JPH09138356A - Electronic endoscope - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively reduce or suppress random noises by providing a noise suppression processing means and reproducing an optical subject image according to an image signal of one frame outputted from the means. SOLUTION: Respective color image signals of red, green, and blue of one odd field are outputted from an RGB frame buffer 24 to adders 26R, 26G, and 26B. Further, they are outputted to memories 28R, 28G, and 28B as well and temporarily written. Simultaneously, similar image signals of the respective colors which are written last time are read out of odd-field memory areas of respective colors and outputted to adders 26R, 26G, and 26B. The adders 26R, 26G, and 26B adds the current and last image signals of the respective colors together and input them to a multiplier 30, which multiplies them by a coefficient 1/2. At this time, random noises included in the current image signals of the respective colors are canceled, and consequently the image signal of the respective signals having random noises suppressed can be obtained. Then video is reproduced according to them.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic endoscope,
More specifically, it relates to improvement of an image signal processing unit of an electronic endoscope.

[0002]

2. Description of the Related Art Generally, an electronic endoscope includes a scope formed of a flexible conduit, and a solid-state image pickup device such as a CCD (charge coupled device) image sensor is provided at the tip of the scope. The image sensor is combined with an objective lens system, and a subject image captured by this objective lens system is formed on the light receiving surface of the solid-state imaging device. In addition, an optical guide made of an optical fiber bundle is inserted into the scope, the end surface of the tip portion is located at the tip of the scope of the electronic endoscope, and the other end portion is connected to the light source. When the scope is inserted into the body cavity of the patient, the front side of the objective lens system on the tip side thereof is illuminated by the light emitted from the end face of the tip part of the light guide, and thereby the image inside the body cavity of the patient is reproduced by the monitor device. .

More specifically, the solid-state image pickup device converts an optical object image formed on its light-receiving surface into an analog image signal for one frame, and the analog image signal is sequentially read by clock pulses at predetermined time intervals. To be The analog image signal read from the solid-state image pickup device is converted into a digital image signal after being subjected to predetermined image processing, and then the digital image signal is temporarily held in an appropriate frame buffer means. Next, the digital image signal for one frame read from the frame buffer means is converted into an analog image signal, then passed through a low-pass filter, amplified, and then sent to a monitor device, where the image of the optical object image described above is displayed. Reproduction is done. Note that such image reproduction can be performed by either a non-interlaced scanning method or an interlaced scanning method.

The electronic endoscope as described above is usually combined with a color monitor device so as to perform color display. In this case, CC used in the electronic endoscope
Since the number of pixels of a solid-state image pickup device such as a D image sensor is smaller than that of a normal one, a so-called frame sequential method is adopted. That is, for example, a rotary RGB color filter is interposed between the light source and the end surface of the proximal end of the light guide, and red light, green light, and blue light are sequentially emitted from the end surface of the distal end of the light guide. The subject image is sequentially formed on the light receiving surface of the CCD image sensor with red light, green light, and blue light, from which the red image signal, the green image signal, and the blue image signal are read out at predetermined time intervals. Next, the image signals of the individual colors are processed in the same manner as described above, and the subject image is reproduced as a full-color image on the color monitor device based on the processed image signals.

[0005]

In the conventional electronic endoscope as described above, the image signal read from the CCD image sensor contains various random noises in the time axis direction. For example, since the inside of the body cavity of the patient is illuminated only by the light flux emitted from the end surface of the light guide,
The light amount of the subject image formed on the light receiving surface of the CCD image sensor may fluctuate greatly, and noise caused by such a light amount fluctuation appears in the reproduced image. Further, noise due to dark current generated in the CCD image sensor and external noise also appear in the reproduced image. Needless to say, such noise itself is not so problematic in short-time observation of the monitor device, but for a doctor who requires long-term observation, it causes eye fatigue and interferes with normal diagnosis. become.

Therefore, an object of the present invention is to provide an electronic endoscope as described above, which is constructed so as to effectively reduce or suppress the random noise as described above. Is.

[0007]

According to one aspect of the present invention, solid-state image pickup means for converting an optical object image as an image signal for one frame, and one frame portion sequentially read from the solid-state image pickup means. In an electronic endoscope including a buffer unit that temporarily holds an image signal, a noise suppression processing unit that performs a noise suppression process on an image signal for one frame read from the buffer unit is provided, and the noise suppression processing unit is provided. Video reproduction of an optical subject image is performed based on the image signal for one frame output from the.

According to one aspect of the present invention described above, the noise suppression processing means is output from the buffer means and the memory means for temporarily holding the image signal for one frame previously read from the buffer means. The image signal for one frame and the image signal for the previous one frame output from the memory means may be summed up and multiplied by a coefficient 1/2. In this case, the image reproduction of the optical object image is performed based on the image signal for one frame output from the calculating means, and the buffer means is used when the image signal for the previous one frame is output from the memory means to the calculating means. The image signal for one frame this time is written in the memory means.

According to another aspect of the present invention, the noise suppression processing means outputs the noise suppression processing image signal for the previous one frame temporarily from the memory means and the buffer means. Multiply the image signal for one frame by the coefficient α (0 <α <1) and add the coefficient (1 -α) to the image signal for one frame that was output from the memory means and that was subjected to the previous noise suppression processing. It may include a calculation means for adding the product of the multiplications. In this case, the image reproduction of the optical object image is performed based on the image signal for one frame output from the calculation means, and the image signal for one frame subjected to the previous noise suppression processing from the memory means to the calculation means. At the time of output, the image signal for one frame subjected to the noise suppression processing of this time is written from the calculation means to the memory means.

In one aspect of the present invention described above, preferably, the solid-state image pickup means is configured to convert an optical object image into an image signal for each one frame of each of the three primary colors based on a frame sequential method. Each of the image signals for one frame is subjected to noise suppression processing in parallel with each other by the noise suppression processing means.

Further, according to the above aspect of the present invention, preferably, the image reproduction of the optical object image is performed by a non-interlaced scanning method. However, it is of course possible to reproduce an image by the interlaced scanning method. In this case, the image signal for one frame is divided into the image signal for one odd field and the image signal for one even field from the buffer means. The image signal for one field is subjected to noise suppression processing by the noise suppression processing means.

According to another aspect of the present invention, solid-state image pickup means for converting an optical object image into an image signal for one frame of each of the three primary colors based on a frame-sequential system, and sequentially read from the solid-state image pickup means. And buffer means for temporarily holding the image signals for one frame of each of the three primary colors, and noise suppression processing means for performing noise suppression processing on the image signals for one frame of each color read from the buffer means. However, in the electronic endoscope in which the image reproduction of the optical subject image is performed based on the image signal for one frame output from the noise suppression processing means, the noise suppression processing means performs the noise suppression processing by the previous time. A memory means for temporarily holding an image signal for one frame of each of the three primary colors, and each of the three primary colors output from the buffer means. Coefficient one frame image signal of the α
Multiplying (0 <α <1) and the image signal for one frame of each of the three primary colors output from the memory means, the coefficient (1-
α) is multiplied, and an arithmetic means for summing is added, and an image of an optical object image is reproduced based on the image signal for one frame output from this arithmetic means, and the memory means transfers to the arithmetic means. At the time of outputting the image signal for one frame subjected to the previous noise suppression processing, the image signal for one frame subjected to the current noise suppression processing is written from the calculating means to the memory means.

Further, according to another aspect of the present invention, the image signal for each one frame of the three primary colors output from the buffer means and the previous noise-suppressed three primary colors output from the memory means. It is possible to provide a motion detecting means for detecting the motion of the optical subject image based on the difference data from the image signal for each one frame, and in this case, a coefficient α depending on the motion detection amount of the motion detecting means. Can be changed. For example, the coefficient α is increased as the motion detection amount of the motion detection means increases, and the coefficient α is decreased as the motion detection amount of the motion detection means decreases.

Further, in the above-mentioned another aspect of the present invention, preferably, the image reproduction of the optical object image is performed by the non-interlaced scanning method, but of course, one frame of each color from the buffer means. Image signal for one odd field and the image signal for one even field are output separately, and noise suppression processing is performed on the image signal for each one field by noise suppression processing means to reproduce the image. Can be performed by an interlaced scanning method.

According to still another aspect of the present invention, a solid-state image pickup means for converting an optical object image into an image signal for one frame of each of the three primary colors based on a frame sequential method, and sequentially read from the solid-state image pickup means. Buffer means for temporarily holding an image signal for each one frame of each of the three primary colors, and noise suppression processing means for performing noise suppression processing on the image signal for one frame of each color read from the buffer means. In the electronic endoscope, which is provided with the image reproduction of the optical subject image based on the image signal for one frame output from the noise suppression processing means,
The noise suppression processing means temporarily stores the image signals for each one frame of the previous three primary colors that have been subjected to the noise suppression processing, and the image signal for each one frame of the three primary colors output from the buffer means. Multiplied by the coefficients α, β and γ (0 <α, β, γ <1) and the image signal for each one frame of the three noise-processed three primary colors output from the memory means. -α)
, (1 -β) and (1 -γ) are multiplied together, and the coefficient α, β, and γ can be changed according to the sensitivity characteristics of the human to the three primary colors, and output from the calculation means. A video image of an optical object image is reproduced based on the image signal for one frame, and is calculated when the image signal for each one frame of the three primary colors subjected to the previous noise suppression processing is output from the memory means to the calculating means. The image signal for one frame subjected to the noise suppression processing of this time is written from the means to the memory means.

Also in the electronic endoscope described above, the image reproduction of the optical subject image can be performed by the non-interlaced scanning method or the interlaced scanning method.

According to still another aspect of the present invention, a solid-state image pickup means for converting an optical object image into an image signal for one frame of each of the three primary colors on the basis of a frame-sequential method, and sequentially read from the solid-state image pickup means. The buffer means for temporarily holding the image signals for one frame of each of the three primary colors thus obtained, and the luminance signal and the two color difference signals are calculated based on the image signals for each one frame of the three primary colors read from the buffer means. And a noise suppression processing unit that performs noise suppression processing on the luminance signal and the two color difference signals output from the first arithmetic unit, and the luminance output from the noise suppression processing unit. In an electronic endoscope in which an image of an optical object image is reproduced on the basis of the signal and the two color difference signals, the noise suppression processing means thereby causes noise. Memory means for temporarily holding was suppressed processed previous luminance signal and two color difference signals, first
Of the luminance signal and the two color difference signals output from the arithmetic means of (1) and the luminance signal output from the memory means and the two color difference signal coefficients (1 -α) And a second arithmetic means for summing the two, and an image of the optical object image is reproduced based on the luminance signal and the two color difference signals output from the second arithmetic means. When the previous noise suppression processed luminance output and the two color difference signals are output to the second arithmetic means, the current noise suppressed luminance output and the two color difference signals are written from the second arithmetic means to the memory means. Is done.

With the electronic endoscope described above, it is possible to reproduce an image of an optical object image by either the non-interlaced scanning method or the interlaced scanning method.

According to still another aspect of the present invention, solid-state image pickup means for converting an optical object image into an image signal for one frame of each of the three primary colors based on a frame sequential method, and sequentially read from the solid-state image pickup means. The buffer means for temporarily holding the image signals for one frame of each of the three primary colors thus obtained, and the luminance signal and the two color difference signals are calculated based on the image signals for each one frame of the three primary colors read from the buffer means. And a noise suppression processing unit that performs noise suppression processing on the luminance signal and the two color difference signals output from the first arithmetic unit, and the luminance output from the noise suppression processing unit. In an electronic endoscope in which an image of an optical object image is reproduced on the basis of the signal and the two color difference signals, the noise suppression processing means thereby causes noise. The memory means for temporarily holding the previous luminance signal and the two color difference signals that have been subjected to the suppression processing, and the luminance signals and the two color difference signals output from the buffer means respectively have coefficients α, β and γ (0 <α, The coefficient (1 -α), (1 -β), and (1-) obtained by multiplying β, γ <1) and the luminance signal and the two color difference signals output from the memory means, respectively.
and a coefficient α by which the luminance output output from the buffer means is multiplied by the two color difference signals, β and γ.
The image reproduction of the optical subject image is performed based on the image signal for one frame output from the second calculation means, and the previous noise suppression processing from the memory means to the second calculation means is performed. When the luminance output and the two color difference signals are output, the current noise-suppressed luminance output and the two color difference signals are written from the second arithmetic means to the memory means.

In the electronic endoscope described above, either the non-interlaced scanning system or the in-laced scanning system can be adopted.

According to still another aspect of the present invention, a solid-state image pickup means for converting an optical object image into an image signal for one frame of each of the three primary colors based on a frame sequential method, and sequentially read from the solid-state image pickup means. Buffer means for temporarily holding an image signal for each one frame of each of the three primary colors, and noise suppression processing means for performing noise suppression processing on the image signal for one frame of each color read from the buffer means. A laser for reproducing an image of an optical object image based on an image signal for one frame output from the noise suppression processing means, and further guiding laser light to the solid-state imaging means side to perform laser processing. In the electronic endoscope provided with the processing means, the noise suppression processing means uses the noise suppression processing means to process the noise suppression processing for each one of the three primary colors. Memory means for temporarily holding a minute image signal, and an image signal for one frame of each of the three primary colors output from the buffer means multiplied by a coefficient α (0 <α <1) and output from the memory means. And a calculation means for adding the one obtained by multiplying the image signal for each one frame of each of the three primary colors by the coefficient (1 -α) to bring the coefficient α close to zero at the start of the operation of the laser processing means, while the laser processing is performed. When the means is switched from the operating state to the non-operating state, the coefficient α is maintained at “1” for a predetermined time, and the image reproduction of the optical object image is performed based on the image signal for one frame output from the calculating means. That is, at the time of outputting the image signal for one frame of each of the three primary colors subjected to the previous noise suppression processing from the memory means to the arithmetic means, the image signal for one frame subjected to the noise suppression processing this time from the arithmetic means to the memory means. Writing is performed. In this case, either the non-interlaced scanning method or the interlaced scanning method can be adopted.

[0022]

Next, various embodiments of an electronic endoscope according to the present invention will be described with reference to the accompanying drawings.

Referring to FIG. 1, a first embodiment of an electronic endoscope according to the present invention is shown as a block diagram. The electronic endoscope includes a scope 10 formed of a flexible conduit, and a C-shaped solid-state image pickup device is provided at a tip portion of the scope 10.
A CD image sensor 12 is provided, the CCD image sensor 12 is combined with an objective lens system (not shown), and a subject image captured by the objective lens system is formed on a light receiving surface of the CCD image sensor 12. Further, a light guide 14 formed of an optical fiber bundle is inserted into the scope 10, the end surface of the tip portion thereof extends to the end surface on the tip side of the scope 10, and the other end portion thereof is connected to the light source 16. In the present embodiment, the electronic endoscope is configured to reproduce a color image by the frame sequential method, and therefore, the rotary RGB color filter is provided in the light guide 14 between the light source 16 and the end surface of the light guide 14. 18 is interposed, and the light from the light source 16 is condensed on the end surface of the light guide 14 by an appropriate condensing optical lens system. In this way, the subject is sequentially illuminated with red light, green light and blue light. The rotary RGB color filter 18 is rotated at a predetermined rotation frequency, for example, 25 Hz (PAL system) or 30 Hz (NTSC system).

The rotary RGB color filter 18 is composed of a disk element, which is divided into six sector areas from the center to the outer circumference, and three sector areas are arranged every other one of them. The area is a light shielding area, and the other three sector areas are a red filter, a green filter and a blue filter, respectively. When the rotary RGB color filter 18 is rotated at, for example, 25 Hz, the time required for one rotation is 40 ms, and the illumination time for each color filter is approximately 20/3 ms. Red light (R), green light (G) and blue light (B) are emitted from the end face of the tip of the light guide 14 every 40
It is ejected sequentially for about 20 / 3ms during ms (1/25 sec),
The subject is sequentially imaged on the light receiving surface of the CCD image sensor 12 with red light (R), green light (G) and blue light (B). The CCD image sensor 12 converts the subject image of each color imaged on the light receiving surface thereof into an analog image signal for one frame, and the analog image signal of each color follows the illumination time of each color (approximately 20/3 ms). It is read from the CCD image sensor 12 for a blocking time (for example, 20/3 ms).
Strictly speaking, since the output power of each color from the color filter 18 and the spectral sensitivity characteristic of the CCD image sensor 12 are different, the red light (R), the green light (G), and the blue light (B) emit light. The illumination time is made slightly different, but the reading of the image signal of each color from the CCD image sensor 12 is performed within the same shielding time.

The reading of the analog image signal from the CCD image sensor 12 is performed by a well-known CCD drive circuit (not shown), and the analog image signal of each color is the CCD.
An analog / digital (A / D) converter 22 after undergoing predetermined image processing such as gamma correction in the process circuit 20.
Are sequentially converted into digital image signals.

The digital image signal of each color is written in the storage area of each color of the RGB frame buffer 24 by a clock pulse output from a well-known timing generator (not shown). More specifically, the red image signal for one frame is divided into odd field data and even field data, and written in the red odd field data storage area and the red even field data storage area of the RGB frame buffer 24 alternately. Also, the green image signal for one frame is written alternately into the green odd field data storage area and the green even field data storage area of the RGB frame buffer 24, and the one frame blue image signal is also written as odd field data and even number. Divided into field data,
The data is alternately written in the blue odd field data storage area and the blue even field data storage area of the RGB frame buffer 24. RGB frame buffer 2
4 is connected to adders 26R, 26G and 26B and also to memories 28R, 28G and 28B.

The electronic endoscope shown in FIG. 1 can employ either an interlaced scanning method or a non-interlaced scanning method for reproducing an image. First, the image reproduction by the interlaced scanning method will be described.

In the case of the interlaced scanning system, the RGB frame buffer 24 first outputs a red image signal for one odd field (red odd field data), a green image signal for one odd field (green odd field data), and an odd number. Blue image signals for the fields (blue odd field data) are output to the adders 26R, 26G and 26B, respectively, and memories 28R and 28G are also provided.
And 28B are also output and once written therein. More specifically, the memory 28R is provided with a red odd field memory area and a red even field memory area, and the memory 28G is provided with a green odd field memory area and a green even field memory area.
Similarly, the memory 28B is provided with a blue odd field memory area and a blue even field memory area.
The red image signal for one odd field, the green image signal for one odd field, and the blue image signal for one odd field output from the frame buffer 24 are respectively in the red odd field memory area and the memory 28 of the memory 28R.
It is written in the green odd field memory area of G and the blue odd field memory area of the memory 28B.

The red image signal for one odd field, the green image signal for one odd field and the blue image signal for one odd field from the RGB frame buffer 24 are respectively red odd field memory areas (memory 28).
R), green odd field memory area (memory 28G)
And the blue odd field memory area (memory 28B), in parallel with the writing, the red odd field memory area, the green odd field memory area and the blue odd field memory area are written one odd field previously. Minute red image signal, one odd field green image signal, and one odd field blue image signal are read out, and are added to adders 26R and 2 respectively.
It is output to 6G and 26B.

Accordingly, the adder 26R adds the red image signal for the current odd-numbered field and the red image signal for the previous odd-numbered field, and the adder 26G adds the green image signal for the current odd-numbered field. And the previous green image signal for one odd field are added, and similarly, the adder 26B adds the current blue image signal for one odd field and the previous blue image signal for one odd field. The summed red image signal, green image signal and blue image signal are input to the multiplier 30 where they are multiplied by the coefficient 1/2. At this time, the random noise included in the image signal of each color for the odd-numbered field of the previous time and the random noise included in the image signal of each color for the odd-numbered field of this time are canceled, thereby suppressing the random noise. The image signals of the respective colors of the odd-numbered fields thus obtained are obtained. In FIG. 1, a single block is shown as the multiplier 30 for convenience of illustration, but it is understood that three multipliers are provided for each color image signal in the block. It should be.

The image signals of each color for one odd field in which random noise is suppressed and output from the multiplier 30 are converted back to analog image signals by the digital / analog (D / A) converter 32, and the low pass filter (LPF) is used. ) 34, and is amplified by the amplifier (AMP) 36, and the monitor device 3
8 is output to the display screen of the monitor device 38, and video reproduction by odd field scanning is performed based on the image signal of each color for one odd field.

Subsequently, from the RGB frame buffer 24, a red image signal for one even field (red even field data), a green image signal for one even field (green even field data) and a blue image signal for one even field. (Blue even field data) is output to the adders 26R, 26G and 26B, respectively, and is also output to the memories 28R, 28G and 28B and is temporarily written therein. More specifically, the red image signal for one even field, the green image signal for one even field, and the blue image signal for one even field output from the RGB frame buffer 24 are stored in the memory 2 respectively.
The data is written in the red even field memory area of 8R, the green even field memory area of memory 28G, and the blue even field memory area of memory 28B.

The red image signal for one even field, the green image signal for one even field and the blue image signal for one even field from the RGB frame buffer 24 are respectively red even field memory areas (memory 28).
R), green even field memory area (memory 28G)
And the blue even field memory area (memory 28B), in parallel with the writing, one even field previously written from the red even field memory area, green even field memory area and blue even field memory area. Minute red image signal, one even field green image signal, and one even field blue image signal are read out, and are added to adders 26R and 2R, respectively.
It is output to 6G and 26B.

The adder 26R adds the red image signal for the current even-numbered field and the red image signal for the previous even-numbered field, and the adder 26G adds the green image signal for the current even-numbered field and the previous. And the green image signal for the even field of
Then, the blue image signal for the current even field and the blue image signal for the previous even field are added. The summed red image signal, green image signal and blue image signal are input to the multiplier 30 where they are multiplied by the coefficient 1/2. At this time, the random noise included in the image signal of each color for the even-numbered field of the previous time and the random noise included in the image signal of each color for the even-numbered field of this time are canceled, thereby suppressing the random noise. The image signals of the respective colors of the even-numbered fields thus obtained are obtained.

The image signal of each even color field for which random noise is suppressed and output from the multiplier 30 is returned to an analog image signal by a digital / analog (D / A) converter 32 and is then converted into a low pass filter (LPF). ) 34, and is amplified by the amplifier (AMP) 36, and the monitor device 3
8 and the image is reproduced by the even field scanning on the display screen of the monitor device 38 based on the image signal of each color for one even field. Thus, a full-color image is reproduced by the monitor device 38 according to the interlaced scanning method based on the image signal for one frame in which random noise is suppressed.

