JP2822632B2 - Electronic endoscope device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic endoscope apparatus, and more particularly, to an electronic endoscope apparatus capable of controlling a light amount suitable for endoscope diagnosis.

[Prior art] An electronic endoscope used for medical or industrial use includes a scope section, a processor, and a monitor device, and an insertion section in the scope section is inserted into a body cavity or the like and is built into the processor. Or, irradiate illumination light from the independent lighting device toward the observation target part, and reflect the reflected image from the observation target part.
A video signal is formed by photoelectric conversion by a solid-state imaging device such as a CCD, and the obtained video signal is read out from the imaging device and transmitted to a processor. The color display is used.

By the way, the light quantity control in the conventional electronic endoscope apparatus detects an average value of the luminance of the video signal obtained from the solid-state imaging device, and controls the illumination target unit from the illumination device so that the average value becomes a predetermined reference value. The amount of illumination light emitted toward the camera is controlled.

[Problems to be solved by the invention]

However, when the scope is inserted into the body cavity, the end of the scope may be close to the inner wall of the body cavity and a high-luminance portion may be generated in the observation target portion. However, there is a problem in that the photocell of the solid-state imaging device that irradiates a high part of the image becomes saturated and the image becomes invisible.

On the other hand, there is a light amount control method that detects the peak value of the luminance of the video signal and controls the light amount of the illumination light so that the peak value becomes a predetermined reference value. Although the problem that the photocell of the image sensor is saturated is solved, there is a problem that a dark portion is easily generated in the observation target portion, and the dark portion is difficult to see.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide an electronic endoscope apparatus that can realize light amount control that can solve the above-described problems.

[Means for solving the problem]

In order to achieve the above object, the present invention irradiates illumination light from an end of a scope toward an observation target portion, and images the illuminated observation target portion with a solid-state image pickup device built in the end of the scope to image the observation target. Video signal indicating the part,
In an electronic endoscope apparatus that displays an image indicating an observation target unit based on the video signal, an average value detection unit that detects an average value of luminance of the observation target unit based on the video signal, Peak value detection means for detecting a peak value of the brightness of the observation target portion based on the first and second reference values, which are a target value of the average value and a target value of the peak value, respectively. Second setting means, a mode changeover switch for selectively switching between a first light quantity control mode based on the detected average value and a second light quantity control mode based on the detected peak value, and the first light quantity When the control mode is selected, the control unit controls the amount of light of the observation target unit incident on the solid-state imaging device based on a deviation between the detected average value and the set first reference value.
When the light amount control mode is selected, control means for controlling the light amount of the observation target portion incident on the solid-state imaging device based on a deviation between the detected peak value and the set second reference value, It is characterized by having.

[Action]

According to the present invention, the light amount control method can be appropriately switched by the mode switching switch so that the light amount control based on the peak value can be performed when the scope is inserted and the light amount control based on the average value can be performed during normal observation. ing. In addition, since the first and second setting means can set the first reference value and the second reference value, which are the target values of the average value and the peak value, respectively, the optimum value is set for each light amount control method. It is possible to set an appropriate reference value and prevent iris hunting and the like.

〔Example〕

Hereinafter, preferred embodiments of an electronic endoscope apparatus according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a block diagram showing the overall configuration of an electronic endoscope apparatus according to the present invention. As shown in FIG. 1, the electronic endoscope device includes a scope unit 10, a processor 20, and a monitor device 30.

To the processor 20, R, G,
An illumination device for sequentially irradiating the B light to the observation target portion 14 is built in. That is, the white light from the light source 21B lit by the light source lighting circuit 21A is
The light is guided to one end 12A of the light guide 12 through the rotating filter 3 and the rotating color filter 24.

The rotating color filters 24 each have a central angle of 120 ° R,
It has three color filters of G and B and is rotated by a motor 25. This motor 25 is a synchronous signal generation circuit
By the motor control circuit 26 that inputs the synchronization signal from 27,
It is controlled to rotate at a predetermined rotation speed (for example, 20 rps). As a result, the light from the light source 21B sequentially changes at a cycle of 1/60 second through the rotating color filter 24,
The light becomes illumination light of each color of G and B, and is applied to the observation target portion 14 via the light guide 12.

