JPH02172436A - Picture forming system for electronic endoscope - Google Patents

Abstract

PURPOSE:To improve vertical resolution by a method wherein a signal one full field before and a signal two full fields before are read from a field memory, and the signal one full signal before is outputted 1/2H in delay. CONSTITUTION:When an R field signal is inputted as a real time signal to a field memory 16, a B field signal one full filed before is stored in a memory area 16B, and a G field signal two full fields before is stored in a memory area 16G. In which case, the R field signal is an odd number field, the B field signal is an even number field, and the G field signal is an odd number field. In this case, an R enable signal is outputted from a photo sensor 7 and is inputted to a switching means 21. When a switch 21B is changed over so as to pass through a delay circuit 20B and the signal is inputted to an encoder 19, only the B field signal is delayed 1/2H, and the R, G, and B field signals are united into an odd number field.

Description

Detailed Description of the Invention [Industrial Field 1] The present invention is directed to an imaging system for an electronic endoscope.
, B by sequentially driving the solid-state image sensor in a frame sequential manner. The present invention relates to an image forming system for an electronic endoscope that is capable of reading out B color image signals and displaying an observed image on a monitor screen as a frame image. [Prior Art] In an electronic endoscope, an insertion section connected to a main body operating section is inserted into a patient's body, etc., and an image of the observation target area is created by irradiating illumination light toward the observation target area. Although it is now possible to observe, the imaging system is
After photoelectric conversion is performed by a solid-state image sensor such as a COD and predetermined signal processing is performed by a processor, the image of the observation target portion is displayed on a 72T screen such as a cathode ray tube. This electronic endoscope has become widely popular in recent years because it allows multiple people to observe at the same time, image processing is possible, and has excellent recording performance and storage stability. In such electronic endoscopes, in order to reduce the diameter of the insertion section, a solid-state imaging device consisting of a single plate is used.
It is common to use a solid-state image pickup device that drives a solid-state image pickup device in a so-called field-sequential method, in which images of each color of blue and blue (B) are formed for each field, and the images are displayed by superimposing them. . In this way, in order to perform imaging using the field sequential method, the illumination light directed toward the observation target is separated into the three colors of R, G, and B by passing through a filter, and each color is divided into three colors. Illumination light using wavelength light must be time-divided and sequentially irradiated. For this purpose, an illumination optical system uses a rotating color filter having a filter area that transmits light in the wavelength range of each color of R, G, and B, and the rotating color filter is interposed in the optical path of the illumination light from the light source. is used. As an imaging system based on the above-mentioned frame-sequential drive, one having a configuration as shown in FIG. 1 has been known. In the figure, 1 is a light source that irradiates illumination light, and the light source l
The illumination light from the rotary color filter 2 passes through the R, G, and B wavelength ranges of light in sequence. This rotating color filter 2 is provided between a condenser lens 3 and a light guide 4, so that R, G, and B illumination lights are sequentially incident on the light guide 4. And this light guide 4
is guided to the tip of the insertion section of the endoscope, and by inserting this insertion section into a body cavity, etc., it is configured to be able to irradiate illumination light toward the inside of the body cavity, etc. . Here, as shown in FIG. 2, the rotating color filter 2 has an R filter area 2R and a G filter area 2G on its outer periphery.
, has three compartments of B filter castle 2B, and has a motor 5
By rotationally driving the R filter area 2R, the G filter area 2G, and the B filter area 2B sequentially to the optical path of the illumination light, illumination with each wavelength light of R2O and B is performed sequentially. In addition, each filter area 2R, 2G,
Each transition part of R2B is provided with an index 6, and by detecting the index 6 with a photosensor 7, an enable signal for identifying the start of the illumination light of R2O,B is formed. There is. Next, 10 indicates a COD as a solid-state image sensor, and the C
The CD 10 is provided at the tip of the insertion section, and an image of the observation target area is formed on this CCD 10 and photoelectrically converted. The image signal is read out by transferring the charges accumulated in this CCD 10, and in order to drive this CCD 10, a synchronizing signal generator 11 is provided. The synchronization signal generator 11 receives the R, G, and B enable signals from the photosensor 7 described above, and generates synchronization signals for controlling the readout of each color image signal based on the enable signals. The signal is input to the timing pulse generator 12. Then, based on the signal from the synchronization signal generator 11, the timing pulse generator 12 and the CCD drive circuit 13
A timing pulse for reading drive is input to the CCD 10, and the CCD 10 is driven based on this signal, and the R, G, B
The image signals of each color are sequentially read out. R, G read out from the CCD 10 as described above
, B color image signals are amplified by the process amplifier 14, converted to digital signals by the A/D converter 15, and stored in the R, G, and B memory areas 16R, 916G, and 16B.
are written in the field memory 16 having R, G,
Each color image signal of B is written. and,
Each time the writing of each color image signal is completed, an enable signal is input from the synchronizing signal generator 11 to the memory drive circuit 17, and a signal for reading the data written in the field memory 16 is sent from the memory drive circuit 17. The R, G, and B color image signals are input and read out simultaneously. These color image signals are then sent to the D/A converter 1.
The signals are D/A converted by 8R, 18G, and 18B, and a composite signal is formed by an encoder 19, so that an image of the observation target can be displayed on a monitor screen. (Problem to be Solved by the Invention 1) By the way, when reading out the R, G, and B color image signals from the CCD 10, the signals are read out while repeating field shifts. When the color image signals are sequentially read out, if the R color image signal is read out in an odd field, a field shift is performed when the primary G color image signal is read out, and the even field is read out. Then, the B color image signal becomes an odd field.Furthermore, the next normal color image signal is shifted to an even field, the G color image signal becomes an odd field, and the B color image signal becomes an even field. Sequential field shifts are repeated,
