JP2003135392A - Electronic endoscope system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform a display while emphasizing a specified color component of areas corresponding to recesses for an electronic endoscope system. SOLUTION: A processor 100 reads a red picture element signal, a green picture element signal and a blue picture element signal for one frame portion from a scope 10. When the signal level of a specified picture element is lower than an average signal level value of an adjacent surrounding picture element, the signal level values of dichromatic pixel signals excepting the pixel signal of which the signal level value is highest regarding the specified pixel are reduced by a color balance processing unit 126. Thus, a color image wherein the strongest color component is emphasized is displayed on the screen of a monitor device 200.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention provides a solid-state image pickup device at the tip of a scope to generate a video color signal corresponding to an image of a subject such as an internal organ, and the subject is displayed on the screen of a monitor device based on the video color signal. The present invention relates to an electronic endoscope device that reproduces a color image.

[0002]

2. Description of the Related Art In recent years, electronic endoscope devices are mainly used for reproducing color images, and as a result, in the medical field using electronic endoscope devices, as a new medical examination method based on color image reproduction. Dye endoscopy and other methods have been developed. For example, as an auxiliary diagnostic method for endoscopic diagnosis, an inspection method is known in which an appropriate dye solution is applied to the inner wall of the stomach or the large intestine to emphasize the subtle unevenness of the mucous membrane and facilitate observation of its morphology. ing.

More specifically, the inner wall of the stomach and the inner wall of the large intestine show a reddish orange color as a whole, making it difficult to observe the morphology of the fine irregularities. In such a case, when a bluish dye solution that exhibits a clear color contrast to reddish orange, such as an indigo carmine solution, is spread on the mucosal wall through the forceps holes of the scope, the dye solution becomes mucosal. It tends to collect in the concave portions of the wall, but tends to be excluded from the convex portions of the mucous membrane wall, so that the subtle unevenness form of the mucous membrane wall is very easy to observe due to the color contrast.

However, in the above-mentioned dye endoscopy method, it is necessary to prepare a dye which is harmless to the human body and is inexpensive, and because the dye is spread, the examination time becomes long and the patient's pain increases. Or, there is a problem that the mucous membrane wall cannot be observed in its original state immediately after the pigment application. In order to improve this problem, recently, as disclosed in Japanese Patent Application Laid-Open No. 2001-25025, an electronic endoscope apparatus capable of reproducing a color image with a color contrast as if dye-sprayed by image processing is considered. Has been.

Specifically, the signal level value of a specific pixel is compared with the average signal level value of eight pixels around it, and when the signal level value of the specific pixel is low, the corresponding part of the subject is depressed from the surroundings. It is determined that the red pixel signal and the green pixel signal are reduced, and the color balance changing process for emphasizing the blue color is performed. As a result, the color image reproduced on the monitor device exhibits a color contrast as if the blue dye solution was sprinkled.
The monitor device can switch and display either the color image subjected to the color balance changing process or the normal color image.

However, in the electronic endoscope apparatus as described above,
Since it is premised on observing depressions in areas where the red-orange component is relatively strong, such as the stomach inner wall, when observing bluish areas such as venous blood vessels, the areas that appear blue on the screen are all depressions. However, there is a problem that it is difficult to determine whether the blood vessel is a venous blood vessel.

[0007]

SUMMARY OF THE INVENTION In view of the above problems, it is an object of the present invention to obtain an electronic endoscope apparatus having a color balance changing processing function capable of clearly reproducing and displaying even a bluish part.

[0008]

An electronic endoscope apparatus according to the present invention generates a video color signal based on a plurality of color pixel signals for one frame obtained from a solid-state image pickup device provided at the tip of a scope. An electronic endoscope device for displaying a reproduced color image on a screen of a monitor device based on the video color signal, and comparing means for comparing signal level values of individual pixels of a plurality of color pixel signals with each other, The signal level value of the color pixel signal determined to have the highest signal level value by the means is maintained, and the signal level of the remaining color pixel signals other than the color pixel signal determined to have the highest signal level value by the comparison means. The most main feature is to include a color balance changing unit that can change the color balance of the reproduced color image by reducing the value.

In the above electronic endoscope apparatus, the color balance changing means defines the pixel compared by the comparing means as a specific pixel, and the signal level value of the specific pixel for the remaining color pixel signals is 8 pixels in the vicinity thereof. The signal level value of the specific pixel is reduced only when it is lower than the average signal level value.

