JP2002185873A - Video signal output device - Google Patents

Abstract

(57) Abstract: A transmission cable used for exchanging signals between a CMOS image sensor and an external device is reduced. A CMOS image sensor has an image forming area in which a pixel signal corresponding to an image formed on a light receiving surface is generated, and a control signal storage area arranged outside the image forming area. Pixel signals are generated in the image forming area 22 by an imaging operation. The control signal storage area 23 stores a control signal for performing white balance adjustment or the like on the pixel signal. The pixel signal is processed in the pixel signal processing circuit 26 in accordance with the control signal, and is transmitted as a video signal to the microcomputer of the electronic endoscope via the transmission cable. The control signal is transmitted from the microcomputer to the CMOS image sensor 11 via the transmission cable.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a CMOS image sensor provided in, for example, an electronic endoscope and functioning as an imaging device.

[0002]

2. Description of the Related Art Conventionally, a CMOS image sensor and a CCD are known as image pickup devices provided in an electronic endoscope. Unlike a CCD, a CMOS image sensor can be made into a system one chip. Therefore, a pixel signal obtained by the imaging operation can be processed in the CMOS image sensor system, and can be output as a video signal in a format suitable for a monitor device or the like.

[0005] Processing performed in a CMOS image sensor system includes white balance adjustment, gain control, gamma correction, format conversion to a video system, and the like. These processing contents are performed by devices connected to the CMOS image sensor. It depends on the type or usage environment of the CMOS image sensor. Therefore,
In order to execute processing in a CMOS image sensor,
It is necessary to transmit a control signal corresponding to the processing content from the outside to the CMOS image sensor.

[0004]

That is, in an electronic endoscope using a CMOS image sensor, in addition to a power cable and a transmission cable for outputting a video signal to a monitor device, etc.,
A transmission cable for transmitting a control signal to the CMOS image sensor is required. Therefore, there is a limit in reducing the diameter of the flexible tube of the endoscope.

An object of the present invention is to reduce the number of transmission cables used for transmitting and receiving signals between a CMOS image sensor and an external device.

[0006]

According to the present invention, there is provided a video signal output apparatus comprising: a plurality of CMOSs arranged in a lattice; an image forming area in which pixel signals corresponding to an image formed are generated; CMOS arranged outside the image forming area
Sensor having a control signal storage area capable of storing a control signal for processing a pixel signal, and a pixel signal processing for performing a process according to the control signal on the pixel signal to obtain a video signal Means, and a transmission cable provided for inputting a control signal from the outside and outputting a video signal to the outside.

[0007] The CMOS image sensor is provided, for example, as an image pickup device of an electronic endoscope. According to this, the diameter of the flexible tube of the electronic endoscope can be reduced.

The control signal storage area is provided adjacent to the image forming area, and is preferably constituted by a row of CMOS parallel to one row of CMOS included in the image forming area. According to this, the control of reading the control signal from the control signal storage area is simplified.

A pixel signal generated in one column of CMOS in the image forming area and one column of CMOS in control signal storage means
Can be output to the outside every one horizontal scanning period. In this case, it is preferable that the control signal is input from the outside and stored in the control signal storage area during the horizontal scanning period in which the control signal can be output to the outside. In this case, after the video signal is output to the outside, the control signal is input from the outside.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 schematically shows the configuration of the electronic endoscope. The electronic endoscope (electronic scope) includes a flexible tube 10 inserted into a living body, and an operation unit 50 to which the flexible tube 10 is connected. At the tip of the flexible tube 10, a CMOS image sensor 11, which is an imaging device, is provided.

The flexible tube 10 is an elongated and flexible tube. In the flexible tube 10, a light guide 12 for guiding light for illuminating the inside of a living body and a channel 13 such as an air supply / water supply channel or a suction / forceps channel are provided.

On the light receiving surface of the CMOS image sensor 11, a large number of CMOSs are arranged in a lattice, and an image of a subject such as the inside of a living body is formed. Each CMOS generates a pixel signal (voltage signal) constituting an image, and the pixel signal is subjected to various processes such as noise removal and AD conversion, and is transferred to the operation unit 50 as a video signal. The pixel signal detection operation and various processing operations in the CMOS image sensor 11 are performed based on a clock signal generated by the clock generation circuit 14.

The operation unit 50 is provided with a microcomputer (CPU) 51 for controlling the imaging operation of the CMOS image sensor 11, the processing of processing pixel signals, and the like. The CMOS image sensor 11 and the microcomputer 51 are connected by a single transmission cable 15. The operation unit 50 is provided with a monitor device 52. The monitor device 52 includes a CMOS image sensor 11
Transmits a video signal via the transmission cable 15 to display an image. This image is a real-time moving image when a shutter button (not shown) provided on the operation unit 50 is not pressed, but is a still image when the shutter button is pressed.

