JPH06105803A - Electronic endoscope apparatus - Google Patents

Abstract

PURPOSE:To enable the correction of a color near a specified color without affecting given color by computing a size of a first color signal relative to two color signals, second and third, to correct color of at least one of the second and third color signals by a color altering signal generated. CONSTITUTION:A color correction circuit is made up of first and second color correction circuits. An RGB color signal is subjected to a color correction with the first color correction circuit 91 and inputted into the second color correction circuit for further color correction. The RGB color signal inputted into the first color correction circuit 91 is inputted into a color altering signal generator 61 to generate a color altering signal C. Then. the signal is inputted into a coefficient device 62 indicated by a coefficient (k) to be converted into a color correction signal C with a specified size by a control signal S to be outputted from a color correction setting circuit 63. When a hue of a subject closer to R is corrected in the direction of Ye, the color correction setting circuit 63 changes over contacts of switches 64, 65 and 66 and the color correction signal C is added to a G signal selected with an adder 67 to output a correction G signal corrected through the switch 65.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic endoscope apparatus having color correction means for generating a color change signal from a reference color signal and performing color correction on other color signals.

[0002]

2. Description of the Related Art In recent years, endoscopes have come to be widely used for diagnosis and the like in the medical field and also for inspection of plants and the like in the industrial field. FIG. 6 shows a conventional electronic endoscope apparatus. The electronic endoscope apparatus shown in FIG. 6 has an electronic endoscope 1, and this electronic endoscope 1 has an elongated and flexible insertion portion 2, and a thick rear end of the insertion portion 2. A diameter operation unit 3 is connected in series. A flexible universal cable 4 extends laterally from the vicinity of the rear end of the operation section 3,
A connector 5 is provided at the tip of the cable 4.

The electronic endoscope 1 is connected via the connector 5 to a video processor 6 having a light source device and a signal processing circuit built therein. Further, a color monitor 7 is connected to the video processor 6. On the distal end side of the insertion portion 2, a rigid distal end portion 9 and a curving portion 10 adjacent to the distal end portion 9 and capable of curving toward the rear side are sequentially provided.

Also, by rotating the bending operation knob 11 provided on the operation section 3, the bending section 10 is rotated.
Can be bent to the left or right or up and down. In addition, the operation portion 3 has an insertion opening 1 that communicates with a treatment tool channel (not shown) provided in the insertion portion 2.
Two are provided. FIG. 7 shows the configuration of the signal processing system.

As shown in FIG. 7, a light guide 14 for transmitting illumination light is inserted into the insertion portion 2 of the electronic endoscope 1. The front end surface of the light guide 14 has an insertion portion 2
It is arranged at the front end portion 9 of the above, and the illumination light can be emitted from this front end portion 9. In addition, the light guide 14
The incident end side of is inserted into the universal cable 4 and connected to the connector 5.

The objective lens system 1 is attached to the tip portion 9.
5 is provided, and the solid-state imaging device 16 is provided at the image forming position of the objective lens system 15. This solid-state image sensor 1
No. 6 has sensitivity in a wide wavelength range including the visible range and the ultraviolet range to the infrared range. Signal lines 26 and 27 are connected to the solid-state image sensor 16, and the signal lines 26 and 27
27 is inserted into the insertion portion 2 and the universal cable 4 and connected to the connector 5.

On the other hand, the light source device 20 provided in the video processor 6 is provided with a lamp 21 which emits light in a wide band from ultraviolet light to infrared light. As the lamp 21, a general xenon lamp, a strobe lamp, or the like can be used. The xenon lamp and strobe lamp emit a large amount of not only visible light but also ultraviolet light and infrared light.

Electric power is supplied to the lamp 21 by a power source section 22. A rotary filter 50, which is driven to rotate by a motor 23, is arranged in front of the lamp 21. Filters that transmit light in the respective wavelength regions of red (R), green (G), and blue (B) for normal observation are arranged in the rotary filter 50 along the circumferential direction.