In the above electronic endoscope apparatus, the color pixel signals specifically include primary color red pixel signals, green pixel signals, and blue pixel signals.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows a first electronic endoscope apparatus according to the present invention.
It is a block diagram showing an embodiment. The electronic endoscope device is
An electronic scope (hereinafter, referred to as a scope) 10 having a flexible tube 20, a video signal processing processor (hereinafter, referred to as a processor) 100 for an electronic endoscope that is detachably attached to the scope 10, and is connected to the processor 100. And a monitor device 200 that is operated.

A light guide member 12 formed of an optical fiber bundle is inserted into the scope 10 up to the tip 20a of the flexible tube, and the base end of the light guide member 12 is attached to the processor 100 when the scope 10 is attached to the processor 100. Is optically connected to the light source 102 provided in the. The light source 102 is a white light source lamp such as a xenon lamp or a halogen lamp.

A diaphragm 112 is provided on the light emitting side (left side in the figure) of the light source 102. The diaphragm 112 has its opening adjusted by a diaphragm adjusting circuit (not shown), whereby the illumination light supplied to the light guide member 12 is supplied. The amount of light is appropriately adjusted.

In the present embodiment, since the field sequential method is adopted to reproduce a color image, a rotary color filter 114 is provided further on the light guide member 12 side of the diaphragm 112. The color filter 114 has a disk shape, and a red filter that transmits only a red light component included in white light, a green filter that transmits only a green light component, and a blue filter that transmits only a blue light component are arranged in the circumferential direction. They are evenly spaced along. Light-blocking regions are provided between the color filters. The color filter 114 is rotated at a constant speed, and the white illumination light supplied from the light source 102 passes through the respective color filters to become red (R) illumination light, green (G) illumination light, and blue (B) illumination light. Converted sequentially.

Red illumination light that has passed through the color filter 114,
The green illumination light or the blue illumination light is condensed on the incident end face 12a of the light guide member 12 by the condenser lens 116,
Further, it is guided to the flexible tube tip portion 20a by the light guide member 12. By rotating the color filter 114 at a constant speed in this manner, red illumination light, green illumination light, and blue illumination light are intermittently emitted from the flexible tube distal end portion 20a for a certain period of time, and a subject located in front of it is emitted. For example, the inner wall X of the digestive organ is sequentially illuminated with the illumination light of each color.

An image sensor 14 composed of a solid-state image sensor, such as a CCD, is provided at the flexible tube tip portion 20a, and this image sensor 14 is combined with an objective lens system 16. The three-color illumination light is reflected by the subject and imaged on the light receiving surface of the CCD by the objective lens system 16. While the subject is illuminated by the illumination light of each color, the image sensor 14 produces an analog electrical signal for one frame of the optical subject image of each color,
That is, it is photoelectrically converted into an analog pixel signal, and this analog pixel signal is converted into an analog image signal in the subsequent light-shielding period.
Read from. As a result, the analog pixel signals corresponding to the respective color illumination lights are sequentially read out for one frame.

The analog pixel signals of the three colors read from the image sensor 14 are sequentially input to the CCD process circuit 120 of the processor 100, and here, the processing according to the characteristics of the image sensor 14 and the optical characteristics of the scope 10, for example, is performed. Clamp processing, sample hold processing, gamma correction processing, white balance correction processing, contour enhancement processing, amplification processing, and the like are performed. The three-color analog pixel signals processed by the CCD process circuit 120 are sent to the A / D converter 122, where they are converted into, for example, 8-bit digital pixel signals, and then written into the frame memory 124 and temporarily stored. To be done. Therefore, only one frame of red digital pixel signal, green digital pixel signal and blue digital pixel signal are stored in the frame memory 124.

The digital pixel signal for one frame is the number of pixels of pixel data according to a signal level value represented by, for example, 256 gradations for each of a large number of pixels arranged in a matrix on the light receiving surface of the image sensor 14. This signal level value includes luminance information and color density information on the three primary colors of light. The higher the signal level value, the higher the brightness (brighter) and the lower the color density (the lighter the color).
It is shown that. When an uneven subject is imaged, since the concave portion is darker than the surroundings, the signal level value of the pixel corresponding to the concave portion is relatively small, and conversely, the signal level value of the pixel corresponding to the convex portion is relatively small. Grows to.