An objective lens 15 and a solid-state imaging device (CCD) 16 are provided at the tip of the scope unit 10, and the objective lens 15 includes R, G, B
An image of the observation target portion 14 illuminated by each illumination light is formed on a light receiving portion of the CCD 16, and the CCD 16 is driven by a driving pulse applied from the CCD driver 28 via the signal line 17, and photoelectrically converts incident light to each of them. An RGB video signal corresponding to the illumination light is output to the signal processing circuit 29 via the signal line 18.

The signal processing circuit 29 of the processor 20 performs signal processing such as simultaneous conversion of a plane-sequential RGB video signal input from the CCD 16 and outputs the signal to the monitor device 30.

FIG. 2 is a block diagram showing details of the processor.

In the figure, a plane-sequential RGB video signal input from the CCD 16 is applied to an A / D converter 41 via a process circuit 40 having a sample hold circuit, a γ correction circuit, a clamp circuit, and the like. The A / D converter 41 converts an input RGB video signal (analog signal) into a digital signal one pixel at a time, and converts the digital signal into R, G, B field memories 42, 43, 44.
Output to

The field memories 42, 43, 44 are controlled by a memory control circuit 45. That is, the memory control circuit 45 performs the RGB control based on the vertical synchronization pulse applied from the synchronization signal generation circuit 27.
The video signals are sequentially stored in the field memories 42, 43 and 44, and R-EN pulses, G-EN pulses and B-EN pulses for updating the stored contents of the memories are output.

Sequentially written to the field memories 42, 43, 44
The RGB video signals are read out simultaneously and the D / A converters 46, 47, 48
The video signals are output from video output terminals 53, 54, and 55 via process circuits 50, 51, and 52 having a clamp circuit for adjusting the black level.

On the other hand, the outputs of the D / A converters 46, 47, 48 are applied to an iris control circuit 60. The iris control circuit 60 generates a signal for controlling the amount of illumination light based on the simultaneously converted RGB video signal, and outputs the signal to the iris motor of the iris 22 (FIG. 1).

Next, details of the iris control circuit 60 will be described.

FIG. 3 is a block diagram showing an embodiment of the iris control circuit 60.

As shown in the figure, the iris control circuit 60 mainly includes a matrix circuit 61, an average value detection circuit 62, a peak value detection circuit 63, reference value setting devices 64 and 65, a differential amplifier 66, and a mode switch 67. Have been.

The matrix circuit 61 is connected to the D / A converters 46, 47,
A GB video signal is input, and a luminance signal Y is generated based on these video signals and a predetermined coefficient.
68, and output to the average value detection circuit 62 and the peak value detection circuit 63 via the clamp circuit 69.

The average value detection circuit 62 smoothes the input luminance signal Y, outputs a signal indicating the smoothed average value (see FIG. 4A) to the contact A of the switch SW1, and the peak value detection circuit 62 inputs the signal. The peak value of the luminance signal Y is held and a signal indicating the peak value (see FIG. 4B) is supplied to the contact B of the switch SW1.
Output to

Reference value setter 64 and 65 intended for setting the reference value is a target value of the average value and the peak value is the detected respectively, switches the DC voltage V _a and V _P (see FIG. 4) shows a reference value Output to contact A and contact B of SW2.

The mode changeover switch 67 selectively switches between the light quantity control mode based on the average value and the light quantity control mode based on the peak value. When the average value light quantity control mode (contact A) is selected by the mode changeover switch 67, the switches SW1 and SW1 are switched. SW2 is switched to the contact A side in conjunction with it, and when the peak value light quantity control mode (contact B) is selected, the switch SW2 is switched.
1 and SW2 are linked and switched to the contact B side.

The signal from the switch SW1 is applied to the negative input of the differential amplifier 66 via the buffer 70 and the resistor, and the DC voltage indicating the reference value from the switch SW2 is applied to the positive input of the differential amplifier 66.