Each color image signal will be read out. Therefore, C, R, G written in field memory lδ,
Each B color image signal contains a mixture of even and odd fields, and if this is directly interlace scanned and output as a frame image, vertical jitter will occur and a clear image will not be obtained. It turns out. Therefore,
In conventional imaging systems, non-interlaced scanning is performed to output field images. Here, although the method of forming a field image as described above has a good horizontal resolution, it has a disadvantage that it is unable to form a clear image because the vertical resolution is poor. The present invention has been made in view of the above points, and when the color image signal in the - field is input to the field memory, the color image signal of the previous two fields already recorded in the field memory is By focusing on the fact that the color image signal before one field is from a different field, and the color image signal from two fields before is from the same field, by converting the color image signals from different fields into the same field, It is an object of the present invention to provide an image forming method for an electronic endoscope that is capable of forming frame images by interlaced scanning. [Means for Solving the Problems] In order to achieve the above-mentioned object, the present invention provides a method that, when a negative field signal among each field image signal recorded in the field memory is taken into the field memory, The signal one field before the field signal,
The device is characterized in that a signal of two fields before is read from the field memory, and among these field signals, a signal of one field before is delayed by (1/2)H and output. [Function] By configuring as described above, the - field image signal is input to the field memory, and this and the image signals for two fields already recorded in this field memory are simultaneously read out, and the D. /A conversion and input to the encoder, the image signal before the l field is (1
/2) Since the signal is delayed by H, the R, G, and B color image signals are converted into pseudo-framed signals so that the fields of the R, G, and B color image signals are even or odd. Therefore, it becomes possible to form a component signal based on this signal, perform interlaced scanning, and display it as a frame image on a monitor screen, resulting in good vertical resolution and a clear image. [Example] Hereinafter, an example of the present invention will be described in detail based on FIGS. 3 and 4. In this embodiment, the same or equivalent components as those of the prior art described above will be given the same reference numerals and the explanation thereof will be omitted. In this embodiment, after D/Δ converting the R, G, and B image signals output from the field memory 16, a delay circuit delays the signal lines S and one station H, which are respectively transmitted to the encoder 19 as they are. 20R, 20G, 20
The configuration is such that it can be switched between the delay line d and the delay line d via B. For this purpose, switches 21R and 21G are used, respectively.
, 21B is provided. The switching operation of the switching means 21 is configured to be performed based on enable signals R2O and B sent from the photosensor 7 via the synchronization signal generator 11. For example, as shown in FIG. 4(a), the CG
Field image signals are read out in the order of R, G, and B from D10 and are sequentially stored in each memory area 1 of field memory]6.
[iR, 16G, 16B] At this time, as shown in FIG. 2(b), the field memory 1
6, the memory area 16G contains the
A G field signal before the field is recorded, and a B field signal two fields before is recorded in the memory area 16B. Here, if the R field signal, which is the real-time signal described above, is an odd field, the B field signal before l field recorded and held in the memory area 16B is an even field, and
The G field signal recorded in G field two fields before is an odd field that is the same field as the R field signal. At this time, as shown in FIG. 4(C), an R enable signal is output from the photosensor 7, and this R enable signal is input to the switching means 21 via the synchronizing signal generator 11, so that the R When the enable signal is input, the switch 21B on the output side of the memory area 15B of the B field is switched via the delay circuit 20B, and the memory area 16R of the R field and G field is switched.
, 16G are input to the encoder 19 via a route that does not go through the delay circuits 20R and 20G. By this, B
Only the field signal is delayed by (1/2)H, as shown in the figure (
As shown in d), the R, G, and B field signals are converted into an odd field O', and the R, G, and B field signals, which are originally odd field 0, are unified into an odd field. Ru. Next, when the G field signal is taken into the field memory 16 as a real-time signal, this G field signal is an even field E, and the R field signal recorded in the field memory 16 one field before is this. are different odd fields 0. Therefore, by delaying this R field signal by HH by the switching means 21 based on the G enable signal, the R, G, and B field signals are unified into an even field as an even field E'. Can be done. Furthermore, when the B field signal is taken into the field memory 16 as a real-time signal, the first
Since the G field signal before the frame is an even field E of a different field, it is delayed by 34H to match the other field signals, and is made into an odd field O'. By repeating the above operations, it becomes possible to sequentially perform interlace scanning using R, G, and B pseudo-framed signals every 1760 seconds as shown in the figure, and as a result, as a frame image. It becomes possible to display an image of the observation target on a monitor screen, and it becomes possible to improve the vertical resolution, which is a drawback of field images. [Effects of the Invention] As explained above, according to the present invention, when a negative field signal or a real-time signal is taken into a field memory, a signal one field before this field signal and a signal two fields before this field signal are are read out from the field memory, and the signal from one field before each of these field signals is delayed by (1/2)H and outputted, so that each field of RlG and B output simultaneously from the field memory. It became possible to convert signals into the same field and display them on the monitor screen as frame images using interlaced scanning, increasing the vertical resolution and obtaining high-quality images. .

[Brief explanation of the drawing]

1 and 2 show the prior art, FIG. 1 is a block diagram showing the configuration of an imaging system, FIG. 2 is an explanatory diagram of the configuration of a rotating color filter, and FIGS. 3 and 4 are in accordance with the present invention. Fig. 3 is a block diagram showing the configuration of the imaging system, Fig. 4 shows the pseudo frame processing of the image signal, and Fig. 4(a) shows the output signal of the COD; Figure (b) shows the characteristics of the signal recorded in the field memory, Figure (c) shows the pulses of each R, G, and B enable signal, and Figure (d) shows the characteristics of the signal input to the encoder. It is an explanatory diagram. 1: Light source, 2 two-rotation color filter, 2R, 2G, 2
B: Filter area, 4 light guides, 6: Index, 7: Photo sensor, lO+ccD, 11: Synchronous low signal generator, 12: Timing pulse generator, 13: CCD drive circuit, 14: Process amplifier, 15: A/ D converter,
16: Field memory, 1 [iR, 16G, 16B
:Memory castle, 17:Memory drive circuit, 18R, 16G
, 26B: D/A converter, 20R, 20G, 2
0B: Delay circuit, 2 switching means, 21R, 2
1G, 21B: Switch. α's box■'s α's

Claims (2)

[Claims] (1) A single-plate solid-state image sensor is installed at the tip of the insertion section of the electronic endoscope, and time-divisional illumination is performed using light in each of the R, G, and B wavelength regions toward the observation target area. An electronic endoscope in which G and B color image signals are sequentially formed field by field and recorded in a field memory, and each R, G and B color image signal is simultaneously read out and displayed on a monitor screen. When one field signal among the field signals is taken into the field memory, a signal one field before this field signal and a signal two fields before this field signal are read out from the field memory, and each of these is read out from the field memory. An image forming system for an electronic endoscope, characterized in that a signal from one field before among field signals is output after being delayed by (1/2)H. (2) A (1/2)H delay line is provided on the output side of each of the R, G, and B memory areas of the field memory, and a switching means is used to select a route that passes through the (1/2)H delay line and a route that does not pass through the (1/2)H delay line. The image of the electronic endoscope according to claim 1, characterized in that the switching means is configured to switch between enable signals and enable signals of R, G, and B. Formation method.