JP2006015131A - Electronic endoscope system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an endoscope system preventing deterioration of an image quality due to noise even if handling a high-resolution image and preventing possible deterioration of a display screen caused by A/D conversion or D/A conversion in an electronic endoscope system having a monitor electronic endoscope, a processor for the endoscope processing image signals outputted from the electronic endoscope, and a monitor displaying the image processed by the processor for the endoscope. <P>SOLUTION: The picture signals of the image outputted from the processor for the endoscope are transmitted from the processor to the monitor by a differential transmission. The differential transmission may be performed by transmitting digital signals, for example, the transmission based on DVI (Digital Visual Interface) standards. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention provides a monitor electronic endoscope, an endoscope processor that processes an image signal output from the electronic endoscope, and a monitor that displays an image processed by the endoscope processor. The present invention relates to an endoscope system.

2. Description of the Related Art Conventionally, for example, a diseased part is imaged by an imaging device provided at the distal end of an endoscope, such as that described in Patent Document 1, and an image signal output from the imaging device is processed by an image processing circuit to be monitored. There is known an electronic endoscope system for displaying on the screen.
Japanese Patent Laid-Open No. 11-267096

  FIG. 1 is a schematic diagram of an example of a conventional electronic endoscope system. The electronic endoscope system 100 includes an endoscope 101, a processor 102, and a liquid crystal monitor 103. The endoscope 101 includes an image pickup element 107 such as a CCD at its distal end. The processor 102 is connected to the endoscope 101 and processes an image signal output from the image sensor 107 to generate an analog video signal in a predetermined format. The processor 102 includes an analog / digital (hereinafter referred to as A / D) converter 109, a memory 111, an image processing circuit 113, a digital / analog (hereinafter referred to as D / A) converter 115, and an analog signal output unit 117. In this way, the image signal is processed to generate an analog video signal. The video signal generated by the processor 102 is sent to the monitor 103 via the analog signal cable 125, and an image is displayed on the monitor 103. Here, the processor has a display device controller 123, thereby performing processing necessary for displaying on the monitor 103. The processor 102 has a built-in light source 105, and illumination light generated by the light source 105 is sent to the distal end portion of the endoscope 101 via a light guide built in the endoscope 101. The periphery of the endoscope tip is irradiated with this illumination light.

  The image processing operation by the above-described conventional electronic endoscope system will be described below. The image of the observation object is picked up by the image pickup device 107, and the image pickup device 107 outputs an analog image signal corresponding to the picked-up image. This image signal is transmitted to the A / D converter 109 of the processor 102. The image signal which is an analog signal is converted into digital image data by the A / D converter 109 and stored in the memory 111. The digital image data stored in the memory 111 is read out to the image processing circuit 113. The image processing circuit 113 performs various image processing on the read digital data, and further converts it into a digital video signal. The video signal is converted again to an analog video signal by the D / A converter 115 and input from the analog signal output unit 117 to the analog signal input unit 119 of the monitor 103 via the analog signal cable 125. . The video signal converted into the analog signal is converted again into a digital signal by the A / D converter 121 and inputted to the display device controller 123. Based on this digital signal, the display device controller 123 controls each pixel of the liquid crystal screen of the monitor 103, and as a result, an image captured by the image sensor 107 is displayed on the liquid crystal screen of the monitor 103.

  However, the conventional endoscope system transmits the video signal using the analog signal cable 125 such as the PC monitor analog RGB cable in the conventional endoscope system described above for RGB. The cable 125 generally assigns one signal cable for each of the RGB colors and the synchronization signal.

  Due to the demand for higher image quality, the resolution of high-quality (high pixel) CCDs has improved to several million pixels. As a result, in recent endoscope systems, the resolution of images displayed on a monitor is also increasing. In order to suppress flickering of the screen, the frame display speed is preferably 60 frames / second or more. For this reason, as the display resolution on the monitor increases, the amount of data to be transmitted by the analog signal cable 125 increases. For example, when displaying an image of about several million pixels per frame at 60 frames / second, the number of pixels (dot clock) that must be transmitted per second is several hundred megahertz. Thus, when the amount of data that the cable must transmit increases, when noise is added to the cable from the outside, the amount of change in the luminance value of the pixel to which the noise is added is small (that is, the resolution is low). ) It becomes larger than the case. Therefore, an endoscope system using an image sensor with a large number of pixels tends to have a greater degree of image degradation due to noise. In particular, in an endoscope system, since a light source is likely to be a noise generation source, depending on the arrangement position of the monitor 103 and the processor 102, a lot of noise may be mixed, and the image quality of an image displayed on the monitor 103 may be greatly deteriorated. There is.