The operation unit 50 is provided with a light source 53. Light emitted from the light source 53 is emitted from the distal end of the flexible tube 10 via the light guide 12. Operation unit 5
0 is provided with a power supply (not shown), and the power generated by the power supply is supplied to the CMOS image sensor 11 via the power cable 16. The power cable 16
Inside, a lead wire for grounding the CMOS image sensor 11 is also provided.

FIG. 2 shows the relationship between each CMOS in the CMOS image sensor 11 and the horizontal scanning lines displayed on the monitor device 52. CMOS image sensor 11
Is configured by arranging a plurality of CMOSs 21 in a lattice pattern. In the figure, the rectangular part surrounded by the solid line is the CM
An image forming area 22 in which a pixel signal corresponding to an image formed on the light receiving surface of the OS image sensor 11 is generated. A rectangular portion formed by the CMOS 21 arranged outside the image forming area 22 and surrounded by a broken line is a control signal storage area 23 for storing a control signal for processing a pixel signal.

The CMOS 21 has a width of 5
Although six are provided in the vertical direction, several hundreds are provided in the horizontal and vertical directions, respectively. A pixel signal is generated in each CMOS of the image forming area 22 by an imaging operation. In the image forming area 22, the top row (Line 1) of the CMOS rows arranged in the horizontal direction is one on the screen 54 of the monitor device.
Video signal L composed of pixels displayed at the top and arranged in the horizontal direction
Corresponds to 1. Similarly, the second, third, and fourth columns (Line 2,
Line 3 and Line 4) are 2 on the screen 54 of the monitor device.
They correspond to the video signals L2, L3, L4 in the third and fourth columns, respectively. On the other hand, in the control signal storage area 23, the CMOSs in the row (Line 5) closest to the image forming area 22 and the CMOS below the row (Line 6) correspond to portions not displayed on the screen 54 of the monitor device. The control signals are stored in these CMOSs as described above.

An X address designating circuit 24 and a Y address designating circuit 25 for specifying positions in the horizontal direction (X direction) and the vertical direction (Y direction) are connected to each CMOS 21. An arbitrary CMOS can be designated by the addressing circuits 24 and 25. For example, a predetermined voltage signal is supplied to the CMOS or the CMOS
A voltage signal can be read from the OS.

The pixel signal processing circuit 26 includes a noise removing circuit, an AD converter, and a function register, and is connected to a programmable function register 27. The programmable function register 27 is connected to the microcomputer 51 of the operation unit 50 via the transmission cable 15 (see FIG. 1), and stores a control signal such as a white balance adjustment coefficient transmitted from the microcomputer 51. .

In the pixel signal processing circuit 26, the CMOS 21 (Line) designated by the address designating circuits 24 and 25
Pixel signals, which are voltage signals, are input from 1 to Line 4), and noise is removed by a noise removing circuit. afterwards,
The pixel signal is converted into a digital signal by an AD converter, subjected to white balance adjustment, gain adjustment, and gamma correction by a function register, and is converted into a video signal in the form of, for example, a composite video signal. This video signal is transmitted to the microcomputer 51 via the transmission cable 15.

Referring to FIGS. 3 to 5, the operation of transmitting a video signal from CMOS image sensor 11 to microcomputer 51 and monitor device 52 and the operation of transmitting a control signal from microcomputer 51 to CMOS image sensor 11 will be described. explain. 3 and 4, the pixel signal processing circuit 26 and the programmable function register 27 are omitted.

During the transmission period, the CMOS image sensor 11
This is a period during which only the operation of transmitting the video signal from the side to the microcomputer 51 and the monitor device 52 is performed. C
In the MOS image sensor 11, the clock generation circuit 14
The pixel signal is read in accordance with the clock signal output from the, and is subjected to predetermined processing in the pixel signal processing circuit 26 (FIG. 2) to be converted into a video signal. As shown in FIG. 5, the video signals L1, L2,... Are partitioned by two horizontal synchronization signals H.

The horizontal synchronizing signal H and the vertical synchronizing signal (not shown) are separated by a synchronizing separation circuit 55 into video signals L1, L2,
... The horizontal synchronization signal H and the vertical synchronization signal are counted by a horizontal synchronization signal / vertical synchronization signal counter 56. In the microcomputer 51, the number of the horizontal synchronization signal H is checked to specify the video signal number, and by detecting the vertical synchronization signal, all the image signals for one screen from the CMOS image sensor 11 are detected. It is recognized that the signal has been output.

