JPH0145604B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an endoscope device using a solid-state image sensor. Conventionally, when observing and recording the inside of a biological cavity or a mechanical device, it has been common to use an endoscope, also called a fiberscope. An endoscope called a fiberscope has at least an imaging optical system that creates an image of the object to be examined at the distal end that is inserted into the part to be observed, and an optical image created by the imaging optical system. One end of an optical fiber bundle called an image guide transmits the image to the tip of the image guide, and one end of an optical fiber bundle called a light guide serves as an illumination member to illuminate the specimen. It is widely used to observe images magnified with a loupe, record them in photographs, or capture images with a television camera.

BACKGROUND ART In recent years, with remarkable progress in semiconductor technology, self-scanning solid-state imaging devices such as CCDs are beginning to be put into practical use, and television cameras using this type of solid-state imaging devices have already been put into practical use. Compared to image pickup tubes such as vidicon conventionally used in television cameras, this type of solid-state image sensor has the potential to be made smaller and lighter, so it is possible to incorporate the solid-state image sensor directly into the tip of the endoscope. Several attempts have been made to convert the image of the object to be examined by an imaging optical system into an electrical signal and display it on a television receiver (CRT display device) as a television image. (Tokukai Akira
51-65962, Japanese Patent Application Publication No. 49-114940, etc.).

In this case, to make the TV image displayed on the CRT color, the following methods are generally considered on the imaging side. The first method is a basic method, in which the image of the subject created by the imaging optical system is separated into three primary color images of red R, green G, and blue B.
The second method uses three separate solid-state image sensors corresponding to the primary color images, and the second method uses filters of the three primary colors Red R, Green G, and Blue B in a mosaic pattern, corresponding to each pixel that makes up the solid-state image sensor. This method multiplexes the imaging plane by coloring the images. Thirdly, in consideration of the structure of the endoscope and the peculiarities of its use, the light source side that provides illumination light to the illumination member of the endoscope, that is, the bundle of optical fibers called the above-mentioned light guide, has red, green, and blue lights, for example. In this method, three primary color filters are rotated at a predetermined rotational speed, and three primary color component images of red, green, and blue are taken out from a single solid-state image sensor in a frame-sequential manner. However, when these methods are used in endoscopes, the following drawbacks appear. The first method is the most basic and provides good images, but it is impossible to store it in a thin and small tip like an endoscope.
If the endoscope is stored, the distal end of the endoscope will become large and the use of the endoscope will be severely restricted. Second
In terms of shape, this method allows the endoscope tip to be made smaller, but since the imaging surface of the solid-state image sensor is color-divided by a mosaic-like filter of the three primary colors of red, green, and blue, the green part, which determines the resolution, It is unavoidable that the number of pixels will decrease, leading to a decrease in resolution. Especially when the tip of the endoscope is made smaller,
Since it becomes difficult to use a solid-state image sensor with a large number of pixels, a reduction in resolution becomes a particularly big problem in this case. The third method uses one solid-state image sensor in a field-sequential format and sequentially extracts the three primary color components of the image, so it is difficult to temporally register the three primary color images for relatively fast-moving objects. Problems occur and deterioration of image quality becomes inevitable.

The present invention relates to an endoscope device having an optimal imaging method for an endoscope using a solid-state image sensor, which improves the above-mentioned drawbacks by taking into consideration the structure and usage conditions of the endoscope. The tip has at least an imaging optical system that creates an image of the object to be examined, a self-scanning solid-state image sensor that converts the image formed by the imaging optical system into an electrical signal, and an illumination means that illuminates the object. The solid-state image sensor is arranged with cyan and yellow color filters alternately corresponding to each pixel constituting the solid-state image sensor, and when the illumination means illuminates the green colored light, the entire solid-state image sensor is illuminated. When an image signal corresponding to the green component of the object to be examined is extracted from the pixel and illuminated with white light by the illumination means, the cyan component of the object to be examined is detected than the pixel in which the cyan color filter of the solid-state image sensor is arranged. An image signal corresponding to the yellow component of the object to be examined is extracted from the pixel where the yellow color filter is arranged, and these image signals are electrically processed by an image signal processing device. The present invention proposes an endoscope device using a solid-state image pickup device, which is characterized in that it is processed into a color image signal and displays a color image on a display device such as a CRT display device.

The present invention will be explained in detail below using Examples.

FIG. 1 shows a schematic configuration of an endoscope apparatus according to the present invention, in which 1 is an endoscope main body, 2 is a light source device, 3 is a synchronization circuit, 4 is an image signal processing circuit, and 5 is a
An image display device such as a CRT is shown.
The distal end portion of the endoscope body 1 that is inserted into the part to be observed is equipped with an imaging optical system 12 that forms at least an image of the subject.
A self-scanning solid-state image sensor 13 typified by a CCD, etc., and a tip 15 of a light guide 14 as an illumination member for illuminating the object to be inspected are incorporated into the solid-state image sensor 13. Cyan (Cy) and yellow (Y) color filters are arranged in a mosaic pattern as shown in FIG. 2, corresponding to each constituent pixel. Note that a window glass 11 is provided at the distal end of the endoscope body 1 shown in FIG. The illumination light emitted from the tip 15 of the light guide 14 illuminates the test object through the window glass 11, and the electrical signal of the image from the solid-state image sensor 13 is transmitted through the lead wire bundle ls. The signal is transmitted to the image signal processing device 4 and displayed as an image by the display device 5. Here the lead wire bundle ls
includes lead wires and the like for supplying clock signals and the like for driving the solid-state image pickup device, and circuits for driving the CCD such as these clock signals are included in the image signal processing device 4.

