image sensor 3 in the insertion part 1 of the endoscope and outputs a video signal to a monitor 16 .

A first filter holder 21 and a second filter holder 22 are provided in the illuminating light path between the lamp 11 and the converging lens 12 .

The first filter holder 21 has a first color filter 23 R, a second color filter 23 G and a third color filter 23 B, which are arranged thereon concentrically and at an angular distance of 120 °, so that each of the color filters can be pivoted into the illuminating light path, such as Fig. 2 shows.

The second filter holder 22 has a first blocking filter 24 I and a second blocking filter 24 J, which are arranged thereon in such a way that each of the blocking filters can be pivoted into the illuminating light path, as shown in FIG. 3.

FIGS. 4, 5 and 6 show the spectral Transmis sion properties of the first color filter 23 R, 23 G of the second color filter and the third color filter 23 B.

The first color filter 23 R transmits red light in a wavelength range which extends from approximately 600 nm to 700 nm; however, it transmits no visible light in the other wavelength ranges and no infrared rays with shorter wavelengths than about 900 nm, as can be seen in FIG. 4.

The second color filter 23 G transmits green light in the wavelength range from about 500 nm to 600 nm, but transmits no visible light in the other wavelength ranges and no infrared rays with shorter wavelengths than about 900 nm, as shown in FIG. 5.

The third color filter 23 B transmits blue light in the wavelength range from approximately 400 nm to 500 nm, but does not transmit visible light in the other wavelength ranges, as shown in FIG. 6. However, the third color filter 23 B transmits infrared rays with wavelengths longer than approximately 800 nm. As a result, infrared rays with wavelengths in the range between approximately 800 nm and 900 nm only pass through the third color filter 23 B.

FIGS. 7 and 8 show the spectral TRANSMISSI onseigenschaften of the first blocking filter 24 I and the second notch filter 24 J.

The first blocking filter 24 I blocks all infrared rays, but transmits visible light in the same way as conventional infrared blocking filters, as shown in FIG. 7.

The second blocking filter 24 J blocks blue light in the wavelength range between approximately 400 nm and 500 nm and infrared rays in the wavelength range above 850 nm; however, it transmits visible light and infrared rays between these two ranges, as can be seen in FIG. 8.

The first filter holder 21 shown in FIG. 1 is driven in rotation by a first motor 26 in such a way that it rotates at a constant speed in synchronism with the signal processing in the video processor 13 . The first motor 26 is operated by a driver circuit 27 in response to a control signal which is output by the video processor 13 .

The second filter holder 22 can be stopped in one of two positions and is rotated further by 180 ° by a second motor 28 , so that the first blocking filter 24 I or the second blocking filter 24 J can optionally be pivoted into the light path.

A changeover circuit 30 switches from one stop position of the second motor 28 to the other stop position as a function of a control signal from the video processor 13 , so that either the first blocking filter 24 I or the second blocking filter 24 J can optionally be pivoted into the illuminating light path. The arrangement can be such that the second filter holder 22 is pivoted by a manual actuation and that a switch is made between the first and second blocking filters 24 I and J, respectively.

If, in the first embodiment described above, the first blocking filter 24 I is pivoted into the illuminating light path, all infrared rays are blocked and an image with sequential color change is generated by means of the illuminating light, which contains three primary colors, namely red, green and blue by the first, second and third color filters 23 R, 23 G and 23 B are successively pivoted into the illuminating light path. As a result, a normal color image with normal brightness and a normal number of images is obtained; this image is displayed on the monitor 16 .

If the second blocking filter 24 J is pivoted into the illumination light path, visible blue light is blocked, while instead infrared rays are transmitted in the range from approximately 800 nm to 850 nm for illumination. There is no change in the lighting with red and green light.

Accordingly, if the image signal of an image which is generated by illumination by the third color filter 23 B al line is output for itself, a video signal can be obtained which is based on the illumination with infrared rays in the range from approximately 800 nm to 850 nm. The image signals of the images which are generated by the first color filter 23 R and the second color filter 23 G are used to obtain images which are based on illumination with red light or green light. As a result, information about various facts of the blood flow under a mucous membrane can be obtained via these video signals (R, G, and infrared images).

It should be noted that the use of infrared rays in the range of 805 nm as infrared lighting for Ge Obtaining information about the blood flow on the gun most estimated; if the present inven should be used for other purposes Infrared wavelengths are selected, which spe for this task are most suitable.

Fig. 9 shows a second embodiment of the invention, in which an image signal, which is output by the solid-state image sensor 3 in the insertion part 1 of the endoscope, is separated into two signals in a signal separation circuit 15 . The two signals are then transmitted to a first video processor 13 or a second video processor 14 , which give video signals to a first monitor 16 or a second monitor 17 .

The second filter holder 22 has a first blocking filter 24 I and a second blocking filter 24 J, which are arranged concentrically thereon, each filter extending over 180 °, so that each blocking filter can be pivoted into the illumination light path, as shown in FIG. 10. The first blocking filter 24 I and the second blocking filter 24 J have the same properties as the blocking filter described with reference to the first exemplary embodiment.

The first filter holder 21 and the second filter holder 22 are driven by a first motor 26 and a two-th motor 28 so that they each circulate at constant speed and synchronously with the signal processing device in the first video processor 13 or second video processor 14 . The first filter holder 21 has a speed that is, for example, twice the speed of the second filter holder 22 .

Driver circuits 27 and 29 for the first motor 26 and the second motor 28 receive control signals from a synchronizing circuit 18 which synchronizes the operation of the driver circuits 27 and 29 with the timing of the signal separation, which is carried out in the signal separation circuit 15 .

As a result, an image which is obtained when the first blocking filter 24 I is pivoted into the illumination light path is displayed on the first monitor 16 , while an image which is obtained when the second blocking filter 24 J is pivoted into the illumination light path, on the second monitor 17 is shown.

The arrangement of the rest of the present The embodiment is that of the first embodiment same example, so that a detailed description is no longer required.

If, in the second embodiment described above, the first blocking filter 24 I is pivoted into the illuminating light path, all infrared rays are blocked; by controlling the most video processor 13 , an image with sequential color change is generated by means of the illuminating light, which contains three primary colors, namely red, green and blue, the first, second and third color filters 23 R, 23 G and 23 B successively in the illumination light path can be swiveled in. As a result, a normal color image is obtained, which is displayed on the monitor 16 .

On the other hand, if the second blocking filter 24 J is pivoted into the illuminating light path, visible blue light is blocked, while infrared rays in the range from approximately 800 nm to approximately 850 nm are instead transmitted for the illumination. There are no changes to the lighting with red and green light.

Accordingly, a video signal is obtained from an image which is generated by the light passing through the third color filter 23 B and is based on the illumination by infrared rays in the range from approximately 800 nm to 850 nm. From the images generated by the light passing through the first color filter 23 R or the second color filter 23 G, video signals are obtained which are based on the illumination with red or green light.

Accordingly, by controlling the second video processor 14 through these video signals (R, G, and infrared images), an infrared false color image is displayed on the second monitor 17 and information about various facts of the blood flow under a mucous membrane can be obtained by means of image processing .

The speed of the first filter holder 21 only has to be an integer multiple of the speed of the second fil terhalters 22 . In the event that, for example, the image processing speed is slow, the area of the second blocking filter 24 J can be reduced in order to reduce the sampling ratio, as shown in FIG. 11.

It is also possible to arrange two or more of the color filters 23 R, 23 G, 23 B so that infrared rays are transmitted in a specific wavelength range (for example from 800 nm to 900 nm).

It should be noted that the use of infrared rays in the range of 805 nm for infrared lighting Obtaining information about the blood flow as at be viewed cheapest; if the present Er should be used for other purposes th infrared wavelengths are selected for this are suitable for special tasks, such as when you leave leadership example.

According to the present invention, it is not possible just do a normal color image viewing, but also to gain infrared information, and with an extremely simple structure, in which a second notch filter in addition to a first  Blocking filter is provided, as it is conventional is arranged in the illuminating light path, such that the two infrared cut filters are optional can be pivoted into the illuminating light path, whereby the properties of the color filter only to be changed.

Accordingly, the arrangement according to FIG the invention from the point of view of costs and Function in a simple way in a normal endoscope with sequential color change and can be installed can be used by anyone anywhere, as ever occasion demands it.

In addition, an ordinary color image and an In infrared information image simultaneously in real time extremely simple arrangement, which in a simple way by changing the property the color filter is reached. As a result, can the medical examination options a real time comparison between the normal color image and significantly improved the infrared information image become. Even if the shape of the inner surface is one hollow organ of the patient through an infrared informa endoscope can not be seen, the endoscope si cher be carried out, since at the same time monitoring possible at any time using a normal color image is.

Claims (6)

1. Light source arrangement for an endoscope, comprising a color change imaging device, a plurality of color filters ( 23 R, 23 G, 23 B) which transmit or transmit light rays in different visible areas, the color filters ( 23 R, 23 G, 23 B) sequentially into an illuminating light path for supplying illuminating light to an illuminating light guide ( 5 ) of the endoscope ( 1 ) and wherein at least one of the color filters ( 23 R, 23 G, 23 B) is designed so that it emits infrared rays of a specific wavelength range in addition to light transmits in a certain visible range, a first blocking filter ( 24 I), which blocks infrared rays, a second blocking filter ( 24 J), which transmits infrared rays in the specific wavelength range, but blocks visible light that passes through the at least one color filter ( 23 B) is transmitted which transmits infrared rays of this specific wavelength range, and means ( 22 ) for selectively introducing each of the first ( 24 I) or second ( 24 J) blocking filter into the illuminating light path, characterized in that the second blocking filter ( 24 J) blocks all infrared rays transmitted through the other color filters ( 23 R, 23 G) are transmitted that the other color filters ( 23 R, 23 G) do not transmit infrared rays with shorter wavelengths than at least 900 nm, while the at least one color filter ( 23 B) transmits infrared rays with longer wavelengths than at least 800 nm, and that second blocking filter ( 24 J) blocks infrared rays with wavelengths greater than at least 850 nm and the light transmitted by the at least one color filter ( 23 B) in the visible range. 2. Light source arrangement according to claim 1, characterized in that the means for introducing the blocking filter ( 24 I, 24 J), the first ( 24 I) and the second ( 24 J) blocking filter alternatively and in synchronism with the color filters ( 23 R, 23 G , 23 B) into the illuminating light path. 3. Light source arrangement according to claim 1 or 2, characterized in that the color filter a first color filter ( 23 R) for transmitting red light, a second color filter ( 23 G) for transmitting green light and a third color filter ( 23 B) for transmission of blue light, the latter transmitting infrared rays in the specific wavelength range. 4. Light source arrangement according to one of claims 1 to 3, characterized in that the specific infrared wavelength range includes the wavelength of 805 nm. 5. Light source arrangement according to one of claims 2 to 4, characterized in that the cycle with which the color filters ( 23 R, 23 G, 23 B) are introduced sequentially into the illuminating light path is an integer multiple of the cycle with which the first and second blocking filter ( 24 I, 24 J) are introduced. 6. Light source arrangement according to one of claims 2 to 5, characterized by a first monitor ( 16 ) for displaying an image, which is obtained by lighting with the color filter ( 23 R, 23 G, 23 B) passing light, during the first Blocking filter ( 24 I) is introduced into the illuminating light path, and a second monitor ( 17 ) for displaying an image which is obtained by illuminating light passing through the color filters ( 23 R, 23 G, 23 B), while at the same time the second blocking filter ( 24 J) is introduced into the illuminating light path.