In FIG. 2, one frame of red digital pixel signals stored in the frame memory 124 is arranged in an m × n matrix to form 8-bit red pixel data r.
_{11 to} r _mn , and each red pixel data r ₁₁
˜r _mn indicates the level value of the corresponding red pixel signal. Figure 2
As shown in, the reading of the individual red pixel data from the frame memory 124 is performed according to the line reading direction and the pixel reading direction. Specifically, the red pixel data r _{11 to} r _1n included in the first line are read pixel by pixel along the pixel reading direction, and when the reading of all pixel data of the first line is completed, the red line data is written in the second line. The included red pixel data r _{21 to} r _2n are read out pixel by pixel along the pixel reading direction. Similarly, red pixel data up to the m-th line is read.

Red pixel data r₁₁~ R_mnIs read
At the same time, the green pixel data g₁₁~ G _mnAnd the blue pixel
Data b₁₁~ B_mnAre sequentially read by the same method.

In the processor 100 of this embodiment, one of a color balance change processing mode for displaying a pseudo dye-dispersed color image in which the color balance of red, green, and blue is changed, and a normal mode for displaying a normal color image. One of them can be selected, and the mode selection is set by a mode switch SW of the operation panel 118 provided on the surface of the processor 100 or a predetermined key KEY of an external input device (here, keyboard) 300. In the initial state immediately after turning on the power, the normal mode is automatically selected.

When the normal mode is selected, the three-color pixel data read simultaneously from the frame memory 124 is output to the D / A converter 142 without any signal level value being updated in the color balance change processing unit 126. To be done. The three-color pixel data is converted into an analog signal by the D / A converter 142 and sent to the video process circuit 144. The video process circuit 144 includes a color encoder, in which a luminance signal, a color difference signal, and a chroma signal obtained by modulating the color difference signal are generated from a three-color analog pixel signal, and an NTSC in which a luminance signal, a chroma signal, and a synchronization signal are further multiplexed. An analog video color signal such as a standard composite video signal is generated.

The analog video color signal is processed by the processor 1.
00 to the monitor device 200. Monitor device 2
In 00, a color subject image is reproduced in the normal color image display area on the screen based on the analog video color signal. The color image reproduced here has a color balance very close to the color balance when the subject illuminated by white light is viewed with the naked eye.
White balance adjustment is done in 4.

An external input device 300 such as a keyboard and a mouse is connected to the processor 100, and character information such as a patient name input from the external input device 300 and an observation date and time obtained from a timer circuit (not shown) is input to the system control circuit 150. Is converted into a character pattern signal and output to the video process circuit, where it is added to the three-color pixel data. As a result, the character information is displayed on the screen of the monitor device 200 together with the reproduced color image of the optical subject image.

On the other hand, when the color balance change processing mode is set, the red pixel data, the green pixel data and the blue pixel data are stored in the color balance change processing unit 1.
26, and undergoes color balance change processing. The color balance change processing unit 126 is a programmable integrated circuit such as a PLD (Programmable Logic Decoder).
vice).

The color balance changing process will be described. First, the red pixel data, the green pixel data, and the blue pixel data are input to the comparison circuit 130, and the R signal level reduction circuit 140r and the G signal level reduction circuit 140 are also input.
It is input to the g and B signal level reduction circuit 140b. When the comparison circuit 130 detects the color pixel data having the highest signal level value among the three color pixel data for the same pixel, the remaining two color pixel data excluding the color pixel data having the highest signal level value are R In the signal level reduction circuit 140r, the G signal level reduction circuit 140g, or the B signal level reduction circuit 140b, the signal level value is reduced only when the signal level value is lower than the average signal level value of the neighboring pixels. As a result, the color balance of each pixel is changed.

For example, when the color pixel data having the highest signal level value is the red pixel data, the red pixel data is output as it is without being updated in the R signal level reduction circuit 140r. The green pixel data has its signal level value reduced only when the signal level value is lower than the average signal level value of the neighboring pixels in the G signal level reduction circuit 140g.
The signal level value of the blue pixel data is reduced only when the signal level value is lower than the average signal level value of the neighboring pixels in the B signal level reduction circuit 140b.

The red pixel data, the green pixel data and the blue pixel data that have passed through the color balance change processing unit 126 are connected to the D / s connected to the color balance change processing unit 126.
It is input to the A converter 142, converted into an analog pixel signal here, and then output to the video process circuit 144.

In the video process circuit 144, a color video signal is generated based on the three-color pixel data subjected to the color balance change processing, and the color balance change processed image with the color balance changed is displayed on the monitor device 200. .