The differential amplifier 66 calculates the difference between the two input signals, amplifies the difference, and outputs the amplified signal to the drive amplifier 71. The drive amplifier 71 amplifies the input signal and outputs the amplified signal to the iris motor.

Thus, in the case of the average light amount control mode, the average value average value signal output from the detection circuit 62 is the iris 22 so that the reference voltage V _a is controlled, in the case of the peak value light quantity control mode, iris 22 is controlled such that the peak value signal outputted from the peak value detection circuit 63 becomes the reference voltage V _P.

FIG. 5 is a block diagram showing another embodiment of the iris control circuit. In addition, the same reference numerals are given to portions common to FIG. 3, and the detailed description thereof will be omitted.

As shown in the figure, the average value signal output from the average value detection circuit is applied to the negative input of the differential amplifier 74 via the buffer 72 and the resistor, and the peak value signal output from the peak value detection circuit 62 is Differential amplifier via buffer 73 and resistor
Added to 75 negative inputs.

On the other hand, the differential amplifier 74 and 75 to the positive input, and added reference voltages V _a and V _P respectively from the reference value setter 64 and 65, the difference between the respective differential amplifiers 74 and 75 are two-input signal The signal is amplified and output to the contacts A and B of the switch SW.

When the average light amount control mode is selected by the mode changeover switch 67, the switch SW is switched to the contact A side, a signal input from the differential amplifier 74 is output to the drive amplifier 71, and the peak value light amount control mode is selected. Switch SW is switched to the contact B side, and the differential amplifier
The signal input from 75 is output to the drive amplifier 71.

In this embodiment, the iris 22 is controlled to control the amount of illumination light. However, the present invention is not limited to this. For example, the CCD 1
The charge accumulation time in 6 may be controlled to control the light amount of the observation target portion substantially incident on the CCD 16.

〔The invention's effect〕

As described above, according to the electronic endoscope apparatus according to the present invention, the light amount control method based on the average value and the light amount control method based on the peak value can be appropriately used depending on the use condition of the scope. In addition, since the reference values that are the target values of the average value and the peak value to be detected are separately set, an optimum reference value can be set for each light amount control method, and iris hunting and the like can be prevented. .

[Brief description of the drawings]

FIG. 1 is a block diagram showing an overall configuration of an electronic endoscope apparatus according to the present invention, FIG. 2 is a block diagram showing details of a processor shown in FIG. 1, and FIG. 3 is a block diagram showing an iris control circuit shown in FIG. 4 (A) and 4 (B) are signal waveform diagrams used to explain FIG. 3, and FIG. 5 is a block diagram showing another embodiment of the iris control circuit. is there. 14: Observation target section, 16: Solid-state imaging device (CCD), 21B: Light source, 22: Iris, 60: Iris control circuit, 61: Matrix circuit, 62: Average value detection circuit, 63: ... peak value detection circuit, 64, 65 ... reference value setting device, 66, 74, 75 ... differential amplifier, 67 ... mode changeover switch, SW1, SW2, SW ... switch.

Claims (1)

(57) [Claims] An illumination light is radiated from an end of a scope toward an observation target portion, and an image of the illuminated observation target portion is imaged by a solid-state imaging device built in the end of the scope to obtain a video signal indicating the observation target portion. An electronic endoscope apparatus that displays an image indicating the observation target unit based on the video signal; an average value detection unit that detects an average value of luminance of the observation target unit based on the video signal; A peak value detecting means for detecting a peak value of the brightness of the observation target portion based on a first reference value and a second reference value which are target values of the average value and the peak value, respectively. And a second setting means, a mode changeover switch for selectively switching between a first light quantity control mode based on the detected average value and a second light quantity control mode based on the detected peak value, When the first light amount control mode is selected, the light amount of the observation target portion incident on the solid-state imaging device is controlled based on a deviation between the detected average value and the set first reference value, When the second light amount control mode is selected, a control for controlling the light amount of the observation target portion incident on the solid-state imaging device based on a deviation between the detected peak value and the set second reference value. Means, and an electronic endoscope apparatus comprising: