JPH0793702B2 - Image signal processing circuit for endoscope - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an image signal processing circuit for an endoscope that adjusts the brightness of a color image picked up by an endoscope.

[Prior Art] Generally, in an image signal processing circuit, the brightness of an image is adjusted by changing the gain of the image signal and the amount of illumination light. Here, in order to continuously change the brightness, an element such as a slide volume that can continuously change the output is used as the brightness setting element. here,
A slide volume that can continuously vary the output requires a movable member, but this movable member has a drawback that durability is deteriorated, and it is difficult to make accurate fine adjustments by setting the movable member. . Furthermore, the movable member requires a part of the device which is open to the outside, which results in incomplete drip-proofness. this is,
This is a problem in the case of an endoscope image signal processing circuit which is often operated by a hand wet with water. Further, in the case of an image signal processing circuit for an endoscope, it is necessary to prevent the internal circuit from being affected by chemicals or the like, and complete dripproofness is required.

[Problems to be Solved by the Invention] As described above, in the conventional image signal processing circuit for an endoscope, the brightness of an image is adjusted by using an element that requires a movable member such as a slide volume. There was a problem in terms of durability and reliability.

The present invention has been made in view of these problems, and an object thereof is to improve the durability and reliability of an image signal processing circuit for an endoscope whose brightness can be adjusted.

[Means for Solving the Problems] According to the present invention, the gain of an image signal captured using an endoscope and the amount of illumination light for endoscope imaging are varied to obtain the image signal. The image signal processing circuit for an endoscope that adjusts the brightness of an image detects a switch that adjusts the brightness of the image and the operation of this switch, and when the switch is operating, it is only a predetermined value at regular intervals. Means for generating a digitally changing brightness setting signal, adjusting means for adjusting the brightness of the image based on the brightness setting signal, and enabling the switch to be actuated by pressing the outer surface And a drip-proof member that protects the surface of the switch in a watertight manner.

[Operation] This device detects the operation of the setting switch that sets the brightness of the image, generates a digitally changing brightness setting signal, and adjusts the brightness of the image based on this signal. The durability and reliability of the image signal processing circuit for an endoscope can be improved.

[Embodiment] An embodiment of an image signal processing circuit for an endoscope according to the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the configuration of this embodiment. Here, it will be described as an image signal processing circuit for an endoscope image pickup apparatus having a solid-state image pickup element built in at the tip of the endoscope. In such a case, the image signal processing circuit is integrated with the light source unit. The endoscope 10 is a light guide 16 including an optical fiber bundle that transmits the illumination light emitted from the light source unit 12 to illuminate the subject to the tip, and the optics of the subject obtained by the objective lens 18 at the tip of the endoscope. It has a CCD 20 as a solid-state image pickup device for picking up an image. The light source unit 12 has a lamp 22 that causes the illumination light to enter the light guide 16, and a front surface of the lamp 22 is provided with a diaphragm 24 for adjusting the illumination light. The output image signal of the CCD 20 is supplied to the video processing circuit 26 in the light source unit 12, further input to the automatic gain adjustment (AGC) circuit 28 to adjust the gain, and then supplied to the color monitor 14 and displayed. The CCD 20 is assumed to perform color imaging by a frame sequential method, and although not shown in the drawing, a red (R), green (G), and blue (B) component are sequentially arranged on the front surface of the lamp 22. A color filter is provided. This allows
The CCD 20 sequentially outputs R, G, B color component image signals for each imaging period.

On the other hand, the front panel of the light source unit 12 is provided with brightness setting switches 30a and 30b. Brightness setting switch 30
Unlike the conventional example, a and 30b are key switches which are covered with a drip-proof cover made of rubber or the like and are turned on only while being pressed, as shown by a broken line in FIG. The brightness setting switches 30a and 30b are switches for instructing increase and decrease of image brightness, respectively. The parts corresponding to the brightness setting switches 30a and 30b on the drip-proof cover are up,
Letters such as down are written. Brightness setting switch 30
The a and 30b are connected to the key scan circuit 32. The CPU 34 is connected to the key scan circuit 32, and the output of the CPU 34 is the D / A converter 3
It is supplied as a reference signal to the non-inverting input terminal of the comparator 38 via 6. The output signal of the comparator 38 is fed back to the inverting input terminal via the feedback resistor 40 and is also supplied to the AGC circuit 28 as a gain setting signal. The output signal of the video processing circuit 26 is supplied to the inverting input terminal of the comparator 38 via the resistor 42. Further, the output signal of the comparator 38 is also supplied to the diaphragm drive circuit 44 as a diaphragm setting signal.

Next, the operation of this embodiment will be described. The comparator 38 compares the reference signal supplied from the D / A converter 36 with the output signal of the video processing circuit 26, drives the diaphragm 24 via the diaphragm driving circuit 44 in accordance with the difference, and outputs the light guide 16 to the light guide 16. Incident lamp
The amount of illumination light from 22 is changed. Thereby, the brightness of the subject is adjusted, and as a result, the brightness of the image signal output from the CCD 20 is adjusted. At the same time, the output of the comparator 38 is supplied to the AGC circuit 28, the gain of the output video signal of the video process circuit 26 is also changed, and the brightness of the screen of the color monitor 14 is changed. Thereby, the brightness of the image is adjusted.

The reference signal output from the D / A converter 36 is changed as follows. The key scan circuit 32 sequentially scans the brightness setting switches 30a and 30b to detect the pressed key switch. This detection signal is supplied to the CPU 34, and the CPU 34 operates as shown in the flowchart of FIG. First, in step S1, it is determined based on the detection signal whether or not there is a key switch that is turned on. When it is determined that there is a key switch that is turned on, it is determined in step S2 whether or not the switch is turned on is chattering. If it is determined that chattering has not occurred, then in step S3 it is determined whether this key input is a new key input. If it is determined that the key input is new, digital data corresponding to the key switch that is turned on is output to the D / A converter 36 as shown in step S4. Here, assuming that the CPU 34 is provided with a latch, when the brightness setting switch 30a is pressed, the latched digital data is increased by a predetermined amount and output. On the contrary, when the brightness setting switch 30b is pressed, the digital data latched is reduced by a predetermined amount and output. After step S4, it is determined in step S5 whether or not the process ends.
If not, step S1 is executed again. If a negative determination is made in steps S1, S2 and S3, step S5 is executed.

In this way, a reference signal that digitally changes is generated by turning on / off the key switches 30a and 30b, and the brightness of the image is adjusted based on the reference signal. Therefore, the durability and reliability of the endoscope image signal processing circuit can be improved. Further, since the key switches 30a and 30b are covered with the drip-proof cover, the drip-proof property of the endoscope image signal processing circuit is also improved. If the change width of the CPU output data is reduced,
The reference signal changes finely and the brightness can be finely adjusted.

The present invention is not limited to the above-described embodiments and can be modified in various ways. For example, in the above-described embodiment, as the brightness adjustment method, the aperture that changes the light amount of the illumination light is controlled, and the brightness of the monitor screen is controlled by changing the gain of the video signal, but either one may be used. .

[Effect of the Invention] As described above, according to the present invention, a reference signal that digitally changes according to the operation of the brightness setting switch is generated, and the brightness of the image is adjusted based on the reference signal. The durability and reliability of the image signal processing circuit for an endoscope are improved.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of an image signal processing circuit for an endoscope according to the present invention, and FIG. 2 is a flow chart for explaining the operation of this embodiment. 22 ... Lamp 24 ... Aperture 26 ... Image processing circuit 28 ... Automatic gain adjustment circuit 30a, 30b ... Brightness setting switch 32 ... Key scan circuit 34 ... CPU 36 ... D / A converter 38 ... Comparator 44 ... Aperture drive circuit

 ─────────────────────────────────────────────────── --- Continuation of front page (72) Inventor Masahiko Sasaki 2-43-2 Hatagaya, Shibuya-ku, Tokyo Inside Olympus Optical Co., Ltd. (56) Reference JP-A-60-83476 (JP, A) JP Sho 60-72383 (JP, A)

Claims (1)

[Claims] 1. An endoscope for adjusting the brightness of an image obtained by the image signal by changing the gain of an image signal picked up by the endoscope and the amount of illumination light for imaging the endoscope. In the image signal processing circuit, a switch that adjusts the brightness of the image and a brightness setting signal that detects the operation of the switch and digitally changes by a predetermined value every certain period when the switch is operating Means for adjusting the brightness of the image based on the brightness setting signal, and a protection device for watertightly protecting the surface of the switch so that the switch can be operated by pressing the outer surface. An image signal processing circuit for an endoscope, comprising: a drip member.