The rotation of the motor 23 is controlled by a motor driver 25 so that the motor 23 is driven. The light that has passed through the rotary filter 50 and is time-sequentially separated into lights in the respective wavelength regions of R, G, and B is further light guide 1.
The light is incident on the incident end of No. 4, is guided to the tip portion 9 through the light guide 14, is emitted from the tip portion 9, and illuminates an observation site or the like.

The return light from the subject (subject) such as the observation site due to the illumination light is imaged on the solid-state image pickup device 16 by the objective lens system 15 and photoelectrically converted. The solid-state image sensor 16 includes the signal line 26.
A drive pulse is applied from the driver 31 in the video processor 6 via the, and only the electric signal (video signal) corresponding to the image of the subject photoelectrically converted by the drive pulse is read out. There is.

The electric signal read from the solid-state image pickup device 16 is inputted to the preamplifier 32 provided in the video processor 6 or the electronic endoscope 1 through the signal line 27. ing. This preamp 3
The video signal amplified in 2 is input to the process circuit 33, subjected to signal processing such as γ correction and white balance, and converted into a digital signal by the A / D converter 34.

This digital video signal is processed by the select circuit 35, for example, three memories (1) 36a, memories (2) 36b, and memories corresponding to respective colors of red (R), green (G), and blue (B). (3) It is adapted to be selectively stored in 36c. R stored in the memory (1) 36a, the memory (2) 36b, the memory (3) 36c,
The G and B color signals are simultaneously read out and input to the color correction circuit 59.

In the color correction circuit 59, the R and B color signals are input to the coefficient multipliers 51 and 52, respectively. Coefficient units 51, 5
In step 2, the magnitude of the input signal is converted into a predetermined magnitude. This conversion is performed using a preset value or a value set from the outside.

The R, G, B color signals color-corrected by the color correction circuit 59 are converted into analog signals by the D / A converter 37 and output as R, G, B color signals, and an encoder is also provided. It is input to the encoder 38 and is output from the encoder 38 as an NTSC composite signal.

The R, G, B color signals or N
The TSC composite signal is input to the color monitor 7, and the color monitor 7 displays the observed region in color.

Further, the video processor 6 is provided with a timing generator 42 for generating the timing of the entire system, and the timing generator 42 synchronizes the circuits such as the motor driver 25, the driver 31, and the selection circuit 35. Has been taken.

[0017]

In the color correction method described above, color adjustment is performed by simply changing the magnitude of the R or B signal. For example, in the case of an electronic endoscope, it may be made yellowish as a whole in order to make the color look like a fiberscope. In this case, in the color correction method described above, B
This can be achieved by reducing the signal.

However, for example, in the case of dyeing blue with methylene blue or the like, in the case where the B signal is reduced as described above, the saturation of blue itself becomes small, and the dyed object becomes dark, which makes the inspection difficult. There is. Also,
If the R signal is reduced to make the red color of the mucous membrane lighter, the saturation of the blood color in bleeding etc. will also be reduced, making it difficult to distinguish between blood (fresh blood and old blood, etc.). .

Further, in the case of an electronic endoscope, at the time of inspection,
The color reproducibility of blood is important. Particularly, in the hue direction, fine adjustment is necessary. In the case of the conventional method, R
It is possible by adjusting the signals of two systems of B signal and B signal, but the adjustment is complicated because the signals of two systems are adjusted, and the colors other than the target color (in this case, the color of blood) are increased. It will change.

There is also a method (Hue adjustment) of converting the hue of each color on the color difference plane. In this case, however, the circuit becomes complicated when processing in the base band, and when only a specific color is corrected. Furthermore, the circuit becomes complicated. For example, Japanese Laid-Open Patent Publication No. 1-121034 discloses a technique for emphasizing hue, saturation, etc., but its circuit configuration is very complicated.

The present invention has been made in view of the above points, and it is possible to relatively easily correct a hue of a predetermined color that requires fine adjustment at the time of inspection so that other hues are less affected. It is an object of the present invention to provide an electronic endoscope apparatus including the means.

[0022]

According to the present invention, an electronic endoscope having an image pickup means for converting light information from a subject into an electric signal and a video signal for generating a video signal from the electric signal of the image pickup means are provided. In an electronic endoscope apparatus having a video signal processing means for performing processing, a color signal generating means for generating first, second and third color signals from the electric signal, and the first
Color change signal generating means for generating a color change signal by calculating the relative magnitudes of the color signal and the second and third color signals, and second and third color change signals based on the color change signal. By providing a color correction unit that performs color correction of at least one of the three color signals, the hue of a predetermined color that requires fine adjustment can be relatively easily corrected so that it does not affect other colors. It has become.

[0023]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 5 relate to an embodiment of the present invention.
Shows the configuration of the signal processing system of the electronic endoscope apparatus of one embodiment, FIG. 2 shows the configuration of the first color correction circuit, and FIG. 3 shows an explanatory view of the function of the color correction by the first color correction circuit. 4 shows the configuration of the second color correction circuit, and FIG. 5 shows an explanatory view of the function of color correction by the second color correction circuit.

The electronic endoscope apparatus according to the first embodiment of the present invention shown in FIG. 1 is configured by using a color correction circuit 60 having a different configuration from the color correction circuit 59 of the conventional example shown in FIG. The part of is the same as that of the conventional example of FIG. 7, and the description thereof is omitted.

The color correction circuit 60 is composed of a first color correction circuit 91 and a second color correction circuit 92. Then, the memory (1) 36a, the memory (2) 36b, the memory (3) 36
The RGB color signals read out from c are color-corrected by the first color correction circuit 91 in the color correction circuit 60, then input to the second color correction circuit 92, and further color-corrected by the D / A converter 37. Is output to. The first color correction circuit 91 will be described first.

A block diagram of the first color correction circuit 91 is shown in FIG. The RGB color signals input to the first color correction circuit 91 are input to the color change signal generator 61. The color change signal generator 61 generates the color change signal C according to the following equation.

C = R− (pG + qB) However, when R− (pG + qB) <0, C = 0 (1) Here, consider the case of p = 1 and q = 1.

When the subject color is the R primary color, G = 0, B = 0
Is. That is, C = R. Next, the subject color is yellow Y
In the case of e, R = G, B = 0 and C = RG−0. Similarly, when the subject color is magenta Mg, C = 0
Becomes

That is, when the color is R, the color change signal C has the maximum value R, and becomes smaller as it approaches Ye or Mg. Furthermore, from Ye or Mg, G, Cy, B
When the color is in the direction of, R <G + B, and thus C = 0.

Also, when R = 1, G ≧ 1/2, B ≧ 1/2, C = 0 and C approaches R as G and B become smaller. From the above, in the subject color, the value of C increases as the ratio of the R component increases, that is, the purity of the R component increases.

Next, the color change signal C output from the color change signal generator 61 is input to the coefficient unit 62 indicated by the coefficient k, and is made to have a predetermined size by the control signal S output from the color correction setting circuit 63. To be converted.

Further, the color correction setting circuit 63 controls selection of the selection switches 64, 65, 66. Here, consider a case where the hue of a subject close to R is corrected in the Ye direction (for example, the color tone is in a fiberscope-like manner). In this case, the color change signal C generated by the color change signal generator 61 may be set to a predetermined magnitude, added to the G signal, and output as a corrected G signal.

Therefore, when this correction is performed, the color correction setting circuit 63 switches the switch 64 to the contact a, the switch 65 to the contact a, and the switch 66 to the contact b as shown in FIG. The color correction signal C having the magnitude is added to the G signal selected by the adder 67, and the corrected G signal corrected through the switch 65 is output. In this case, the B signal is output as it is.

Therefore, since the saturation of the B signal is not reduced,
Even if the saturation of the B signal component is low, the blue color tone can be maintained and the subject can be prevented from becoming dark. That is, when the color correction is performed in the specific color direction, it can be performed without changing the color tones of the other color components so much.