On the other hand, the light source device 2 has two flash lamps 25 and 26 that can flash alternately at high speed, and one of the flash lamps 25 has a color temperature correction filter 24.
A green filter 23 is placed on the other flash lamps, and the green light and white light from these light sources is passed through a half mirror I/R cut filter 27 and sent to the light guide 14 by a condenser lens 21. The light is focused on one end surface 16.
The flash lamps 25 and 26 of this light source device are configured to blink alternately in synchronization with one field of the image by a synchronization circuit 3, but in this figure, the power to turn on the flash lamps 25 and 26 is Sources are not omitted.

In FIG. 1, as an example, depending on the order of the first field of the image, the third, fifth, etc. odd fields are illuminated by green light (flash lamp 26) as shown in FIG.
and a green filter 23), each pixel of the solid-state image sensor has cyan (Cy) and yellow (Y) color filters arranged as shown in FIG. As shown in Figure 3, the signal G of the green component of the object is extracted from both the pixel where the cyan filter is placed and the pixel where the yellow filter is placed. The signal of the green component of the object is extracted. Next, depending on the order of the second field, the 4th, 6th, etc. even fields are illuminated with white light W (blue + green + red) (made by the flash lamp 27 and the color temperature correction filter 24) as shown in FIG. Then, as is clear from the figure, the cyan component signal (Cy) of the test object is extracted from the pixel where the cyan filter in Fig. 2 is arranged, and the signal (Cy) of the cyan component of the object is extracted from the pixel where the yellow filter is arranged. A signal of the yellow component (Y) of the object to be inspected is extracted. That is, signals of cyan and yellow components of the object to be examined are obtained from the second field. Next, these green, cyan, and yellow component signals are temporarily stored in a storage device (buffer memory) included in the signal processing circuit 4, and the blue component signals are changed by cyan (-) and green, respectively. -) A red component signal is created by the green signal, and a television video signal is created by the signal processing circuit. In this case, the resolution of the blue component and red component signals of the test object is 1/2 that of the green component signal, but
The resolution of a color TV image is determined by the green component signal, so by extracting the signal as described above, the resolution of the color image will not deteriorate, and the 2-field method will allow you to Since all the color component signals are obtained, it takes 2/3 of the time compared to the previously mentioned method of sequentially extracting images of the three primary colors. The problem of target registration will be improved.

Also, in this embodiment, a case is explained in which a flash lamp that flashes in synchronization with the field is used as the light source, but a light source that rotates green and magenta filters that rotate in synchronization with the field is used as the light source. You can also do that.

As described above, according to the present invention, despite using one solid-state image sensor, resolution and image deterioration due to registration errors are significantly improved compared to the methods proposed so far, and the device is more compact. Since the distal end of the endoscope can be constructed in a manner similar to that of an endoscope, a very large effect can be achieved, especially when the shape and size of the distal end of an endoscope are subject to restrictions. In the above embodiment, a mosaic filter that corresponds to each pixel of the solid-state image sensor in a 1:1 ratio was used, but the same image processing can be achieved even if it is replaced with a stripe filter that has stripes in the vertical direction as shown in FIG. It is clear that this can be done.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram of an endoscope device according to the present invention, FIG. 2 is a plan view of a mosaic filter, and FIG.
The figure shows the spectral transmittance of a cyan filter and a yellow filter forming a mosaic filter, and the intensity of green component light extracted thereby. 1... Endoscope, 12... Imaging optical system, 13...
Solid-state image sensor, 14...Illumination means, Cy...Cyan filter, Y...Yellow filter.

Claims (1)

[Claims] 1. In an endoscope for observing and recording inside a biological cavity or a mechanical device, the distal end inserted into the biological cavity or the inside of a mechanical device, etc. has at least an imaging device that forms an image of the object to be examined. It has an optical system, a self-scanning solid-state image sensor that converts an image formed by the imaging optical system into an electrical signal, and an illumination means that illuminates the object, and the solid-state image sensor includes a solid-state image sensor. Corresponding to each pixel, cyan and yellow color filters are arranged alternately, and when the illumination means illuminates with green color light, image signals corresponding to the green component of the object are obtained from all pixels of the solid-state image sensor. When the illumination means illuminates with white light, an image signal corresponding to the cyan component of the object is extracted from the pixel in which the cyan color filter of the solid-state image sensor is arranged, and a yellow color filter is arranged. This method uses a solid-state image sensor, which is characterized by extracting image signals corresponding to the yellow component of the object from the pixels and electrically processing these image signals to form a color image. Viewing device.