As described above, in the color balance change processed image displayed on the screen of the monitor device 200, for example, when the blue component is the strongest for the predetermined pixel, the remaining two red components and the green component are suppressed. The blue component is relatively emphasized. In a pixel having a strong red component, the blue component and the green component are suppressed and the redness is further enhanced. Therefore, in the color balance change processed image,
The red color is further emphasized in a portion corresponding to an arterial blood vessel having a strong red component, and the bluish color is further emphasized in a portion corresponding to a venous blood vessel having a strong blue component. In addition, since a pixel having a signal level value lower than that of the surrounding area has a higher degree of enhancement, color contrast is increased, and delicate irregularities such as the inner wall of the stomach and the inner wall of the large intestine can be emphasized. Therefore, in a normal image, a lesion such as an early-stage cancer, which tends to be overlooked and whose color change is scarce, is emphasized and becomes easy to see, and a lesion can be detected earlier more easily than before.

The system control circuit 150 is a microcomputer for controlling all operations of the processor 100, including a central processing unit (CPU), a read-only memory (ROM) for storing programs and parameters for executing various routines, A writable / readable memory (RAM) for temporarily storing data and the like, and an input / output interface (I / O) are provided.

The timing generator 152 generates various control clock pulses based on the basic clock pulse obtained from the system control circuit 150,
Each circuit of the scope 10 and the processor 100 is operated by these control clock pulses. Specifically, reading of analog pixel signals from the image sensor 14, signal processing of the CCD process circuit 120, sampling of the A / D converter 122, and color balance change processing unit 1
26, the operation of the D / A converter 142, the encoding process of the video process circuit 144, and the like.

The operation panel 118 is attached to the outer wall surface of the housing of the processor 100, and in addition to the above-described mode changeover switch SW, a switch for manually adjusting the white balance, the amount of light, etc., and a switch for setting various modes. It has a plurality of. Moreover, the power supply circuit 15 is provided on the side thereof.
A main power button 156 for switching ON / OFF of No. 4 is provided. The power supply circuit 154 is connected to a commercial power supply (not shown), and when the main power supply switch 156 is turned on, power is supplied to each circuit of the processor 100, the light source 102 and the scope 10, and the processor 100 and the scope 10 are in an operable state.

FIG. 3 is a detailed block diagram of the comparison circuit 130. The comparison circuit 130 includes a delay device 1302 and six comparators 1311, 1312, 1313, 1314, 131.
5 and 1316 and three AND circuits 1321, 13
22 and 1323 and three NOT circuits 1331, 1
332 and 1333. The red pixel data, the green pixel data, and the blue pixel data of the same pixel are simultaneously input to the delay device 1302, and the respective color pixel data are R, G, B signal level reduction circuits 140r, 14 described later.
It is delayed by an amount obtained by subtracting the processing time in the comparison circuit 130 from the time required for the subtraction value calculation processing in 0 g and 140 b.

Red pixel data and green pixel data are input to the first comparator 1311, and their magnitudes are compared. If the red pixel data is larger, the output value is'
1 ', output value is'0' if green pixel data is larger
Becomes Red pixel data and blue pixel data are input to the second comparator 1312, and the magnitudes of the two are compared. If the red pixel data is larger, the output value is "1",
If the blue pixel data is larger, the output value is "0". First comparator 1311 and second comparator 1312
Is output to the AND circuit 1321, and if the two input values are "1", the output of the AND circuit 1321 is "1",
If either one is "0", the output will be "0". A
The NOT circuit 1331 is connected to the ND circuit 1321,
Here, the input value is inverted, that is, the output (a) is "1" if the input is "0", and the output (a) is if the input is "1".
Will be '0'.

That is, the first comparator 1311, the second comparator 1312, the AND circuit 1321, and the NOT circuit 13
It is determined by 31 whether or not the red pixel data corresponds to the color pixel data having the highest signal level value among the three color pixel data. If the red pixel data has the highest signal level value among the three color pixel data, NOT is determined. The output (a) of the circuit 1331 becomes "0", and when the red pixel data is the second or highest signal level value among the three-color pixel data, the output (a) of the NOT circuit 1331 becomes "1". . The output (a) is sent to the R signal level reduction circuit 140r.

Similarly, the third comparator 1313, the fourth comparator 1314, the AND circuit 1322, and the NOT circuit 1
Based on 332, it is determined whether the green pixel data corresponds to the color pixel data having the highest signal level value among the three color pixel data. If the green pixel data has the highest signal level value, the output (b) of the NOT circuit 1332 becomes '0', and if the green pixel data has the second highest or lowest signal level value, the output of the NOT circuit 1332 (b). )
Becomes '1'. The output (b) is the G signal level reduction circuit 1
Sent to 40g.

Similarly, the fifth comparator 1315 and the sixth comparator 1315
The comparator 1316, the AND circuit 1323, and the NOT circuit 1333 determine whether or not the blue pixel data corresponds to the color pixel data having the highest signal level value among the three-color pixel data. If the blue pixel data has the highest signal level value, the output (c) of the NOT circuit 1333 is "0".
If the blue pixel data has the second highest or lowest signal level value, the output (c) of the NOT circuit 1333 becomes "1". The output (c) is sent to the B signal level reduction circuit 140b.

Next, the configuration and operation of the R signal level reduction circuit 140r will be described in detail with reference to FIG. FIG. 4 is a detailed block diagram of the circuit configuration of the R signal level reduction circuit 140r. The G signal level reduction circuit 140g and the B signal level reduction circuit 140b have the same configuration as the R signal level reduction circuit 140r, and the description thereof is omitted here. The R signal level reduction circuit 140r weights the specific pixel and the signal level values of the surrounding eight pixels adjacent to the specific pixel, and sets the value obtained by the product-sum operation as the signal level value of the central specific pixel. Perform spatial filtering.

The R signal level reduction circuit 140r includes two one-line delay units D1 and D2 connected in series with each other.
Equipped with. The output terminal of the red pixel data read from the frame memory 124 is connected to the input terminal of the first one-line delay device D1 and the input terminal of the first adder AD1, and the output terminal of the first one-line delay device D1. Is connected to the input terminal of the second one-line delay device D2 and the input terminal of the second adder AD2, and the output terminal of the second one-line delay device D2 is connected to the input terminal of the third adder AD3. It When the red pixel data is input, each one-line delay device D1 and D2 delays and outputs the red pixel data by a time corresponding to the transfer time for one line.

Further, a set of one pixel delay devices DL1 and DL2 connected in series are connected to the output terminal of the frame memory 124 for red pixel data. That is, the input terminal of the first one-pixel delay device DL1 is connected to the output terminal of the red pixel data of the frame memory 124, and the output terminal of the first one-pixel delay device DL1 is the input of the second one-pixel delay device DL2. Connected to the terminal. Each one pixel delay device DL
When the red pixel data is input, 1 and DL2 delay the output by a time corresponding to the transfer time for one pixel and output the data.

Similarly, a third one-pixel delay device DL3 and a fourth one-pixel delay device DL4 are sequentially connected to the output terminal of the first one-line delay device D1, and the second one-line delay device D4.
A second one pixel delay device DL5 and a sixth
The one-pixel delay device DL6 is sequentially connected, and the color pixel data is output with a delay corresponding to the transfer time of one pixel in each of the one-pixel delay devices DL3, DL4, DL5, and DL6.

For example, the red pixel data r _{11 to} r _mn (see FIG. 2) from the frame memory 124 in the above-described order.
Is read, it is input to the R signal level reduction circuit 140r pixel by pixel. For example, at the stage when the red pixel data r ₃₃ is input from the red pixel data output terminal of the frame memory 124, the sum of the pixel data r ₁₁ , r ₁₃ , r ₃₁ and r ₃₃ is stored in the coefficient unit 1821 which will be described later. 182
The sum of the pixel data r ₁₂ , r ₂₁ , r ₂₃ and r ₃₂ is input to 2 and the pixel data r ₂₂ is input to the coefficient unit 1823.

That is, the coefficient units 1821, 1822 and 1
The nine red pixel data respectively input to 823 are
The 3 × 3 matrix red pixel data extracted from the red pixel data arranged in the m × n matrix shown in FIG. 2 is configured, and the red pixel data input to the coefficient unit 1823 is , Coefficient units 1821 and 182
It is surrounded by the red pixel data input to No. 2. In other words, the eight red pixel data r ₁₁ , r ₁₂ , r ₁₃ , r ₂₁ , r ₂₃ , r ₃₁ , which are input to the coefficient units 1821 and 1822,
r ₃₂ and r ₃₃ become the neighboring surrounding pixel data with respect to the red pixel data r ₂₂ input to the coefficient unit 1823.

