JP3000712U - Brightness control device for endoscope - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a brightness control device for an endoscope, which can always control illumination to an appropriate brightness without being influenced by the size of an observation image displayed on a monitor screen. The purpose is to do. [Structure] An observation image transmitted from the tip of the insertion portion 3 by an optical image transmission means 2 is picked up by a television camera 10 attached to an eyepiece portion 5, and a video signal output from the television camera 10 is integrated circuit 26. In the brightness control device for an endoscope, which controls the brightness of the illumination device 20 for illuminating the observation range so that the average value of the video signal magnitudes obtained by the integration circuit 26 becomes constant. Circuit 26
Switch 27 for connecting and disconnecting the input line of the video signal to and the switch control for controlling the opening and closing of the switch 27 so as to prevent the video signal of the scanning line portion not including the observed image from being input to the integrating circuit 26. Means 30 and are provided.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 This invention is a brightness control of an endoscope in which a TV camera is attached to the eyepiece of the endoscope and the brightness of the endoscope image captured by the TV camera and displayed on the monitor is automatically controlled. Regarding the device.

[0002]

[Prior art]

 FIG. 9 shows a conventional device, in which a video signal output from the television camera 10 is branched and passed through a direct current reproduction circuit 72, and an image is displayed in a CR integration circuit 73 composed of a capacitor 73a and a resistor 73b. The average value of the signal magnitude (average brightness value) is obtained.

Then, the average value is compared with the reference voltage (Vref) by the comparator 74, and a control signal is output from the comparator 74 to the brightness control circuit 76 of the light source device 75 so as to be always equal to the reference voltage. It

Then, according to the control signal, the brightness of the light source lamp 77 or the operation of the light flux diaphragm 78 is controlled, and the brightness of the illumination light that enters the illumination optical fiber bundle 7 and illuminates the observation range is controlled. .

The incident end face of the image transmission optical fiber bundle 2 built in the endoscope 1 is arranged at the image forming position of the objective lens 4 at the front end of the insertion part 3, and the emission end face is arranged at the eyepiece part 5. It is arranged.

Then, the exit end face of the image transmitting optical fiber bundle 2 is projected by the eyepiece lens 6 or the like onto the solid-state image sensor 11 in the television camera 10 to be imaged, and a video signal including an observed image in the central portion is transmitted to the television camera. It is output from 10. Reference numeral 12 is a video signal processing circuit, and 13 is a monitor using a CRT or the like.

[0007]

[Problems to be solved by the device]

 When the television camera 10 is attached to the eyepiece 5 of the endoscope as described above, the observation image monitor is displayed in the center of the screen, and its size is different from that of the endoscope and the television camera 10. Depending on the type of adapter that connects to the eyepiece unit 5, etc., the parts other than the observation image become almost dark.

Therefore, even if the observed image has just the right brightness, that is, the brightness per unit area is very good, the average brightness of the entire screen varies depending on the size of the observed image. The smaller the size, the darker the average brightness of the entire screen.

On the other hand, the brightness of the illumination is controlled so that the average brightness of the entire screen becomes uniform as described above. Therefore, if the size of the observed image is small, the observed image may be white. On the contrary, if the observed image is large, it may be dark and difficult to see.

Therefore, the present invention provides a brightness control device for an endoscope, which can always control illumination to an appropriate brightness without being influenced by the size of an observation image displayed on a monitor screen. The purpose is to

[0011]

[Means for Solving the Problems]

 In order to achieve the above object, the endoscope brightness control device of the present invention captures an observation image transmitted from the distal end of the insertion portion by the optical image transmission means with a television camera attached to the eyepiece. , The video signal output from the television camera is input to the integrating circuit, and the brightness of the illumination device that illuminates the observation range is adjusted so that the average value of the video signal magnitudes obtained by the integrating circuit becomes constant. In the brightness control device of the endoscope to be controlled, the switch for interrupting the input line of the video signal to the integration circuit and the video signal of the scanning line portion not including the observation image are sent to the integration circuit. Switch control means for controlling opening and closing of the switch is provided so as to prevent input.

The average value of the video signal magnitudes obtained by the integration circuit may be corrected in accordance with the area of the observed image included in the video signal input to the product circuit. .

[0013]

【Example】

 Embodiments will be described with reference to the drawings. In FIG. 1, the entrance end face of the image transmission optical fiber bundle 2 built in the endoscope 1 is arranged at the imaging position of the objective lens 4 at the tip of the insertion part 3, and the exit end face is arranged in the eyepiece part 5. ing.

Then, the exit end face of the image transmitting optical fiber bundle 2 is projected by the eyepiece lens 6 or the like onto the solid-state image sensor 11 in the television camera 10 to be imaged. It is output from 10. Reference numeral 12 is a video signal processing circuit, and 13 is a monitor using a CRT or the like.

The illumination light emitted from the light source lamp 21 arranged in the light source device 20 is converged by the condenser lens 22 on the incident end face of the illumination optical fiber bundle 7 and transmitted through the illumination optical fiber bundle 7. Then, the observation area is illuminated by being emitted forward at the tip of the insertion portion 3.

A movable light beam diaphragm 23 is arranged between the light source lamp 21 and the condenser lens 22, and the opening of the diaphragm 23 or the brightness of the light source lamp 21 is controlled by a control signal from the brightness control circuit 24. Is controlled, and the illumination light flux (brightness) incident on the illumination optical fiber bundle 7 is adjusted.

The video signal output from the television camera 10 is branched and sent to the CR integrator circuit 26 including the capacitor 26a and the resistor 26b through the direct current reproduction circuit 25, where the average of the video signal magnitude is calculated. The value (average brightness) is calculated.

An openable and closable switch 27 for connecting and disconnecting the input line of the video signal to the integration circuit 26 is provided between the direct current reproduction circuit 25 and the integration circuit 26. It is controlled by the switch control circuit 30.

FIG. 2 shows a part of the switch control circuit 30 and the integrating circuit 26. The signal output from the DC regenerating circuit 25 is input to a comparator 31 provided in parallel with the switch 27 and compared with the reference voltage Vref, and the comparison result is a high level “H” or a low level “L”. Is output from the comparator 31.

The output signal from the comparator 31 is input to the clock input terminal C of the D flip-flop 32. The data input terminal D of the flip-flop 32 is connected to the high level power source, and the vertical input signal / R receives the vertical synchronizing signal (/ VSYNC).

Reference numeral 33 denotes a microcomputer including a central processing unit 33a, a timer 33b, etc., to which an output signal from the output terminal Q of the flip-flop 32 and a vertical synchronizing signal are input. Further, the output signal from the integrating circuit 26 is passed through the buffer 35, converted into a digital signal by the A / D converter 36, and input to the microcomputer 33.

The microcomputer 33 outputs a control signal for controlling the opening and closing of the switch 27 to the switch 27, and a control signal for controlling the brightness of the illumination is a brightness control circuit of the light source device 20. 24 is output.

FIG. 3 is a time chart showing the operation of the switch control circuit 30, and FIGS. 4 and 5 are flowcharts showing the software of the microcomputer 33. The operation of the embodiment will be described with reference to these as well. To do. S indicates a processing step.

Note that t ₁ is the time from the vertical synchronizing signal input to the Q output becoming “H” tp: the time from the vertical synchronizing signal input to the switch control signal being “H” tw: The switch control signal is “ H "time tc: time from input of vertical synchronizing signal to image center tv: vertical scanning time

The video signal of is input to the comparator 31, and when the voltage exceeds the reference voltage Vref, the output of the comparator 31 becomes “H”. Since the video signal also includes the horizontal synchronizing signal, the output from the comparator 31 returns "H" and "L" as if it were oscillating.

The output signal from the comparator 31 is subjected to edge detection by the D flip-flop 32 and input to the microcomputer 33. In the microcomputer 33, the switch control signal is set to "L", tp = ta (maximum expected value of tp), tm = 0, tw = (tc-tp) × 2 as an initial setting (S1). .

Then, the time t ₁ from the input of the vertical synchronizing signal until the Q output of the flip-flop 32 becomes “H” is measured (S 2 to S 5). Then, when the count of the timer 33b reaches tp, the switch control signal is set to "H" (S8) and output is performed only for the period of tw (S9 to S15). tw is obtained as _{t w = (tc-t 1} ) × 2. tc is the time from the input of the vertical synchronizing signal to the input of the observation image center, and the observation image is assumed to be located at the center of the screen.

The value of t ₁ at this time is stored in tp and is output from the microcomputer 33 even if the Q output input to the microcomputer 33 does not become “H” within the next vertical scanning period. As the switch control signal to be output, “H” of tw is output after the tp time has elapsed.

When the Q output becomes “H” within the period of tp, the elapsed time t ₁ from the vertical synchronizing signal at that time is written in tp, and the value of tw is also updated (S 6 to S 7). ). Therefore, the minimum value of t ₁ is always written in tp. The micro computer 33 sets the switch control signal to "H" after the tp time has elapsed (S8), and then sets it to the "L" after tw has elapsed (S9 to S15).

In this way, the switch 27 is controlled to be opened and closed, and when the video signal for the scanning unit including the observation image is sent, the switch 27 is closed, and the scanning line not including the observation image is included. The switch 27 is opened when the partial video signal is sent.

That is, as schematically shown in FIG. 6, the switch 27 is closed only when a video signal of a certain width (L1) portion of the observed image 51 is input to the screen 50, and the video signal is integrated. The video signal which is input to 26 and is averaged therein is input to the microcomputer 33 as digital data through the buffer 35 and the A / D converter 36 (S 16). Then, the microcomputer 33 compares this data with a predetermined value and outputs a light source control signal to the brightness control circuit 24 of the light source device 20 (S17).

In FIG. 7, after the processing step S16, a step (S17) of calculating a correction coefficient K and further correcting the light source control signal is added to make the brightness of the observed image more appropriate. This is an example in which they are brought closer to each other, and the other points are all the same as the above-mentioned examples.

As shown in FIG. 8, when the horizontal width of the screen 50 is L2, the area of the observed image 51 is Sa, and the rectangular area averaged in the above-described embodiment is Sb, the correction coefficient K is Sb. The conventionally required average value Av is represented by Av = Ia / Sa (Ia: integrated value of luminance in the observed image 51).

On the other hand, since the average value Av ′ obtained in the above-described embodiment is the average value for the rectangular area Sb, Av ′ = Ia / Sb.

Therefore, Av = (Sb / Sa) · Av ′, and by multiplying Av ′ by the correction coefficient K (K = Sb / Sa), the originally required average value can be obtained. In this embodiment, in which the observed image is a perfect circle, K = Sb / Sa = 4 · L2 / (π · L1).

The correction coefficient K calculated in S 17 in this way is multiplied by the light source control signal in S 18, and output to the brightness control circuit 24 of the light source device 20. It should be noted that the present invention is not limited to the above-mentioned embodiment, and may use a relay lens or the like as the optical image transmitting means, for example.

[0037]

[Effect of device]

 According to the present invention, the size of the video signal is averaged only in the portion where the observed image is present in the entire screen imaged by the television camera, and the brightness of the illumination is controlled based on that, so that the screen Regardless of the size of the observation image inside, appropriate illumination brightness control is performed, and a screen that is easy to see can always be obtained. Then, by further correcting the control signal according to the area of the observation screen, a more appropriate illumination brightness can be obtained.

[Brief description of drawings]

FIG. 1 is a schematic diagram of the overall configuration of a first embodiment.

FIG. 2 is a circuit diagram of the first embodiment.

FIG. 3 is a time chart showing the operation of the first embodiment.

FIG. 4 is a control processing flowchart of the first embodiment.

FIG. 5 is a flowchart of a control process according to the first embodiment.

FIG. 6 is an operation explanatory diagram of the first embodiment.

FIG. 7 is a control processing flowchart of the second embodiment.

FIG. 8 is an operation explanatory diagram of the second embodiment.

FIG. 9 is a schematic diagram showing the overall configuration of a conventional example.

[Explanation of symbols]

 1 Endoscope 2 Image Transmission Optical Fiber Bundle (Optical Image Transmission Means) 3 Insertion Part 5 Eyepiece 7 Optical Fiber Bundle for Illumination 10 Television Camera 20 Light Source Device 26 Integration Circuit 27 Switch 30 Switch Control Circuit

Claims (2)

[Scope of utility model registration request] 1. An observation image transmitted from the tip of the insertion portion by an optical image transmission means is imaged by a television camera attached to an eyepiece portion, and a video signal output from the television camera is input to an integrating circuit. In the brightness control device for an endoscope, which controls the brightness of an illuminating device for illuminating an observation range so that the average value of the magnitudes of video signals obtained by the integration circuit is constant, A switch for connecting and disconnecting the signal input line, and a switch control means for controlling the opening and closing of the switch so as to prevent the video signal of the scanning line portion not including the observed image from being input to the integrating circuit. A brightness control device for an endoscope, comprising: 2. The average value of the magnitudes of the video signals obtained by the integrating circuit is corrected in accordance with the area of the observed image contained in the video signals input to the integrating circuit.
Brightness control device for the endoscope described.