Similarly, when correcting the hue of a subject close to R in the Mg direction, the color correction setting circuit 63 causes the switch 64 to be the contact b, the switch 65 to be the contact b, and the switch 66.
Is switched to the contact point a, the color correction signal C having a predetermined magnitude by the coefficient unit 62 is added to the B signal selected by the adder 67, and output as a corrected B signal corrected through the switch 66. The R signal itself is not corrected and is output as it is.

As described above, the color change signal C becomes large when the R signal has high purity, and Ye, Mg, G, Cy,
Since the other colors such as B become zero, the hue of the subject having a high R signal purity can be corrected by the above correction method without affecting other colors. Therefore, it is possible to perform color correction on blood or the like having a high R signal purity without affecting other subjects.

FIG. 3 shows an example of the movement of each color on the color difference plane when the above color correction is performed (when R is corrected in the Ye direction). In FIG. 3, the arrow indicates the color-corrected color change direction and the magnitude of the color change amount.

In the above explanation, p = 1 and q = 1 in the equation (1).
However, by appropriately selecting p and q, the area where the color change signal C becomes zero can be changed and the color correction range can be changed. Also in this case, R = 1,
When B = G = 0, that is, in the case of a pure R signal, C =
Since R, the correction amount is the same as in the case of p = 1 and q = 1. In the case of FIG. 2, the RGB signals input to the first color correction circuit 91 are converted into G and B signals by the first color correction circuit 91.
At least one of the signals is color-corrected and color-corrected R
The GB signal (indicated by RG1B1 in FIG. 2) is output.

In the present embodiment, if the color correction setting circuit 63 can be set arbitrarily or can be specified externally, color correction suitable for the operator can be easily performed. As described above, the RGB signal whose hue has been corrected by the first color correction circuit 91 is input to the second color correction circuit 92.

FIG. 4 is a block diagram of the second color correction circuit 92. Of the RGB signals (R, G1, and B1 in FIG. 4) input to the second color correction circuit 92, the R signal and G
The signals are the coefficient unit for R 75 and the coefficient m, which are indicated by the coefficient l.
The post-addition is performed by the adder 77 through the G coefficient unit 76 indicated by, and the averaging process is performed by the coefficient unit 78 indicated by the coefficient 1 / n.

The signal passed through the coefficient unit 78 is the switch 7
9 and the discrimination circuit 80. The input signal CE to the switch 79 and the input signal CE to the discriminating circuit 80 is expressed by the following equation.

CE = (lR + mG) / n The discriminating circuit 80 compares the magnitudes of the CE signal and the B signal and switches the switch 79. The switch 79 is switched under the following conditions.

When CE ≦ B: Switch contact a When CE> B: Switch contact b (2) The output signal of the switch 79 is adjusted to a predetermined magnitude through the coefficient unit 81 indicated by the coefficient r and added to the B signal. And output as a corrected correction B signal.

Next, the operation of the second correction circuit 92 is l =
The case of 1, m = 1 and n = 2 will be described.

In this case, CE = (R + G) / 2,
The boundary line (CE = 1) in the discrimination circuit 80 is a dotted line in FIG. 5 on the color difference plane. That is, according to (2), FIG.
On the left half surface of the dotted line, the contact b is selected for the switch 79, and on the right half surface, the contact a is selected for the switch 79. Therefore, the left half surface of the dotted line in FIG. 5 is converted by the B signal, and the right half surface is converted by the CE signal.

Here, in FIG. 5, Mg, R, Ye,
In the vicinity of G, the B signal level is almost zero, so that the B signal is hardly converted. Further, in FIG. 5, since R and G are almost zero in the vicinity of B, the CE signal is also almost zero, and conversion by the CE signal is hardly performed. From the above, in this correction, the R, G, B primary color signals and the vicinity of the Mg, Ye signals are hardly converted, and the colors near white are largely converted.