  In the endoscope system shown in FIG. 1, when attention is paid to analog / digital conversion of signals, the signal transmitted from the endoscope 101 to the processor 102 is an analog signal, and the A / D converter 109 outputs the analog signal. Is converted from a digital signal to an analog signal by a D / A converter 115, and further converted from an analog signal to a digital signal by an A / D converter 121. In general, A / D conversion and D / A conversion result in loss of signal data and deterioration in display image quality. Therefore, in order to improve the image quality of the video displayed on the monitor 103, it is desired to reduce the number of A / D conversions and D / A conversions as much as possible.

  The present invention has been made in view of the above circumstances. Its purpose is to prevent image quality deterioration due to noise even when handling high-resolution images, and to prevent display screen deterioration that may occur due to A / D conversion or D / A conversion. An endoscope system is provided.

  In order to solve the above problems, in the electronic endoscope system of the present invention, the video signal generated by the processor is transmitted by differential transmission from the processor to the monitor.

  In the differential transmission, one signal is transmitted with two cables having opposite phases to each other. On the signal receiving side (that is, the monitor side), the difference between the two received signals is taken to obtain information contained in the signal. These two cables are close to each other, and when noise is applied from the outside, the same level of noise is simultaneously input to the two cables. As described above, in the differential transmission, since the information to be transmitted is the difference between the signals sent by the two cables, the signal level of both cables is the same even if the same level of noise is added to both of the two cables. The noise is canceled by taking the difference. In the present invention, since the video signal is sent to the monitor by differential transmission, even if noise is applied to the cable, there is almost no loss of image information, and as a result, the image displayed on the monitor Deterioration is prevented.

  The transmission using the differential signal is particularly effective when the video signal is a digital signal. In digital signal transmission, it is necessary to lower the signal level as the data transmission speed increases, so that it is more susceptible to noise than analog signals. Therefore, when the data communication between the processor and the monitor is performed with a digital signal, it is possible to more effectively prevent the deterioration of the image quality of the image displayed on the monitor by using the differential transmission. Further, by converting a signal transmitted between the processor and the monitor into a digital signal, an image processed as digital image data in the processor is converted into a digital video signal without causing loss of information. Become. Therefore, the D / A converter required in the conventional configuration is not required, information loss due to the operation of the D / A converter can be prevented, and as a result, the image quality of the image displayed on the monitor is improved. . Furthermore, if the monitor can generate a screen control signal directly from a digital video signal, such as a liquid crystal monitor, the A / D converter required for the liquid crystal monitor in the conventional configuration becomes unnecessary. Information loss due to the operation of the A / D converter can be prevented, and as a result, the image quality displayed on the monitor is improved. In addition, since the number of parts constituting the processor and the monitor is reduced, there is a cost merit.

  As a video signal transmission method using differential transmission, for example, transmission based on the DVI standard is conceivable.

  As described above, according to the present invention, in an endoscope system that displays a high-resolution image output from a high-resolution image sensor on a monitor, deterioration of the image displayed on the monitor can be prevented. An endoscope system is realized. Further, since deterioration of image quality due to noise is prevented, the relative position of the monitor with respect to the processor can be made relatively free, and the monitor can be installed at a position easy for the operator to see.

  Embodiments of the present invention will be described with reference to the drawings. FIG. 2 is a schematic view showing an endoscope system according to the present invention. The electronic endoscope system 200 includes an endoscope 201, a processor 202, a monitor 203, and a signal cable 225 that transmits a digital signal between the processor 202 and the monitor 203. The signal cable 225 includes signal cables 225A and 225B.

  The endoscope 201 includes an imaging element 207 that images an observation target and outputs an image obtained as a result of imaging as an image signal. The processor 202 is an A / D converter 209 that generates digital image data by A / D converting an image signal from the image sensor 207 of the endoscope 201, and temporarily stores image data obtained as a result of the A / D conversion. A memory 211 that stores the image data, an image processing circuit 213 that converts the image data into a video signal 227 for display on the monitor 203, differential drivers 217R and 217G that output the video signal 227 as a differential signal to the outside of the processor 202, A signal output unit 217 provided with 217B and a light source 205 that emits irradiation light for irradiating the observation object via the endoscope 201 are provided.

  The video signal 227 processed by the signal output unit 217 is output to a video signal output terminal 229 provided on the outer shell of the processor 202. The output video signal 227 is output to the liquid crystal monitor 203 via the cable 225.