Output of image signals of respective colors from the RGB frame buffer 24, memories 28R, 28G and 28.
The image signals of the respective colors are read out from B, and the adders 26R, 2
The output of the image signals from 6G and 26B is controlled by the timing generator described above.

Next, the case where the electronic endoscope shown in FIG. 1 adopts the non-interlaced scanning system will be explained. From the RGB frame buffer 24, one frame of red image signal, one frame of green image signal and The blue image signals for the frames are output to the adders 26R, 26G and 26B, respectively, and the memories 28R and 28G are also provided.
And 28B are also output and once written therein. When a red image signal for one frame, a green image signal for one frame, and a blue image signal for one frame from the RGB frame buffer 24 are written to the memory 28R, the memory 28G, and the memory 28B, respectively, they are parallel to the writing. Then, the red image signal for one frame, the green image signal for one frame, and the blue image signal for one frame that were written last time are read out from those memories, and are added to the adders 26R, 26G, and 26B, respectively. Is output.

The adder 26R adds the red image signal for the current one frame and the red image signal for the previous frame, and the adder 26G adds the green image signal for the current frame and the previous frame. Minute green image signal is added, and similarly, the adder 26B adds the current one frame blue image signal and the previous one frame blue image signal. The summed red image signal, green image signal and blue image signal are input to the multiplier 30 where they are multiplied by the coefficient 1/2. At this time, the random noise contained in the image signal of each color for the previous one frame and the random noise contained in the image signal of each color for the current frame are canceled, and the random noise is suppressed. Image signals of each color for one frame can be obtained.

The image signal of each color for one frame, in which random noise is suppressed, output from the multiplier 30 is converted back into an analog image signal by the digital / analog (D / A) converter 32, and a low-pass filter (LPF). After passing through 34, the signal is amplified by an amplifier (AMP) 36 and output to a monitor device 38. On the display screen of the monitor device 38, a non-interlaced scanning method is performed based on an image signal of each color in which one frame of random noise is suppressed. The video is reproduced by.

FIG. 2 schematically shows the suppression of random noise according to the first embodiment described above. As shown in the figure, if the previous one frame image signal and the current one frame image signal each contain random noise, add both image signals and multiply by a factor of 1/2. The random noise is suppressed and eliminated from the image signal for one frame obtained by.

Referring to FIG. 3, there is shown a second embodiment of the electronic endoscope according to the present invention, in which only parts different from the block diagram of FIG. 1 are shown. That is, the entire block diagram of the second embodiment is the same as that shown in FIG. 1 except for the portion shown in FIG.
Is the same as that shown in FIG. In the second embodiment, RG
The output side of the B frame buffer 24 is connected to the adders 42R, 42G and 42B via the multiplier 40, and the output sides of these adders are the digital / analog (D / A) converters 3.
2 is connected. Also, adders 42R, 42G and 42
The output side of B is also connected to memories 44R, 44G and 44B, and the output sides of these memories are connected to adders 42R, 42G and 42B via multipliers 46R, 46G and 46B, respectively. As will be apparent from the following description, the memory 44R stores one frame of red image signal for which previous random noise is suppressed, and the memory 44G includes one frame for which previous random noise is suppressed. The green image signal is stored in the memory 44B, and similarly, the blue image signal for one frame in which random noise is suppressed is stored in the memory 44B. The multiplier 3 shown in FIG.
It should be understood that, as in the case of 0, three multipliers are included for each color image signal within a single block, shown as multiplier 40.

In the second embodiment, the red image signal for one frame, the green image signal for one frame, and the blue image signal for one frame output from the RGB frame buffer 24 are first input to the multiplier 40, Then the coefficient α
After being multiplied by (0 <α <1), adders 42R, 42
It is output to G and 42B, respectively. On the other hand, the previous one frame red image signal, the previous one frame green image signal and the previous one frame blue image signal output from the memories 44R, 44G and 44B are input to the multipliers 46R, 46G and 46B. Input, where the coefficient (1-
After being multiplied by α), it is output to the adders 42R, 42G and 42B, respectively. Thus, in each of the adders 42R, 42G, and 42B, part of the image signal of each color for the current one frame (multiplied by the coefficient α) and part of the image signal of each color for the previous one frame (coefficient (coefficient ( 1-α)
However, the random noise is suppressed in the image signal.

From each of the adders 42R, 42G, and 42B, an image signal of each color for one frame is output to the digital / analog (D / A) converter 32, where it is returned to an analog image signal, and then a low-pass filter. (LPF) 3
After passing 4, the signal is amplified by the amplifier (AMP) 36 and output to the monitor device 38. Thus, on the display screen of the monitor device 38, image reproduction by the non-interlaced scanning method is performed based on the image signal of each color in which the random noise for one frame is suppressed. On the other hand, the adder 42R,
The image signals of the respective colors for one frame output from the 42G and 42B are stored in the memories 44R, 44G and 44B.
The image signals of the corresponding color for one frame are stored in each memory, and these image signals are used to suppress random noise from the image signal of each color for the next one frame. Thus, also in the second embodiment, it is possible to eliminate random noise from the reproduced image on the monitor device 38.

FIG. 4 schematically shows suppression of random noise according to the second embodiment described above. As is clear from the figure, the coefficient α (0 <α <1) and the coefficient (0 <α <1) are included in the image signal of each color for one frame this time and the image signal of each color for one frame in which the previous random noise is suppressed. 1-
α) is multiplied respectively, and then both image signals are added to obtain the image signal of each color for one frame in which the random noise is suppressed this time. The image signal of each color for one frame in which the random noise is suppressed this time is used for delaying one frame and suppressing the random noise from the image signal of each color for the next one frame.

In the second embodiment, different from the first embodiment, one obtained by multiplying the image signal of each color for one frame in which the random noise is suppressed by the coefficient (1−α) and the current one. A coefficient α (0 <α <
Since the value obtained by multiplying 1) is added, the effect of suppressing random noise is improved as compared with the case of the first embodiment. Further, in the second embodiment, the smaller the coefficient α to be multiplied by the image signal of each color for one frame this time (that is, it may include a lot of random noise), the more S
The / N ratio is improved, but when there is no correlation between the image signal for the previous one frame and the image signal for the current one frame, for example, when the subject image has a large movement. Since the afterimage phenomenon occurs in the reproduced image and the image quality is deteriorated, it is important to set the value of the coefficient α in consideration of such factors.

In the second embodiment, the case where the image reproduction is performed by the non-interlaced scanning method has been described, but in the second embodiment, the image by the interlaced scanning method is also used as in the case of the first embodiment. It goes without saying that it can be reproduced.

FIG. 5 shows an equivalent block diagram of the block shown in FIG. As is clear from the comparison of both figures, in the equivalent block diagram of FIG. 5, the multipliers 46R, 46G and 4
Sign invertors 48R, 48G and 48B are used in place of 6B, RGB frame buffer 24 and multiplier 4
Between 0 and 0, adders 50R, 50G and 50B are added. The image signals of each color for one frame in which the random noise is suppressed, which are output from the memories 44R, 44G, and 44B, are the code invertors 48R, 48G, and 4 respectively.
After the negative image signal is output by 8B, the adder 50R,
Input to 50G and 50B. On the other hand, the image signals of each color for one frame at this time output from the RGB frame buffer 24 are input to the adders 50R, 50G, and 50B, where they are summed with the above-described negative image signal. That is, each adder 50R, 50G, 50B obtains difference data for the image signal of each color. The difference data of each color is multiplied by α in the multiplier 40 and then added by the adders 42R and 42R.
G and 42B, on the other hand, the image signals of each color for one frame in which the previous random noise is suppressed are also input from the memories 44R, 44G and 44B to the adders 42R and 42G, respectively. , 42B
Each of the image signals for one frame obtained in step 1 is the same as that obtained in the adders 42R, 42G, and 42B in FIG.

More specifically, the image signal of each color for one frame output from the RGB frame buffer 24 is F
_{Let (n)} be the image signal for one frame obtained by suppressing random noise from this image signal F _(n), and F ' _(n) . In the block diagram of FIG. ) And F
The following relation holds between (n) ′. That is, F ' _(n) = α F _(n) + (1 -α) F' _(n-1) (1) On the other hand, in the block diagram of FIG.
_The following relation holds between _(n) and F ' _(n) . That is, F ' _(n) = α (F _(n) -F' _(n-1) ) + F ' _(n-1) … (2) Enclosing Equation (1) by α is equivalent to Equation (2) I understand. In short, the block diagram shown in FIG. 3 and the block diagram shown in FIG. 5 are equivalent to each other.

In the block diagram of FIG. 3, a total of six integrators 40 (including three integrators as described above) and integrators 46R, 46G and 46B are required. In the block diagram of FIG. 5, only three integrators 40 are needed. On the other hand, in the block diagram of FIG. 3, only three adders 42R, 42G and 42B are required, whereas in the block diagram of FIG.
And 42B and adders 50R, 50G and 50B, a total of six are required. However, in general, the hardware configuration of the integrator is considerably more complicated than that of the adder and the sign inverter, so that the actual circuit configuration obtained based on the block diagram of FIG. 5 is the block diagram of FIG. The cost is significantly reduced compared to the actual circuit configuration obtained on the basis of.

Referring to FIG. 6, there is shown a third embodiment of the present invention, in which only parts different from the block diagram of FIG. 1 are shown. That is, the overall block diagram of the third embodiment is the same as that shown in FIG. 1 except for the portion shown in FIG. The block diagram of FIG. 6 is similar to the block diagram of FIG. As mentioned earlier,
In the block diagram of FIG. 5, three integrators are included in a single block, shown as integrator 40, but the coefficient α multiplied there is common, but the block of FIG. In the figure, instead of the integrator 40 of FIG.
An integrator 40R having a coefficient α and an integrator 40 having a coefficient β
G and an integrator 40B having a coefficient γ are provided, except that the block diagram of FIG. 6 is substantially the same as that of FIG. That is, the random noise suppression process performed in the block diagram of FIG. 6 is similar to the random noise suppression process performed in the block diagram of FIG. 5 (hence, the random noise suppression process performed in the block diagram of FIG. 3).

As is well known, of the three primary colors of red light, green light and blue light, green light has the highest sensitivity to humans, followed by red light and blue light. Therefore,
In the third embodiment, the accumulator 4 for green image signals is used.
The value of the coefficient β of 0G is the largest, the value of the coefficient γ of the integrator 40B of the blue image signal is the smallest, and the value of the coefficient β of the integrator 40R for the red image signal is the intermediate value. In this case, not only a random noise suppressing effect can be obtained, but also image quality deterioration such as an afterimage phenomenon can be improved.

In the third embodiment as well, similar to the case of the first embodiment, image reproduction by the interlaced scanning system is possible.

Referring to FIG. 7, there is shown a fourth embodiment of the present invention, in which only parts different from the block diagram of FIG. 1 are shown. That is, the entire block diagram of the fourth embodiment is similar to that shown in FIG. 1 except for the portion shown in FIG. The block diagram shown in FIG. 7 has basically the same configuration as the block diagram shown in FIG.

As is apparent from FIG. 7, a data conversion circuit 52 is incorporated between the RGB frame buffer 24 and the adders 50Y, 50U and 50V, and the data conversion circuit 52 outputs from the RGB frame buffer 24. One frame of red image signal (R), one frame of green image signal (G) and one frame of blue image signal (B)
Based on the luminance signal (Y) and two color difference signals (U = B -Y)
And (V = R-Y) are created, and then their luminance signals
(Y), the color difference signal (U) and the color difference signal (V) are output to the adders 50Y, 50U and 50V, respectively. on the other hand,
Luminance signal (Y) and color difference signal (U) generated from memories 44Y, 44U, and 44V based on the previous full-frame image signal for one frame and random noise suppressed.
And a color difference signal (V) are output, and the positive and negative of these signals are converted by the sign converters 48Y, 48U and 48V and then input to the adders 50Y, 50U and 50V. That is, the adder 50Y obtains the difference data (ΔY) of the luminance signal (Y), and the adder 50U obtains the difference data of the color difference signal (U).
(ΔU) is obtained, and similarly, difference data (ΔV) of the color difference signal is obtained by the adder 50V.

The difference data (ΔY), (ΔU) and (ΔV) obtained by the adders 50Y, 50U and 50V are output to the multiplier 40, where each difference data is multiplied by the coefficient α and then added. Input to the adders 42Y, 42U and 42V. On the other hand, a luminance signal generated from the memories 44Y, 44U, and 44V based on the previous full-color image signal for one frame and random noise suppressed.
(Y), the color difference signal (U) and the color difference signal (V) are added by the adder 42Y,
42U and 42V, and therefore adder 42Y,
Difference data multiplied by coefficient α at 42U and 42V
(ΔY), (ΔU) and (ΔV) are added to the previous random noise suppressed luminance signal (Y), color difference signal (U) and color difference signal (V) respectively, thereby suppressing random noise. A luminance signal (Y), a color difference signal (U) and a color difference signal (V) for one frame can be obtained.

The frame luminance signal (Y), color difference signal (U) and color difference signal (V) obtained by the adders 42Y, 42U and 42V are converted into analog signals by the digital / analog (D / A) converter 32. Transformed and then low pass filter (L
After passing through the PF 34, it is amplified by the amplifier (AMP) 36 and output to the monitor device 38. In the monitor device 38,
Luminance signal for one frame with random noise suppressed
(Y), color-difference signal (U) and color-difference signal (V), one frame of red image signal (R), one frame of green image signal (G) and one frame of blue image signal (B) ) Is created and the image is reproduced on the display screen by the non-interlaced scanning method. On the other hand, the luminance signal (Y), color difference signal (U) and color difference signal (V) for one frame obtained by the adders 42Y, 42U and 42V are also output to the memories 44Y, 44U and 44V, and are stored in the respective memories. Corresponding signals for one frame are stored, and these signals are used to suppress random noise from the luminance signal (Y), color difference signal (U) and color difference signal (V) for the next one frame.

In the fourth embodiment as well, as in the case of the first embodiment, image reproduction by the interlaced scanning method is possible.

Referring to FIG. 8, there is shown a fifth embodiment of the electronic endoscope according to the present invention, in which only parts different from the block diagram of FIG. 1 are shown. That is, the entire block diagram of the fifth embodiment is the same as that of FIG. 1 except for the portion shown in FIG.
Is the same as that shown in FIG. The block diagram of FIG. 8 is similar to the block diagram of FIG. As described above, in the block diagram of FIG. 7, three integrators are included in the single block shown as the integrator 40, but the coefficient α multiplied there is common. ,
However, in the block diagram of FIG. 8, an integrator 40Y having a coefficient α, an integrator 40U having a coefficient β, and an integrator 40V having a coefficient γ are provided in place of the integrator 40 of FIG.
Except for this point, the block diagram of FIG. 8 is similar to the block diagram of FIG. 7. That is, the random noise suppression process performed in the block diagram of FIG. 8 is similar to the random noise suppression process performed in the block diagram of FIG. 7.

As is well known, for human beings, the visual sensitivity to a luminance signal is much higher than the sensitivity to a color difference signal. Therefore, in the fifth embodiment, the coefficient α of the integrator 40Y for the luminance signal is maximized and the coefficients β and γ of the integrators 40U and 40V for the color difference signals are reduced. In this case, not only a random noise suppressing effect can be obtained, but also image quality deterioration such as an afterimage phenomenon can be improved. It should be noted that, as compared with the case of changing the coefficient values to be multiplied by the red image signal, the green image signal and the blue image signal as in the third embodiment shown in FIG. Changing the value is more effective for improving the quality of reproduced images.

In the fifth embodiment as well, similar to the case of the first embodiment, it is possible to reproduce an image by the interlaced scanning method.

Referring to FIG. 9, there is shown a sixth embodiment of an electronic endoscope according to the present invention, in which only parts different from the block diagram of FIG. 1 are shown. That is, the entire block diagram of the sixth embodiment is similar to that of FIG. 1 except for the portion shown in FIG.
Is the same as that shown in FIG. The block diagram of FIG. 9 is similar to the block diagram of FIG. That is,
In the block diagram of FIG. 9, the block diagram of FIG. 9 is substantially the same as that of FIG. 5 except that the value of the coefficient α of the multiplier 40 is variable by the motion detection circuit 54.

The motion detection circuit 54 includes adders 50R and 50G.
And 50B, the difference data of each color is evaluated to detect the degree of movement of the subject image. When the movement of the subject image is small and is close to a still image, that is, when there is a close correlation between the image signal of each color for the previous one frame and the image signal of each color for the current one frame, the multiplier 4
The value of the coefficient α of 0 is reduced, and the random noise suppression effect is further enhanced. On the other hand, when the movement of the subject image is large, that is, when the correlation between the image signal of each color for the previous one frame and the image signal of each color for the current one frame is broken, the coefficient α of the multiplier 40 The value is increased so that the afterimage in the reproduced image can be suppressed and the image quality can be improved.

The motion detecting circuit 54 is specifically shown in FIG. 10, and the motion detecting circuit 54 includes lookup tables (LUT) 56R, 56G and 56B. Look-up table (LUT) 56R, 56G and 56B
Has its input side connected to the output sides of the adders 50R, 50G and 50B, and their lookup tables 56R and 56G.
And 56B respectively have adders 50R, 50G and 5
The difference data of the red image signal, the difference data of the green image signal, and the difference data of the blue image signal from 0B are input. For example, if one pixel data of the image signal of each color consists of 8 bits, the value of one pixel data is from 0
There are 256 values up to 255. On the other hand, when one pixel data has 8 bits, the difference data also has 8 bits,
Since there are positive and negative values in the case of difference data, there are 511 different values of difference data from -255 to +255. In any case, a large absolute value of the difference data means that the movement of the subject image is large, and a small absolute value of the difference data means that the movement of the subject image is small.

Each look-up table (LUT) 56
R, 56G, and 56B are for obtaining the absolute value of the difference data input thereto, and the relationship between the input value to each lookup table and the output value therefrom is shown in the graph of FIG. Be done. As is apparent from the graph of FIG. 11, for example, when difference data having a value of +255 is input to the lookup tables 56R, 56G, and 56B, the output data value becomes 255 as an absolute value, while -255 The difference data having the value of is the lookup table 5
Even if it is input to 6R, 56G, and 56B, the value of the output data becomes 255 as an absolute value.

Further, the motion detection circuit 54 comprises comparators 58R, 58G and 58B connected to the output sides of the look-up tables 56R, 56G and 56B, respectively, and each comparator outputs the output data from the corresponding look-up table. The value of is binarized based on a predetermined threshold. Such a threshold value is set to 128, for example, and if the value of the output data from the look-up table is 128 or more, "1" is output from the comparator and the value of the output data from the look-up table is less than 128. For example, "0" is output from the comparator.

Further, the motion detection circuit 54 includes a comparator 58R,
Counters 60R, 60G and 60B respectively connected to the output sides of 58G and 58B, an arithmetic circuit 62 connected to the output sides of these counters, and a look-up table (LUT) connected to the output side of this arithmetic circuit 62. 64
And Each counter counts the number of values "1" output from the corresponding comparator, and outputs the total count value to the arithmetic circuit 62.
An average value of the total count values from R, 60G, and 60B is calculated, and such average value data is output to the lookup table 64 as movement data of the subject image. In short, the total count value (average value data) obtained from each of the counters 60R, 60G, and 60B represents the degree of movement of the subject image. The larger the total count value, the greater the movement of the subject image, and the total count value. The smaller is, the smaller is the movement of the subject image. Arithmetic circuit 62
The average value data obtained in step S4 is output to the look-up table 64, and the look-up table 64 multiplies the coefficient α by the coefficient 4 according to the size of the average value data input therein.
0 (FIG. 9).

Input data (average value data described above) to the look-up table 64 and output value (coefficient α) from the input data.
The relationship between and is shown in the graph of FIG. FIG.
As is clear from the graph of
As the input data to 4 increases, the coefficient α output from it also increases stepwise. Thus, when the movement of the subject image is small, effective random noise suppression is performed. On the other hand, when the movement of the subject image is large, the afterimage in the reproduced image is suppressed and the image quality is improved. In FIG. 12, the coefficient α output from the look-up table 64 is increased stepwise as the input data to the look-up table 64 is increased. However, the increase of the coefficient α is linear or curved. It may be one.

The lookup table 56 shown in FIG.
Instead of R, 56G, and 56B, it is possible to use a lookup table having a relationship shown in the graph of FIG. 13, and in this case, the comparators 58R and 58 of FIG.
G, 58B are not needed. This is because in the lookup table shown in FIG. 13, the difference data is binarized together with the absolute value. That is,
When the difference data value is -128 or less, the output value is "1". When the difference data value is in the range of -128 to +128, the output value is "0" and the difference data value is When it is +128 or more, the output value is "1".

Even in the sixth embodiment, it is possible to reproduce an image by the interlaced scanning method as in the case of the first embodiment.

Referring to FIG. 14, there is shown a seventh embodiment of the electronic endoscope according to the present invention, and the construction of the entire block diagram of the electronic endoscope is substantially the same as that shown in FIG. However, in the seventh embodiment, the laser processing means 66 is combined with the electronic endoscope, and the lesion area in the body cavity is observed by the electronic endoscope while the laser processing means 66 is used to observe the lesion area. When the laser processing means 66 is operated, the value of the coefficient α of the multiplier 40 is made to approach zero.

More specifically, the laser processing means 66 includes a laser irradiation device 68, a laser drive control circuit 70 for driving the laser irradiation device 68, and the laser drive control circuit 7.
And an operation switch 72 for performing 0 operation. A light guide 74 extends from the laser irradiation device 68 and is guided into the scope 10 so that a laser is emitted from the tip of the scope 10. The operation switch 72 for operating the laser drive control circuit 70 is connected to the multiplier 40, and when the operation switch 72 is turned on as shown in the time chart of FIG. 15, the value of the coefficient α of the multiplier 40 becomes zero. Can be approached to. On the other hand, immediately after the operating switch 72 is switched from ON to OFF, the value of the coefficient α of the multiplier 40 is maintained at "1" for a predetermined short time.

Regardless of the operation of the laser processing means 66,
When the value of the coefficient α of the multiplier 40 is a constant value, when the operation switch 72 is turned on and the laser is irradiated from the laser irradiation device, the CCD image sensor 12 is immediately saturated,
The display screen of the monitor device 28 immediately becomes white and it becomes difficult to see the image. However, in the seventh embodiment, the value of the coefficient α of the multiplier 40 is brought close to zero at the same time when the operation switch 72 is turned on, so that the display screen of the monitor device 28 immediately becomes blank. Can be avoided. Immediately after the operation switch 72 is switched from on to off, the value of the coefficient α changes for a predetermined short time.
Since it is maintained at "1", the display screen of the monitor device 28 can quickly return to a normal image from the pure white state.

In the above-described embodiment, red light, green light and blue light are used as the three primary color lights in order to reproduce a full color image. However, as the other three primary color lights, yellow light,
It is also possible to use magenta light and cyan light.

[0074]

As is clear from the above description, according to the present invention, random noise is suppressed in a reproduced image obtained by an electronic endoscope, so that even if the observation is performed for a long time, the ocular characteristics of a doctor can be improved. Fatigue is reduced, and the effect that normal diagnosis can be exerted is obtained. In addition, random noise can be effectively suppressed without deteriorating the image quality of a reproduced image even for a moving subject image.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a first embodiment of an electronic endoscope according to the present invention.

FIG. 2 is a schematic diagram for explaining random noise suppression by the electronic endoscope shown in FIG.

FIG. 3 is a partial block diagram partially showing a second embodiment of the electronic endoscope according to the present invention.

FIG. 4 is a schematic diagram for explaining random noise suppression by the electronic endoscope shown in FIG.

FIG. 5 is an equivalent block diagram of the block diagram shown in FIG.

FIG. 6 is a partial block diagram partially showing a third embodiment of the electronic endoscope according to the present invention.

FIG. 7 is a partial block diagram partially showing a fourth embodiment of the electronic endoscope according to the present invention.

FIG. 8 is a partial block diagram partially showing a fifth embodiment of the electronic endoscope according to the present invention.

FIG. 9 is a partial block diagram partially showing a sixth embodiment of the electronic endoscope according to the present invention.

10 is a detailed diagram of the motion detection circuit shown in FIG.

11 is a graph showing a relationship between an input value to the difference data lookup table shown in FIG. 10 and an output value from the lookup table.

12 is a graph showing a relationship between an input value to the motion data type look-up table shown in FIG. 10 and an output value from the look-up table.

13 is a graph showing a relationship between an input value to a lookup table of a different type from the lookup table for difference data shown in FIG. 10 and an output value from the lookup table.

FIG. 14 is a block diagram showing a seventh embodiment according to the present invention.

FIG. 15 is a time chart used to explain a main part of the seventh embodiment shown in FIG.

[Explanation of symbols]

 10 Scope 12 CCD Image Sensor 14 Light Guide 16 Light Source 18 Rotating RGB Color Filter 20 CCD Process Circuit 22 Analog / Digital (A / D) Converter 24 RGB Frame Buffer 26R / 26G / 26B Adder 28R / 28G / 28B Memory 30 Multiplier 32 Digital / Analog (D / A) converter 34 Low-pass filter (LPF) 36 Amplifier (AMP)

Claims (23)

[Claims] 1. A solid-state image pickup means for converting an optical object image into an image signal for one frame, and a buffer means for temporarily holding image signals for one frame sequentially read from the solid-state image pickup means. In the electronic endoscope, the noise suppression processing means for performing noise suppression processing on the image signal for one frame read from the buffer means is provided, and based on the image signal for one frame output from this noise suppression processing means. An electronic endoscope in which the image of the optical subject image is reproduced. 2. The electronic endoscope according to claim 1, wherein
Memory means for temporarily holding the image signal for one frame previously read from the buffer means by the noise suppression processing means, image signal for one frame output from the buffer means, and output from the memory means And a calculation means for multiplying the image signal for the previous one frame by which the coefficient is multiplied by 1/2, and based on the image signal for one frame output from this calculation means, Image reproduction is performed, and at the time of outputting the previous one-frame image signal from the memory means to the arithmetic means, the current one-frame image signal is written from the buffer means to the memory means. A characteristic electronic endoscope. 3. The electronic endoscope according to claim 1, wherein:
The noise suppression processing means temporarily holds the image signal for the previous one frame subjected to the noise suppression processing by the noise suppression processing means, and the image signal for one frame output from the buffer means has a coefficient α (0 < and a calculation means for adding the product multiplied by α <1) and the product obtained by multiplying the image signal for one frame subjected to the noise suppression processing of the previous time output from the memory device by the coefficient (1 -α). An image of the optical object image is reproduced based on the image signal for one frame output from the calculating means, and the image for one frame subjected to the previous noise suppression processing from the memory means to the calculating means is performed. An electronic endoscope, wherein the image signal for one frame subjected to the noise suppression processing of this time is written from the arithmetic means to the memory means at the time of outputting a signal. 4. The electronic endoscope according to any one of claims 1 to 3, wherein the solid-state image pickup means forms an image of an optical object image for one frame of each of three primary colors based on a frame sequential method. An electronic endoscope, which is configured to be converted as a signal, in which image signals for one frame of each of these three primary colors are subjected to noise suppression processing in parallel with each other by the noise suppression processing means. 5. The electronic endoscope according to claim 1, wherein the image reproduction of the optical object image is performed by a non-interlaced scanning method. . 6. The electronic endoscope according to any one of claims 1 to 4, wherein an image signal for one frame from the buffer means is an image signal for one odd field and an image for one even field. The signal is separately output, and the image signal for each field is subjected to noise suppression processing by the noise suppression processing means, and image reproduction of the optical object image is performed by an interlaced scanning method. Endoscope. 7. A solid-state image pickup means for converting an optical object image into an image signal for each one frame of each of the three primary colors based on a frame sequential method, and one frame for each of the three primary colors sequentially read from the solid-state image pickup means. Buffer means for temporarily holding the image signal of, and noise suppression processing means for performing noise suppression processing on the image signal for one frame of each color read from the buffer means,
In the electronic endoscope in which the image of the optical object image is reproduced based on the image signal for one frame output from the noise suppression processing means, the noise suppression processing means performs the noise suppression processing of the previous time. A memory means for temporarily holding an image signal for each one frame of each of the three primary colors, and an image signal for each one frame of each of the three primary colors output from the buffer means are multiplied by a coefficient α (0 <α <1) And a calculation means for adding the one obtained by multiplying the image signal for each one frame of each of the three primary colors output from the memory means by a coefficient (1 -α), and one frame output from this calculation means Image reproduction of the optical object image is performed based on the image signal of one minute, and the image signal of one frame subjected to the previous noise suppression processing is output from the memory means to the arithmetic means. An electronic endoscope, wherein the writing of this noise suppression processed one frame of the image signal to the memory means is carried out from the calculation means. 8. The electronic endoscope according to claim 7, wherein
Based on the difference data between the image signal of each one frame of each of the three primary colors output from the buffer means and the image signal of each one frame of each of the three primary colors subjected to the previous noise suppression processing output from the memory means. An electronic endoscope characterized in that a motion detecting means for detecting the motion of the target subject image is provided, and the coefficient α can be changed according to the motion detection amount of the motion detecting means. 9. The electronic endoscope according to claim 8, wherein:
As the motion detection amount of the motion detection means increases,
An electronic endoscope, wherein the coefficient α is increased and the coefficient α is decreased as the motion detection amount of the motion detection means decreases. 10. The electronic endoscope according to claim 7, wherein the image reproduction of the optical subject image is performed by a non-interlaced scanning method. . 11. The electronic endoscope according to claim 7, wherein an image signal for one frame of each color and an image signal for one odd field are output from the buffer means. The image signals for the fields are separately output, and the image signals for one field are subjected to noise suppression processing by the noise suppression processing means,
An electronic endoscope, wherein the image reproduction of the optical object image is performed by an interlaced scanning method. 12. A solid-state image pickup means for converting an optical object image into an image signal for each one frame of three primary colors based on a frame sequential method, and one frame of each of the three primary colors sequentially read from the solid-state image pickup means. And a noise suppression processing means for performing noise suppression processing on the image signal for one frame of each color read from the buffer means. The noise suppression processing means In an electronic endoscope in which the image reproduction of the optical object image is performed based on the output image signal for one frame, each frame of the previous three primary colors subjected to noise suppression processing by the noise suppression processing unit. Memory means for temporarily holding a minute image signal and one frame for each of the three primary colors output from the buffer means. The image signal of the image signals for the respective frames for which the coefficients α, β, and γ (0 <α, β, γ <1) are multiplied, and for each one frame of the three noise-processed three primary colors output from the memory means. The image signal includes a calculation means for adding the coefficients (1 -α), (1 -β) and (1 -γ) to each other, and the coefficients α, β and γ are human sensitivity characteristics to three primary colors. The image of the optical object image is reproduced based on the image signal for one frame output from the arithmetic means, and the noise suppression processing from the memory means to the arithmetic means is performed. An electronic endoscope, wherein the image signal for one frame subjected to the current noise suppression processing is written from the calculating means to the memory means at the time of outputting the image signal for one frame of each of the three primary colors. 13. The electronic endoscope according to claim 12, wherein the image reproduction of the optical object image is performed by a non-interlaced scanning method. 14. The electronic endoscope according to claim 12, wherein an image signal for one frame of each color is divided into an image signal for one odd field and an image signal for one even field from the buffer means. The electronic endoscope is characterized in that the image signal for each one field is subjected to noise suppression processing by the noise suppression processing means, and image reproduction of the optical object image is performed by an interlaced scanning method. 15. A solid-state image pickup means for converting an optical object image into an image signal for one frame of each of the three primary colors based on a frame sequential method, and one frame of each of the three primary colors sequentially read from the solid-state image pickup means. Buffer means for temporarily holding the image signal of, and a first calculating means for calculating a luminance signal and two color difference signals based on the image signals of one frame of each of the three primary colors read from the buffer means, Noise suppression processing means for performing noise suppression processing on the luminance signal and the two color difference signals output from the first arithmetic means, and based on the luminance signal and the two color difference signals output from the noise suppression processing means. In an electronic endoscope in which video reproduction of the optical subject image is performed, before the noise suppression processing means performs noise suppression processing by the noise suppression processing means. Memory means for temporarily holding the luminance signal and the two color difference signals, and the luminance signal and the two color difference signals output from the first computing means multiplied by a coefficient α (0 <α <1). A second arithmetic means for summing the luminance signal output from the memory means and two color difference signals multiplied by a coefficient (1 -α), and the luminance output from the second arithmetic means. Image reproduction of the optical object image is performed based on the signal and the two color difference signals, and at the time of the previous noise suppression processed luminance output and two color difference signal output from the memory means to the second arithmetic means. An electronic endoscope, wherein the current noise-suppressed luminance output and writing of two color difference signals are performed from the second arithmetic means to the memory means. 16. The electronic endoscope according to claim 15, wherein the image reproduction of the optical object image is performed by a non-interlaced scanning method. 17. The electronic endoscope according to claim 15, wherein an image signal for one frame of each color is separately output from the buffer means into an image signal for one odd field and an image signal for one even field. Then, the luminance signal and the two color difference signals are calculated by the first calculation means based on the image signals for each one field, and the noise suppression processing means performs noise suppression processing on the brightness signal and the two color difference signals. In addition, the electronic endoscope is characterized in that the image reproduction of the optical subject image is performed by an interlaced scanning method. 18. A solid-state image pickup means for converting an optical object image into an image signal for each one frame of each of the three primary colors based on a frame sequential method, and one frame for each of the three primary colors sequentially read from the solid-state image pickup means. Buffer means for temporarily holding the image signal of, and a first calculating means for calculating a luminance signal and two color difference signals based on the image signals of one frame of each of the three primary colors read from the buffer means, Noise suppression processing means for performing noise suppression processing on the luminance signal and the two color difference signals output from the first arithmetic means, and based on the luminance signal and the two color difference signals output from the noise suppression processing means. In an electronic endoscope in which video reproduction of the optical subject image is performed, before the noise suppression processing means performs noise suppression processing by the noise suppression processing means. Memory means for temporarily holding the luminance signal and the two color difference signals, and coefficients α, β and γ (0 <α, β, γ <for the luminance signal and the two color difference signals output from the buffer means, respectively. 1) and the luminance signal and the two color difference signals output from the memory means are multiplied by the coefficients (1 -α), (1 -β) and (1 -γ), respectively. And a second computing means, wherein the coefficient α by which the luminance output output from the buffer means is multiplied is made larger than the coefficients β and γ by which the two color difference signals are multiplied. Video reproduction of the optical object image is performed based on the output image signal for one frame, and the luminance output and the two color difference signals from the memory unit to the second arithmetic unit are subjected to the previous noise suppression processing. Is output from the second computing means, the memo An electronic endoscope, wherein the writing of this noise suppression processing luminance output and two color difference signals to the means takes place. 19. The electronic endoscope according to claim 18, wherein the image reproduction of the optical object image is performed by a non-interlaced scanning method. 20. The electronic endoscope according to claim 18, wherein an image signal for one frame of each color is separately output from an image signal for one odd field and an image signal for one even field from the buffer means. Then, the luminance signal and the two color difference signals are calculated by the first calculation means based on the image signals for each one field, and the noise suppression processing means performs noise suppression processing on the brightness signal and the two color difference signals. In addition, the electronic endoscope is characterized in that the image reproduction of the optical subject image is performed by an interlaced scanning method. 21. A solid-state image pickup means for converting an optical object image into an image signal for one frame of each of the three primary colors based on a frame sequential method, and one frame of each of the three primary colors sequentially read from the solid-state image pickup means. And a noise suppression processing means for performing noise suppression processing on the image signal for one frame of each color read from the buffer means. The noise suppression processing means In the electronic device, the image of the optical object image is reproduced based on the output image signal for one frame, and further the laser processing means for guiding the laser beam to the solid-state imaging means side to perform the laser processing. In the endoscope, the image signal for each one frame of the previous three primary colors that has been subjected to the noise suppression processing by the noise suppression processing means. The memory means for temporarily holding the image signal for one frame of each of the three primary colors output from the buffer means multiplied by a coefficient α (0 <α <1) and the three primary colors output from the memory means. Each of the image signals for one frame is multiplied by a coefficient (1 -α) multiplied by a calculating means, and the coefficient α approaches zero at the start of operation of the laser processing means, while the laser processing When the means is switched from the operating state to the non-operating state, the coefficient α is maintained at “1” for a predetermined time, and the image of the optical object image is generated based on the image signal for one frame output from the calculating means. Reproduction is performed, and when the image signal for one frame of each of the three primary colors subjected to the noise suppression processing of the previous time is output from the memory unit to the arithmetic unit, the noise suppression of this time from the arithmetic unit to the memory unit is performed. An electronic endoscope, wherein the writing of the processed one frame of the image signal is performed. 22. The electronic endoscope according to claim 21, wherein the image reproduction of the optical subject image is performed by a non-interlaced scanning method. 23. The electronic endoscope according to claim 21, wherein an image signal for one frame of each color is divided into an image signal for one odd field and an image signal for one even field from the buffer means. The electronic endoscope is characterized in that the image signal for each one field is subjected to noise suppression processing by the noise suppression processing means, and image reproduction of the optical object image is performed by an interlaced scanning method.