In the delay circuit 57, one column of video signals (L1, L1) transmitted with a certain time delay from the horizontal synchronizing signal H
2, L3 or L4) are extracted and held in the sample and hold circuit 58. The video signal is transmitted to the monitor device 52 until the video signal of the next column is transmitted.
Transferred to That is, the video signal is output to the monitor device 52 every one horizontal scanning period. Note that when the counter 56 determines that the signals L5 and L6 have been transmitted, they are control signals, and therefore need not be transferred to the monitor device 52, and are cut off by the mask circuit 59.

As described above, in the transmission period, only the transmission operation is performed in the CMOS image sensor 11, and the operation unit 5
At 0, only the receiving operation is performed.

During the transmission / reception period, the CMOS image sensor 1
The video signals L1 to L4 are transmitted from the microcomputer 5
1 and the monitor device 52, and control signals L5 and L6 from the microcomputer 51 to the programmable function register 27 (FIG. 2). In the CMOS image sensor 11, pixel signals are read out in the same manner as in the transmission period, and the pixel signals are subjected to predetermined processing in the pixel signal processing circuit 26 and converted into video signals.

The horizontal synchronizing signal H and the vertical synchronizing signal are separated from the video signals L1, L2,. The video signals L1 to L4 are, as described above,
The data is transferred to the monitor device 52 via the delay circuit 57 (FIG. 3) and the sample hold circuit 58 (FIG. 3). On the other hand, at the timing of the signals L5 and L6, the control signal generated by the microcomputer 51 is added to the horizontal synchronizing signal H by the adder 60, transmitted to the CMOS image sensor 11, and transmitted to the programmable function register 27 ( 2). The control signals L5 and L6 are supplied to the monitor 5 by the operation of the mask circuit 59.
2 is not transferred.

The control signals L5 and L6 are read from the programmable function register 27 and read from the CMOS.
It is stored in the control signal storage area 23 of the image sensor 11 and is used for processing such as white balance adjustment for the pixel signal generated in the image forming area 22 at that time.

As described above, in this embodiment, the control signal for performing processing such as white balance adjustment on the pixel signal read from the CMOS image sensor 11 is as follows.
The video signal is transmitted from the CMOS image sensor 11 to the CMOS image sensor 11 using a transmission cable 15 for outputting the video signal to the outside. That is, a transmission cable for outputting a video signal to a monitor device or the like, and a control signal
Since the transmission cable for transmitting the signal to the OS image sensor is also used, the diameter of the flexible tube of the electronic endoscope can be reduced.

[0029]

As described above, according to the present invention, the CMOS
The number of transmission cables used for transmission and reception of signals between the image sensor and the external device can be reduced. When the present invention is applied to an electronic endoscope, the diameter of a flexible tube can be reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram schematically showing a configuration of an electronic endoscope to which an embodiment of the present invention has been applied.

FIG. 2 shows each CMOS in a CMOS image sensor.
FIG. 3 is a diagram showing a relationship between the horizontal scanning lines displayed on the monitor device.

FIG. 3 is a block diagram illustrating an operation during a transmission period in which a video signal is transmitted from the CMOS image sensor to the microcomputer.

FIG. 4 is a block diagram showing an operation during a transmission / reception period in which a video signal is transmitted from the CMOS image sensor to the microcomputer and a control signal is transmitted from the microcomputer to the CMOS image sensor.

FIG. 5 is a diagram showing a video signal and a control signal in a transmission period and a transmission / reception period.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 CMOS image sensor 21 CMOS 22 Image formation area 23 Control signal storage area L1-L4 Video signal L5, L6 Control signal

Claims (6)

[Claims] 1. An image forming area in which a plurality of CMOSs are arranged in a lattice pattern, a pixel signal corresponding to an image formed is generated, and a CMOS arranged outside the image forming area. An image sensor having a control signal storage area capable of storing a control signal for processing the search signal, and a pixel signal for obtaining a video signal by performing a process according to the control signal on the pixel signal A video signal output device comprising: a processing unit; and a transmission cable provided to input the control signal from outside and output the video signal to outside. 2. The video signal output device according to claim 1, wherein the image sensor is provided in an electronic endoscope. 3. The control signal storage area is provided adjacent to the image forming area, and is included in the image forming area.
The video signal output device according to claim 1, wherein the video signal output device is configured by a CMOS column parallel to the CMOS column. 4. A pixel signal generated in one column of CMOS in the image forming area and a control signal stored in one column of CMOS of the control signal storage means are externally provided every one horizontal scanning period. The video signal output device according to claim 3, wherein output is possible. 5. The image according to claim 4, wherein the control signal is externally input and can be stored in the control signal storage area during a horizontal scanning period during which the control signal can be externally output. Signal output device. 6. The video signal output device according to claim 4, wherein after the video signal is output to the outside, the control signal is input from the outside.