In other words, it is possible to correct the color in the vicinity of white without changing the colors of the blue-dyed subject and blood. Also in FIG. 4, if the coefficient unit 81 can be arbitrarily set or can be specified from the outside,
Color correction suitable for the operator can be easily performed.

Here, the case of l = 1, m = 1, n = 2 was described, but by appropriately selecting l, m, n, the position of the dotted line dividing the area in FIG. The value changes, and a new color correction characteristic can be given.

In the above, the color correction is performed by correcting the B signal, but the same correction method can be applied to the R signal and the G signal, or these can be combined. RGB output from the second color correction circuit 92 as described above
The signal is output as an output signal of the color correction circuit 60.

In the case of this embodiment, the two color correction circuits are arranged in series so that the output of the first color correction circuit 91 is input to the second color correction circuit 92, but the order is not limited to this. Absent. Further, depending on the purpose, only one first color correction circuit 91 or second color correction circuit 92 may be used for color correction. Also, the discrimination constants (p, q, l, m,
By combining color correction circuits with different n), more complicated and precise color correction is possible.

When the color correction is performed by the first color correction circuits 91 and 92, the color correction may be performed on the color difference plane assuming the color signal of the composite video signal or may be performed on the general color difference plane.

Further, in the case of the present embodiment, since the RGB signals can be processed as they are, there is no need for a matrix circuit such as a processing system for converting into the color difference signals, which has the advantage of simplifying the circuit.

In the above embodiment, RGB is used as the frame sequential method.
Although the method of processing the primary color signal as the original signal has been described, the present invention is not limited to the frame sequential method but can be applied to the simultaneous method in which a color filter array is mounted on the front surface of the solid-state image sensor.

In this case, when the signal processing is performed with RGB signals, the processing can be performed as in the above embodiment, but when the signal processing is performed with Y, RY and BY, Y is used. , RY, BY signals are required to be converted into RGB signals. It is obvious that the present invention can be applied to an endoscope in which a TV camera having a built-in image pickup device is attached to an optical endoscope.

[0055]

As described above, according to the present invention, it is possible to correct a color in the vicinity of a specific color without affecting a predetermined color, and to affect a predetermined color necessary for inspection. It is possible to provide a color correction circuit with less number of colors.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a signal processing system of an electronic endoscope apparatus according to an embodiment of the present invention.

FIG. 2 is a circuit diagram showing a configuration of a first color correction circuit.

FIG. 3 is an explanatory diagram of a function of color correction by a first color correction circuit.

FIG. 4 is a circuit diagram showing a configuration of a second color correction circuit.

FIG. 5 is an explanatory diagram of a function of color correction by a second color correction circuit.

FIG. 6 is an overall view of a conventional electronic endoscope apparatus.

FIG. 7 is a block diagram showing the configuration of a signal processing system of a conventional electronic endoscope apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Electronic endoscope 2 ... Insertion part 3 ... Operation part 4 ... Universal cable 5 ... Connector 6 ... Video processor 7 ... Color monitor 9 ... Tip part 14 ... Light guide 16 ... Solid-state image sensor 21 ... Lamp 36a, 36b, 36c ... Memory 37 ... D / A converter 38 ... Encoder 50 ... Rotation filter 60 ... Color correction circuit 61 ... Color change signal generator 62 ... Coefficient unit 63 ... Color correction setting circuit 64, 65, 66 ... Switch 63 ... Adder 91 ... First color correction circuit 92 ... Second color correction circuit

Claims (1)

[Claims] 1. An electronic endoscope including an image pickup means for converting optical information from a subject into an electric signal, and a video signal processing means for performing a video signal processing for generating a video signal from the electric signal of the image pickup means. An electronic endoscope apparatus having: a color signal generation unit that generates first, second, and third color signals from the electric signal; the first color signal; and the second and third colors. A color change signal generating means for calculating a relative magnitude with the signal to generate a color change signal; and a color correction for correcting at least one of the second and third color signals based on the color change signal. An electronic endoscope apparatus comprising: