JPS62182705A - Endoscope device - Google Patents

Abstract

PURPOSE:To quickly and easily distinguish an affected part and a normal part from each other by extracting an image signal in a wavelength area where the affected part in a living body is identified from the normal part. CONSTITUTION:A rotary filter 22 is equally divided into three parts 40-42, and the part 40 permits the light having 700-800nm wavelength (red) to pass through, and the part 41 permits the light having 800-900nm wavelength (infrared area) to pass through, and the part 42 permits the light having 600-700nm wavelength (orange) to pass through. A signal switching circuit 28 is driven synchronously with rotation of this filter 22, and the image signal obtained by the light transmitted through the red part 40 is supplied to a green channel through a green output terminal 28G and is projected as a green image on a monitor cathode-ray tube 34, and the image signal obtained by the light transmitted through the infrared area part 41 is allowed to pass a red output terminal 28R and is displayed as a red image, and the image signal obtained by the light transmitted through the orange part 42 is allowed to pass a blue output terminal 28B and is displayed as a blue image.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an endoscope device used for observing the inside of a living body cavity or a cavity such as a mechanical component.

Conventionally, in such endoscopes, an image of the object to be observed is led out of the living body cavity or cavity through an optical fiber east, and an optical image formed on the output end face of the optical fiber is transmitted through an eyepiece system. I am observing. Another method is to install a solid-state imaging device at the tip of the endoscope sheath instead of the optical fiber described above, and convert the optical image formed on the light-receiving surface of the solid-state imaging device into an electrical signal. It has also been proposed to lead the signal out of the body cavity or cavity using a wire and display it on a TV monitor after performing necessary signal processing.

In the endoscope described above, the information obtained from the object to be observed is fixed to the visible light wavelength region.

In other words, in the former case, the image is viewed optically directly with the naked eye, so it is naturally impossible to observe b outside the visible wavelength range, and in the latter case, the solid-state imaging device is also sensitive to the infrared wavelength j)n range, so it cannot be observed in the infrared wavelength range. Image information in the region can be detected, but when colorizing the image, image information in the infrared wavelength region becomes a hindrance to achieving color balance. Therefore, in order to improve color fidelity, it is common practice to use an infrared cut filter or the like to prevent illumination light in the infrared wavelength range from irradiating the object to be observed, or even if it is irradiated, the light receiving surface of the solid-state image sensor is It is necessary to provide a filter to prevent this from occurring.

When observing an image of an object to be observed using such an endoscope, it is necessary to detect subtle differences in color tone to distinguish between an affected area and a normal area, especially in a living body. Generally, detecting (recognizing) the difference requires a high degree of knowledge and experience, and it takes a long time to detect it, and requires concentrated attention during the detection.

The present invention aims to eliminate the above-mentioned drawbacks and to enable quick and easy identification of affected areas and normal areas. As a method to increase the discriminative ability of endoscopic equipment for observation of affected and normal parts in vivo,
The present invention employs a method of converting invisible information obtained by infrared irradiation into visible information. As is generally known, solid-state imaging devices have high sensitivity in the near-infrared region. It is also known that illumination light sources generally emit more energy in the infrared wavelength region than in the visible wavelength region. By the way, it can be predicted that the amount of light reflected from an object to be observed is large in the red (long wavelength) side of the visible light wavelength region in a living body because blood is red in color. It has also been announced that the reflectance increases with near-infrared light. For these reasons, there is a good possibility that information obtained from infrared light in a living body is useful for extracting features in a living body. Image information obtained using infrared light in this way is displayed on a TV monitor in colors of specific wavelengths. Only images in different infrared wavelength regions are
It is also possible to display (red), (green), and (blue) on the V monitor, or to display images obtained in the visible wavelength region (for example, a red image) and those obtained in the infrared wavelength region. They may be displayed simultaneously. In short, it is important to be able to extract image signals in a wavelength range that characterizes an affected area within a living body as a normal area.

The endoscope apparatus of the present invention includes means for illuminating an object to be observed in time series with at least one light in an infrared wavelength range and at least one light in a wavelength range different from the infrared wavelength range; An optical system that is installed at the tip of the part that is inserted into the object to be observed and that receives light from the object to form an image of the object on an imaging plane; a solid-state imaging device that converts an optical image of an object to be observed into an electrical signal; and a plurality of frame memories that store electrical signals representing images of the object to be observed by light in each of the wavelength ranges output from the solid-state imaging device. , and means for displaying an image in response to electrical signals selectively read out from the plurality of frame memories.

Next, the present invention will be explained in detail according to the drawings.

FIG. 1 Δ and B show the reflection spectra of the human body Va. Figure 1A shows the spectrum of the stomach, which is approximately 400 nm-
It is flat up to a wavelength of 1200 nm, and its reflectance is several 1
It is 0%. On the other hand, Figure 1B shows the spectrum of blood, which is 40
It varies from several % to nearly 100% from 0 nm to 1200 nm. Comparing the two, we find that especially in the infrared wavelength region (8
It can be seen that the difference is large between 00 nm and 1200 nm).

For example, if there is tissue resembling blood or something that contains a large amount of blood in the stomach, and you are trying to recognize its existence, the difference will be clearer if you compare it in the near-infrared wavelength region. However, it is clear that the effect is significant.

Current optical endoscopes have a human specific luminous efficiency (40,0n).
It is possible to make a judgment by observing only in the wavelength range (m to 700 nm). On the other hand, the sensitivity range of CCD is 400n
m to 1200 nm, which is sufficient to obtain information in the near-infrared wavelength region. Furthermore, light source lamps used as general light sources emit a large amount of energy in the near-infrared wavelength region rather than visible light. Irradiating an object to be observed with wavelengths in the near-infrared wavelength region requires only shifting the spectral characteristics of commonly used infrared cut filters to longer wavelengths, and there is no technical difficulty.

FIG. 2 shows the distal end of a portion of an example of the endoscopic device according to the present invention that is inserted into a body cavity. This example is a direct view type, and the light source (
3) is guided inside by a light guide 1 and illuminates the object to be observed through a glass window 2 for illumination. Reflected light from an object to be observed is taken in through an imaging glass window 3, and is imaged by an imaging lens 4 on a light receiving surface of a self-scanning two-dimensional solid-state imaging device 5 such as a CCD or BBD. This solid-state imaging device 5 has a large number of photosensitive elements arranged in a plane. The output signal is led out through the lead wire bundle 6. This lead wire bundle 6 also includes lead wires for supplying a clock signal for operating the solid-state imaging device 5 from an external oscillator (see FIG. 3).

The light guide 1 and the lead wire bundle 6 are inserted into the sheath 7. Further, the lens 4 and the solid-state imaging device 5 are placed inside an outer case 8, which is placed at the tip of the sheath 7.

FIG. 3 △ shows the configuration of an embodiment of the externally arranged portion. Input end surface 1 of light guide 1 protruding from the end of j1 port 7
A light source 21 is placed facing a. The light source 21 emits infrared rays and visible rays, and the rays emitted from the light source pass through a rotating filter 22 and enter the entrance end surface la of the light guide 1, thereby illuminating the object to be observed. For the core of the light guide 1, since multi-component glass generally does not attenuate in the near-infrared wavelength region, it is preferable to use a handle made of fibers whose core material is made of quartz or the like, which does not attenuate even in the near-infrared wavelength region. . The rotary filter 22 is arranged so as to be rotated at a constant speed by the motor 20 at a predetermined speed. The light-receiving element 24 and the color switching signal circuit 25 constitute a switching pulse generation circuit, which detects a passing wavelength region that changes depending on the rotation angle of the rotary filter 22, and generates a driving pulse of the solid-state imaging device 5 and a color change signal from the solid-state imaging device 5. The image signals and the like that are generated are synchronized with the rotation of the rotary filter 22. That is, half mirror 2
The light reflected by the light receiving element 3 is incident on the light receiving element 24, and the output of the light receiving element 24 is supplied to the color switching signal circuit 25. The color switching signal circuit 25 includes a current amplifier and a level detection circuit, converts the output current signal of the light receiving element 24 into a voltage signal, and uses a level detection circuit to generate timing signals for blue, green, and red, respectively. Furthermore, the output of the current amplifier of such a color switching signal circuit is differentiated, and the levels are made uniform to be used as a trigger signal for the oscillation circuit 27. The signal switching circuit 28 receives the image signal led out from the imaging device 5 via the lead wire bundle 6 via the amplifier 26, and outputs it to each different output terminal in synchronization with the color type of light incident on the light guide 1. 28B, 28. It performs the operation of supplying to G and 28R. This signal switching circuit 28 uses a high-speed operating switch such as a semiconductor analog switch. The oscillation circuit 27 receives the trigger signal from the color switching circuit 25 and outputs the scanning signal of the imaging device 5 and the horizontal deflection circuit 32 and vertical deflection circuit ii! of the monitor cathode ray tube 34. 833. The horizontal deflection circuit 32 outputs the blue, red and red beams of the monitor fluoroun tube 34 in the horizontal direction, and the vertical deflection circuit 33 outputs these beams in the vertical direction. It consists of an output amplifier that swings the

Output terminals 28G, 28R and 28 of the signal switching circuit 28
Each output from frame memory 38a, 38b, 3
The green amplifier 29, red amplifier 30 and blue amplifier 3
1, respectively.

FIG. 3B is a diagram showing the configuration of still another embodiment of the externally arranged portion, in which 6' is a signal line from the solid-state imaging device;
5 is an amplifier, 36 is an A/D converter, 37 is a switching circuit that switches in synchronization with the rotary filter 22, 38a, 3
8b and 38c are memories for storing information in each wavelength range, and 39 is a TV signal processing circuit necessary for displaying on a TV monitor. In this example, information on three wavelength regions is assigned to each wavelength region in chronological order as a memo! J38a, 38b
When writing and reading to and 38c, read at the same time,
Performs single word processing suitable for TV monitors.

Memories 38a, 38b, and 38C are provided with a refresh function to read out the same signal many times. Each memo 'J38a, 38b, and 38C is composed of a plurality of memories, and can be written while being read.

FIG. 4 shows the rotating filter 22. FIG. The rotating filter 22 is equally divided into three parts 40, 41 and 42, e.g.
Part 40 is 700 nm to 300 nm (red), part 41
800 nm to 900 nm (infrared region), and the portion 42 transmits light having wavelengths of 600 nm to 700 nm (orange color). The signal switching rotation 23 is driven in synchronization with the rotation of the filter 22, and, for example, an image signal obtained by the light transmitted through the red portion 40 is supplied to the green channel via the green output terminal 28G, and the image signal is supplied to the monitor cathode ray tube 34. The image is projected as a green image on the top, and the infrared region part 4
The image signal obtained by the light transmitted through 1 is sent to the red output terminal 2.
8R, it can be displayed as a red image, and the image signal obtained by the light transmitted through the orange portion 42 can be displayed as a blue image through the blue output terminal 28B. In this case, the image signals given from the multiple illumination light wavelength ranges do not necessarily need to be displayed in the same or similar colors on the monitor cathode ray tube 34; for example, the output corresponding to the portion 40 is displayed in red,
It is naturally possible to display the portion 1 in blue and the portion 42 in green. Although there are many combinations, these combinations may be used in such a way that it is easiest to distinguish between the affected area and the normal area.

Each part of the rotating filter 22 used in the present invention can be set to various wavelength ranges as shown in Table 1. However, the combination of wavelength regions is not limited to this. In this embodiment, the incident end surface 1a is circular, but it may be formed into a slit a or a rectangular shape.

Table 1 FIG. 5 is a reflection curve diagram of a normal part and an affected part in a living body cavity. The reflection curve of the normal part is shown as A, and the reflection curve of the affected part is shown as B. Now 11. A spectral filter that passes through the β2 and l wavelength regions is used to perform spectroscopy, and the electrical signals obtained from the solid-state imaging device using the light in these wavelength regions are, for example, R (red), G (green), and B (blue), respectively. ) When an image is displayed in synchronization with the electrical signal of ), the reflection curve A of the normal part draws a substantially flat trajectory, so the reflectance of R, G, and B is constant, and as a result, the colors are mixed and become white. However, when looking at the affected area, if we draw a locus like reflection curve B and let α, β, and γ represent the reflectance in the wavelength range β1.12 and 13, the colors will be mixed at the ratio of αR + βG + γB, so that the normal white display device will be colored. The affected area marked with is clearly displayed in color. In the visible range, even if it passes through a conventional visible range R, G, and B filter, the reflection curve B is almost the same as the reflection curve B, so the difference between the normal part and the abnormal part can be identified with a display device. It is difficult.

The present invention is not limited to the above-mentioned example (many changes and modifications are possible). In the above-mentioned example, an example was explained in which images of three wavelength regions are obtained, but the present invention is not limited to this. It is not a matter of fact. Even more information can be obtained by taking many wavelength regions. In this case, currently popular TV monitors display R (red) and G (green).
, B (blue), and a four-tone image is displayed by mixing them, so a color image of three or more colors may be displayed by mixing these colors. However, it is also conceivable to store images for each wavelength region once in a frame memory and to sequentially switch over the images, read out the image signals from the memory in three wavelength regions at a time, and display them in the three primary colors on a TV monitor.

As detailed above, according to the endoscope device of the present invention, three
In the case where primary color image signals corresponding to the subject color images are sequentially obtained in time series by rotating the color separation filters,
It is possible to improve the fidelity of color balance in the process of color separation-signal transmission and one-color synthesis, which has been considered a drawback. However, the causes of the above-mentioned shortcomings have been ■ Poor blue sensitivity of solid-state imaging Yonago, ■ Difficulty in setting the color temperature of illumination light to an ideal state, ■ Problems in signal transmission paths and signal processing circuits. It is possible to eliminate various causes such as incomplete elimination of distortion, and failure to reach the ideal state of each primary color emission spectrum of CRT during the photosynthesis stage.
It has the effect of making it possible to easily and quickly distinguish between affected parts and normal parts inside a living body, and in addition, it is expected to provide more accurate detection than before.

[Brief explanation of drawings]

Fig. 1 Δ and B are diagrams showing the state of the reflection spectrum of human organs; Fig. 2 is a sectional view showing the tip of the part inserted into the body cavity of an example of the endoscope device according to the present invention; Fig. 3 A and B are diagrams showing the configuration of the parts disposed outside the endoscope device of the present invention, FIG. 4 is a diagram showing a rotary filter used in the endoscope device of the present invention, and FIG. 5 is a living body cavity. FIG. 4 is a diagram showing reflection curves for a normal part and an affected part of the body. 1... Light guide 2... Glass window for lighting 3
...Imaging glass window 4...Imaging lens 5.5a
, 5b...Solid-state imaging device 6...Lead wire bundle 6'...Signal line 7 from the solid-state imaging device...Top 8...Outer casing 9...Light passing through the lens 10...Penta Prism 11... Guicroic surface 12... Infrared wavelength region light 13... Mirror surface 14
...Light transmitting block 20...Motor 21...Light source 22...
Rotating filter 22a... Optical filter 23...
Half mirror 24... Light receiving element 25... Color switching signal circuit 26... Amplifier 27... Oscillation circuit 2
8...Signal switching circuit 28R...Red output terminal 28G...Green output terminal 28B...Blue output terminal 29...Green amplifier 30...Red amplifier 31
...Blue amplifier 32...Horizontal deflection circuit 33.
...Vertical deflection circuit 34...Monitor cathode ray tube 35...Amplifier 36...A/D converter 37...Switching circuit 38 a, 38 b, 38 c...Information storage memory 39...TV Signal processing circuit Fig. 1 400 EJOOof2θθ Sakahi (rrrn) ; l Matato (πm) Fig. 2 Procedures Amendment Written February 23, 1981 Commissioner of the Patent Office Kuro 1) Mr. Akio - Invention title Relationship with the case of the person who corrects the mirror device Patent applicant

Claims (1)

[Scope of Claims] 1. A means for illuminating an object to be observed in time series with at least one light in an infrared wavelength region and at least one light in a wavelength region different from the infrared wavelength region; An optical system is provided at the tip of the part to be inserted into the object to be observed, and receives light from the object to be observed to form an image of the object on the imaging plane. , a solid-state imaging device that converts an optical image of an object to be observed into an electrical signal; a plurality of frame memories that store electrical signals representing images of the object to be observed by light in each of the wavelength ranges outputted from the solid-state imaging device; An endoscope apparatus comprising means for receiving electrical signals selectively read from the plurality of frame memories and displaying an image.