A coefficient unit 182 is provided at the subsequent stage of each adder, and a fixed value of "-1/8" is set in the coefficient unit 182 as a weighting coefficient for the first coefficient unit 1821 and the second coefficient unit 182. 1822 and a third coefficient unit 1823 in which the weighting coefficient “1” is set. First coefficient unit 18
21 is an output signal of the first adder AD1, that is, an output terminal of the red pixel data of the frame memory 124,
The signal obtained by adding the outputs from the one-pixel delay device DL2, the second one-line delay device D2, and the sixth one-pixel delay device DL6 is input, and this input is multiplied by the weighting coefficient “−1/8”. Output to the adder 184. The second coefficient unit 1822 includes a first one-pixel delay unit DL1 and a first one-line delay unit D1.
A signal obtained by adding the outputs from the first, fourth one-pixel delay unit DL4 and the fifth one-pixel delay unit DL5 is input, and this input is multiplied by the weighting coefficient “−1/8” and output to the adder 184. To do. The output of the third one-pixel delay unit DL3 is input to the third coefficient unit 1823, and this input is multiplied by the weighting coefficient “1”, that is, the same value is output to the adder 184. The input pixel data of the coefficient units 1821, 1822, and 1823 are updated in the pixel reading order at each pixel transfer time.
The adder 184 has coefficient units 1821, 1822 and 18
All the outputs of 23 are added, and the result is clipped by the clipping circuit 1
Output to 86.

Thus, the two one-line delay units D1 and D1
And D2, 6 single pixel delays DL1-DL6, coefficient multiplier
The signal level of the central pixel is
Difference between the bell value and the average signal level value of its neighboring pixels Δ
R is calculated. That is, as shown in FIG.
Level of red pixel data of 9 pixels represented by matrix
Each value is r₁₁, R₁₂, ..., r₃₂, R₃₃To
And the signal level values are each multiplied by a weighting factor.
Then, the total sum is calculated. At this time, the signal level of the center pixel is
Bell value r_{twenty two}Is always multiplied by the weighting factor '1',
Each signal level value of the surrounding pixels has a negative weighting coefficient of "-1/8".
Is multiplied. As a result, the red pixel data of the center pixel
r_{twenty two}And red pixel data r of its neighboring pixels₁₁, R₁₂,
r₁₃, R _{twenty one}, R_{twenty three}, R₃₁, R₃₂And r₃₃Arithmetic mean of
And red color difference data ΔR are calculated.

The clip value of the clip circuit 186 is set to 0, and whether the difference data ΔR is positive or negative is determined. If the difference data ΔR is greater than or equal to the clip value 0, the output value is 0, and the difference data ΔR is less than the clip value 0.
That is, when it is a negative value, the difference data ΔR which is the input value
Is output as is. As described above, the two one-line delay units D1 and D2 and the six one-pixel delay units DL1 to DL are provided.
6, coefficient unit 182, adder 184 and clip circuit 1
Reference numeral 86 has a function as a comparison unit that compares the signal level value of the specific pixel with the average signal level value of the adjacent surrounding pixels.

A level reduction coefficient k is set in the coefficient unit 188 by the system control circuit 150, and when the difference data ΔR or 0 output from the clipping circuit 186 is input to the coefficient unit 188, the level reduction coefficient k is added to the input value. Are multiplied and output to the AND circuit 190.

The level reduction coefficient k is set to "0" when the normal mode is set, and is set to an appropriate positive value such as "20" when the pseudo dye spraying mode is set. Since the output of the clipping circuit 186, that is, the difference data ΔR is a negative value or 0, the output of the coefficient multiplier 188 is a negative value or 0.

The output of the coefficient multiplier 188 and the output (a) of the comparison circuit 130 are input to the AND circuit 190. As described above, the output (a) of the comparison circuit 130 is '0' if the red pixel data is the highest signal level value among the three color pixel data, and is '0' if the red pixel data is the second highest or lowest signal level value. 1 '. Therefore, when either one of the output of the coefficient unit 188 and the output (a) of the comparison circuit 130 is 0, the output of the AND circuit 190 becomes “0”, and the output of the coefficient unit 188 is a negative value. If both are present and the output (a) of the comparison circuit 130 is '1', the product of the two, that is, the output value of the coefficient unit 188 is directly used in the AND circuit 19
The output is 0.

As described above, the comparison circuit 130 is provided with the delay device 1302, and the delay device 1302 is
Output from the coefficient unit 188 and output of the comparison circuit 130 (a)
The output timing of the output (a) of the comparison circuit 130 is delayed so that the input timings of the same pixel for the AND circuit 190 and This delay time is
Processing time from the one-pixel delay unit DL1 of the R signal level reduction circuit 140r to the coefficient unit 188, that is, the subtraction value'k
・ From the time required for the subtraction value calculation process to calculate ΔR ′,
This corresponds to the time obtained by subtracting the processing time in the comparison circuit 130.

The output of the AND circuit 190 and the output of the one-pixel delay device DL3 are input to the adder 192, and the sum of them is output. That is, from the red pixel data of the central pixel,
Absolute value of product of difference data ΔR and level reduction coefficient k | ΔR
k | is subtracted. The adder 192 has a function as a color balance changing unit that changes the signal level value of the color pixel signal.

The red pixel data R _ij output from the R signal level reduction circuit 140r is expressed by the following equation (1).
The parameters i and j are conditions 1 ≦ i ≦ m, 1 ≦
It satisfies j ≦ n.

[0055]

[Equation 1]

When the input red pixel data r _ij is the color pixel data having the second highest signal level value or the lowest signal level value and ΔR <0, the data to be added to the input red pixel data r _ij Since “k · ΔR” is a negative value as described above, the level value of the output red pixel data R _ij is lower than that of the input red pixel data r _ij . On the other hand, when the input red pixel data r _ij is the color pixel data having the highest signal level value, or when ΔR ≧ 0, the output red pixel data R _ij is the input red pixel data r _ij.
The value is equal to.

In short, when the color balance change processing mode is selected and the red digital pixel signal has the second highest or lowest signal level value, the R signal level reduction circuit 140r performs the signal level reduction processing on the red digital pixel signal. Is performed, that is, when the specific color signal level value of the central pixel is lower than the pixel average value of the adjacent surrounding pixels (ΔR <0), it is determined that the area corresponds to the concave portion of the subject, and The color signal level value is reduced and output.

On the other hand, when the color balance change processing mode is not selected, the level reduction coefficient k is set to 0, so that the above signal level reduction processing is substantially invalidated in the coefficient unit 188 and the signal level value of the central pixel is It is output from the R signal level reduction circuit 140r without any change. Similarly, when the red digital pixel signal has the highest signal level value, similarly, the output (a) of the comparison circuit 130 becomes "0", so that the signal level reduction processing is substantially invalidated in the AND circuit 190. It Further, when the color signal level value of the central pixel is the same as or higher than the pixel average value of the adjacent surrounding pixels (ΔR ≧ 0), similarly, the difference data ΔR becomes 0 in the clipping circuit 186, that is, the flat portion of the subject. Alternatively, the signal level reduction processing is considered to be substantially invalid because it is regarded as a portion corresponding to the convex portion.

The G signal level reduction circuit 140g performs the same processing on the green pixel data as the R signal level reduction circuit 140r, and the B signal level reduction circuit 140b performs the same processing on the blue pixel data as the R signal level reduction circuit 140r. To do.

As described above, when the color balance changing processing mode is selected, when the image of a subject having irregularities is picked up, the levels of the remaining two color components except the strongest color component are reduced only for the pixels corresponding to the concave portions. The level of the strongest color component is relatively increased.

Therefore, the color contrast of the concave portion is emphasized in the reproduced color image. In particular, the larger the amount of depression at the portion corresponding to the pixel is, the value'k.ΔR '(or'k.ΔR' that should be subtracted from the signal level value.
G'or'k · ΔB ') becomes large, and the color component of the corresponding portion in the reproduced color image is further emphasized.

The level reduction coefficient k is automatically set to 0 when the mode selector switch SW is OFF, that is, when the normal mode is selected, and is set to a predetermined value when the mode selector switch SW is ON, that is, when the color balance change processing mode is selected. To be done. The level reduction coefficient k is a parameter that determines the degree to which the signal levels of the remaining two color components are reduced, and is set to '20' in the present embodiment, but is not limited to this value and is not limited to this value. When using the endoscope device, it is possible to change the value from the external input device 300 according to the operator's preference.

FIG. 5 is a flow chart showing a level reduction coefficient setting routine executed in the system control circuit 150. This level reduction coefficient setting routine is executed by turning on the main power switch 156 of the processor 100.
Started by N.

First, in step S102, it is determined whether or not the mode changeover switch SW is ON. If the mode changeover switch SW is OFF, in step S104 a predetermined key K of the external input device 300 is further determined.
It is determined whether EY is ON. If either one of the mode switch SW and the key KEY is ON, the color balance changing processing mode is set in step S106, the level reduction coefficient k is set to "20" in step S108, and the process returns to step S102. If it is determined that both the mode switch SW and the key KEY are OFF, the normal mode is set in step S110, the level reduction coefficient k is set to "0" in step S112, and the step S10 is performed.
Return to 2.

In this way, by setting either one of the mode changeover switch SW and the key KEY to ON,
It is possible to easily switch and display the color balance change processed image or the normal image on the screen of the monitor device 200.

As described above, according to the electronic endoscope apparatus of the first embodiment, it is possible to display the concave portion by emphasizing the strongest color component relatively for the pixel having the lower signal level value than the surroundings. , Can perform accurate diagnosis efficiently.
Further, conventionally, the color component to be emphasized is fixed to blue, but in the present embodiment, since red or green can also be emphasized, the disadvantage that only the blue component is emphasized and the venous blood vessels and the like are hard to see is solved. .

FIG. 6 shows a second electronic endoscope apparatus according to the present invention.
It is a figure which shows embodiment and is a block diagram of the whole electronic endoscope apparatus. The electronic endoscope apparatus of the second embodiment is different from that of the first embodiment in that the image pickup method is a simultaneous method instead of a frame sequential method, but other configurations are the same as those in the first embodiment. Yes, the same components are given the same reference numerals,
The description is omitted.

Since the image pickup system is the simultaneous system, the processor 500 is not provided with the rotating color filter, and the light source 10 is not provided.
The white illumination light emitted from 2 is guided to the subject X as it is. The image sensor 514 includes a CCD in which a complementary color color chip filter is arranged on the light receiving surface, and the analog pixel signal read from the image sensor 514 is a complementary color signal. The analog pixel signal is passed through the CCD process circuit 120 to A /
Converted to a digital pixel signal by the D converter 122,
Further, after being converted into primary color red digital pixel signals, green digital pixel signals, and blue digital pixel signals in the RGB converter 123, they are sequentially transferred to the frame memory 124 by one.
Only the frames are written. The primary color red digital pixel signals, green digital pixel signals, and blue digital pixel signals read from the frame memory 124 are output to the color balance change processing unit 126. The processing after the color balance change processing unit 126 is the same as in the first embodiment.

As described above, also in the electronic endoscope apparatus of the second embodiment, similar to the first embodiment, the pixel having a signal level value lower than that of the surroundings is relatively emphasized in the strongest color component to form the concave portion. Can be highlighted.

[0070]

As described above, the electronic endoscope apparatus of the present invention can emphasize the strongest color component of the pixel corresponding to the concave portion, and therefore has the advantage of enabling accurate diagnosis. is there.

[Brief description of drawings]

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

FIG. 2 is a schematic diagram showing red digital pixel signals to be input to a color balance change processing unit shown in FIG. 1 arranged in a matrix.

FIG. 3 is a detailed block diagram of a comparison circuit in the processor shown in FIG.

FIG. 4 is a detailed block diagram of an R signal level reduction circuit in the processor shown in FIG.

FIG. 5 is a flowchart showing a level reduction coefficient setting routine executed in the system control circuit of the processor.

FIG. 6 is a block diagram showing an electronic endoscope apparatus according to a second embodiment of the present invention.

[Explanation of symbols]

10 Scope 14 Image sensor (solid-state image sensor) 100 processors 126 Color balance change processing unit 130 comparison circuit 140r R signal level reduction circuit 140g G signal level reduction circuit 140b B signal level reduction circuit 150 system control circuit 200 monitor

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Claims (3)

[Claims] 1. A video color signal is generated based on a plurality of color pixel signals for one frame obtained from a solid-state imaging device provided at the tip of a scope, and a color reproduced on a screen of a monitor device based on the video color signal. An electronic endoscope apparatus for displaying an image, wherein for each pixel of the plurality of color pixel signals, a comparing unit that compares signal level values with each other, and the comparing unit determines that the signal level value is the highest. By maintaining the signal level value of the color pixel signal and reducing the signal level values of the remaining color pixel signals other than the color pixel signal determined to have the highest signal level value by the comparison means, the reproduced color image An electronic endoscope apparatus, comprising: a color balance changing unit capable of changing a color balance. 2. The color balance changing means defines the pixel compared by the comparing means as a specific pixel, and the signal level value of the specific pixel for the remaining color pixel signals is an average signal level of eight pixels in the vicinity of the specific pixel level. The electronic endoscope apparatus according to claim 1, wherein the signal level value of the specific pixel is reduced only when the value is lower than the value. 3. The electronic endoscope apparatus according to claim 1, wherein the color pixel signals include a red color pixel signal, a green color pixel signal and a blue color pixel signal of primary colors.