  The monitor 203 receives a video signal input terminal 228 to which the video signal 227 output from the processor 202 is input, and differential receivers 219R and 219G that process the video signal 227 as a differential signal obtained via the video signal input terminal 228. 219B, and a display controller 223 that performs data processing for displaying the video signal processed by the signal input unit 219 as an image on a monitor screen (not shown). With the above mechanism, an image captured by the image sensor 207 of the endoscope 201 is displayed on the liquid crystal screen of the monitor 203.

  In the present embodiment, the video signal 227 output from the processor 202 is a differential signal based on the DVI standard (Revision 1.0). Therefore, the video signal output terminal 229 is a DVI signal output terminal, and the video signal input terminal 228 is a DVI signal input terminal. In the figure, signals written in bold lines indicate digital signals. The features of the video signal 227 and its processing procedure will be outlined below.

  From the image sensor 207, luminance information corresponding to each pixel cell on the image sensor 207 is output at a predetermined timing. Each pixel cell of the image sensor 207 is provided with a color filter of a specific color, and the A / D converter 209 is adjacent to the image sensor 207 and sets a plurality of pixel cells having different color filters. It processes as one pixel and generates color information as RGB values from the luminance information of each of the plurality of pixel cells. The A / D converter 209 performs the same processing on all the pixel cells constituting all the image sensors 207, and generates digital image data corresponding to the image captured by the image sensor 207 from the obtained color information. This is stored in the memory 211. The luminance of each pixel in the digital image data is 8 bits for each of RGB (24 bits in total).

  The image processing circuit reads the digital image data stored in the memory 211 at a timing of every 1/60 seconds, and generates a digital video signal from this image data. Specifically, luminance information (8 bits) of each color of the case pixel and RGB is read out, information for control is added thereto, and a signal of 10 bits / pixel for each of RGB is generated. These signals 227R, 227G, and 227B are sent to the differential drivers 217R, 217G, and 217B, respectively. The synchronization signal is recorded in the control signal area of the R signal 227R.

  These signals 227R, 227G, and 227B are converted into differential signals by differential drivers 217R, 217G, and 217B, respectively.

  From the signal output unit 217 to the signal input unit 219, the video signal 227 is transmitted as a digital signal by differential transmission. Each type of video signal is provided with signal cables 225A and 225B, and the difference between the value of the signal transmitted by 225A and the value of the signal transmitted by 225B is the value of the video signal to be transmitted. . The video signals 227R, 227G, and 227B are each processed by the differential receivers 219R, 219G, and 219B constituting the signal input unit 219 before being processed by the signal output unit 217 (that is, not converted into differential signals). Reconverted to signal. The reconverted video signal 227 is transmitted to the display device controller 223. In this way, by using differential transmission for transmission of the video signal between the processor 202 and the monitor 203, even if noise is applied to the cable, there is almost no loss of image information, and the result is displayed on the monitor. Deterioration of the displayed image is prevented.

  In the embodiment described above, a digital signal is used as a video signal transmitted between the processor and the monitor. However, an analog video signal may be transmitted as a differential signal. Even in this configuration, it is possible to prevent deterioration of image quality due to noise added to the video signal. However, it can be said that the configuration of the present embodiment is more suitable in that A / D conversion and D / A conversion can be omitted.

FIG. 1 is a schematic view of a conventionally used electronic endoscope system. FIG. 2 is a schematic view showing an endoscope system according to the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 200 Electronic endoscope system 201 Endoscope 202 Processor 203 Monitor 205 Light source 207 Image pick-up element 209 A / D converter 211 Memory 213 Image processing circuit 217 Signal output part 219 Signal input part 223 Display device controller 225 Signal cable 227 Video signal 228 Video signal input terminal 229 Video signal output terminal

Claims (4)

An endoscope that captures an endoscopic image, which is an optical image of an observation object, with an imaging unit, and generates an image signal of the endoscopic image as an analog signal;
A processor that converts the image signal, which is an analog signal, into a video signal of a predetermined format;
A monitor that displays the endoscopic image based on the video signal;
The video signal is transmitted by differential transmission from the processor to the monitor.
An electronic endoscope system characterized by that.   The electronic endoscope system according to claim 1, wherein the video signal transmitted by the differential transmission is a digital signal.   The electronic endoscope system according to claim 2, wherein the differential transmission is based on a DVI standard.   The electronic endoscope system according to claim 3, wherein the processor includes a DVI output terminal.

Images