JP3057725B2 - Electronic endoscope device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an image pickup device mounted on an electronic endoscope or the like, in which a solid-state image pickup device is driven in a plane-sequential manner to obtain R (red), G
An image freeze device for acquiring image signals of each color (green) and B (blue) and superimposing the image signals of each color on a monitor screen or the like so that still images can be acquired. It is about.

[Related Art] Since an electronic endoscope is to be inserted into a narrow portion such as a body cavity or the like, the distal end of the insertion portion must be made as small as possible. Therefore, a solid-state imaging device such as a CCD as an imaging unit incorporated at the tip of the insertion portion needs to be small and compact, and for this purpose, a single solid-state imaging device is generally used. . Then, in order to improve the resolution of an image obtained by this single-plate solid-state imaging device, the solid-state imaging device is driven in a plane-sequential manner to acquire image signals of R, G, and B colors,
After simultaneous conversion by the field memory means, the video signals of these colors are superimposed and displayed as a color video on a display device.

Here, when observing the inside of the body or the like with an electronic endoscope, in addition to observing the image in a moving image state, it is often displayed on a display device as a still image, or a still image is photographed by a camera May be required. In particular, when an observation record is stored, it is often recorded in a still image state by a camera instead of a moving image state.

From such a demand, as an imaging system of the electronic endoscope, not only a normal moving image display method on the display,
It can also be displayed as a still image, that is, a frozen image.

[Problems to be Solved by the Invention] When a solid-state imaging device is driven by a plane sequential method, image signals of each color of R, G, and B are extracted in time series, and the entire R, G, and B signals are extracted. Since a time lag occurs between the color image signals until an image is formed, if one or both of the subject side and the imaging side move during shooting,
When the image signals of these colors are superimposed, alignment between the image signals cannot be achieved. However, when this image is displayed as a frozen image on a monitor as well as when displayed in a moving image state, there are drawbacks in that a color shift occurs and the resolution is reduced.

Therefore, in order to obtain a clear freeze image, the operator of the electronic endoscope operates the operation means such as the freeze shooting button repeatedly and repeatedly to select and record a clear image from the operation means. As a result, the operation of photographing a freeze image is extremely troublesome.

The present invention has been made in view of the above points, and its purpose is to detect the movement of a subject with a simple configuration, thereby automatically detecting the shooting timing of a freeze image, and An object of the present invention is to provide an image freezing device capable of obtaining a clear image.

[Means for Solving the Problems] In order to achieve the above-described object, the present invention provides a method for generating image data of each color of R, G, and B based on G image data.
Difference calculating means for calculating the difference between the level of the G image data and the data relating to the luminance signal generated from the R image data or the entire R, G, B image data; and a difference from the difference calculating means. Comparing means for comparing the signal with a reference value,
The apparatus has a motion detecting means for detecting the presence or absence of a motion of a subject, and is configured to set the operation timing of the switch means by the motion detecting means.

[Operation] As described above, when the solid-state imaging device is driven by the frame sequential method, the R, G, and B color images are sequentially acquired in a time-series manner in the imaging system, but are sequentially acquired in the display system. And color image data of three colors are simultaneously read from the memory, and a simultaneous color video signal is generated. For example, when the R image data is output from the solid-state imaging device, data relating to each of the G and B colors other than the R color image data is obtained earlier and read out already stored in the memory. Thus, a composite signal is generated from the three colors. In other words, the R image data, which is the real-time information currently transmitted from the solid-state imaging device, and the R image data are obtained one or two fields before and stored in the memory, and have a time difference from the R image data. The B and G image data having the three colors are read out from the memory, and these three color image data are combined by a color encoder and converted into a composite signal.

From the above, by comparing the real-time information with the memory information having a time difference from the real-time information, it is possible to detect the presence or absence of the movement of the subject. In addition, since the R, G, B color signals or the color difference signals for performing the motion detection can be easily obtained by a normal color endoscope system, it can be easily performed only by providing a difference calculation circuit and a comparison means. .

The endoscope is inserted into a body cavity such as a human body. The body cavity generally has a red color tone, and a single color of green hardly exists. For this reason, when comparing the R image data and the G image data and calculating the difference between the levels, the level of the R image data must be always higher. However, if the R image data and the G image data deviate from each other, the output level of the G image data becomes higher than that of the R image data at a transition point from a bright part to a dark part or a transition point from a dark part to a bright part. Output level. Therefore, by calculating R-G and extracting only the negative component, it is possible to determine whether or not the subject has moved. Then, when the above-mentioned negative component becomes equal to or less than a predetermined value when the freeze operation is performed, the switch means is operated to prohibit updating of data in the memory, thereby obtaining a freeze image without color shift. Can be.

Further, in a case where a luminance signal is formed from these signals in addition to the R, G, and B image data described above, the luminance signal and any image data, for example, G image data You can also compare.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

First, FIG. 1 shows the entire configuration of a photographing device for an electronic endoscope. In FIG. 1, reference numeral 1 denotes a light source lamp, and 2 denotes a light guide.
A rotary color filter 3 is interposed in the illumination light path to 2a. As is well known, the color filter 3 includes an R filter region that transmits R (red) wavelength region light, a G filter region that transmits G (green) wavelength region light, and a B (blue) wavelength region. A B filter area for transmitting light is provided, and by rotating the color filter 3, illumination is sequentially performed with wavelength lights of R, G, and B colors. The R, G, B sequential illumination light is transmitted by the light guide 2 and is emitted from the emission end 2b to the subject through the illumination lens 4.

Next, reference numeral 5 denotes a CCD, and an image of a subject which is sequentially illuminated by the above-described R, G, and B is formed on the image forming surface of the CCD 5 and photoelectrically converted. CC pulse
By applying the signal to D5, the image signals are sequentially read. The R, G, and B image signals are transmitted to the processor 7, and after the processor 7 performs predetermined signal processing, the subject image is displayed in color on the screen of the display device. .

Next, the processor 7 has first signal processing means 10 for processing an output signal from the CCD 5, and the first signal processing means
The output signal of 10 is converted into a digital signal by the A / D converter 11 and stored in the field memory 12. Here, the field memory 12 includes an R memory area 12R for storing R image data, a G memory area 12G for storing G image data, and a B memory area 12B for storing B image data. On the output side of each memory area 12R, 12G, 12B in the field memory 12, D / A converters 13R, 13G, 13B are provided, respectively, and these D / A converters 13R,
After being converted to analog signals in 13G and 13B, the second
After further signal processing is performed by the signal processing means 14, the composite video signal is generated by the color encoder 15 for the three color image data.

Further, in order to read and drive data in the field memory 12, a memory drive circuit
The memory drive circuit 16 detects when each of the R, G, and B filter areas in the color filter 3 enters the illumination light path and detects the R, G, and B enable signals. A synchronous signal generator 18 is connected together with the enable signal generator 17 to be generated. Therefore, data writing and reading control to the field memory 12 are controlled based on the signal from the enable signal generator 17 and the signal from the synchronization signal generator 18. The synchronization signal generated by the synchronization signal generator 18 is transmitted to the CCD drive circuit 6 via the timing pulse generator 19.

Here, in addition to displaying the image of the subject in a moving image state on the display device, the display mode can also be displayed as a frozen image in a stationary state by switching the display mode. For this purpose, a freeze operation means 8 is provided at an appropriate position such as a body operation section of the endoscope,
The freeze operation means 8 is connected to an analog switch 20 as a switch means. Therefore, when the freeze operation means 8 is operated, the analog switch 20
, The enable signal generator 17 is locked, the data rewrite command signal is not input to the field memory 12, and the output signal of the color encoder 15 becomes a still image. At the same time, the shutter control means 21
Is activated, and the shutter of the camera is activated.

By the way, when displaying as a frozen image, there is a time lag when the images of each color of R, G, B are formed on the CCD 5, so that the subject and the distal end of the insertion section of the endoscope with the CCD 5 mounted thereon. If there is a relative movement between them, a shift occurs between the color images. For this purpose, a motion detecting means 22 for detecting the motion of the subject is provided. The motion detecting means 22 includes a differential operation circuit 23 for detecting the difference between the output level of the R image data and the output level of the G image data, that is, R-G, in a stage preceding the color encoder 15; Circuit 23
And a comparison circuit 24 that compares the output signal from the controller with a predetermined set value. Here, in the comparison circuit 24, R-
When only the negative component of the level difference of G is detected, the output signal from the differential operation circuit 23 is compared with the reference value set in the comparison circuit 24, and when the output signal falls below this reference value. Generate an output signal, activate the analog switch 20,
Disconnect the freeze button and prohibit the freeze.
When the absolute value of the negative component of the differential operation circuit 23 is smaller than the absolute value of the reference value, the output of the comparison circuit 24 becomes 0, and the analog switch 20 remains connected to the freeze button.
The rewriting of the field memory 12 is prohibited to freeze, and then the shutter control means 21 is operated to operate to turn on the shutter of the camera.

This embodiment is configured as described above, and its operation will be described next.

When observing and diagnosing the inside of the body using an electronic endoscope, the insertion portion is inserted into the stomach, duodenum, or the like via the oral cavity or the like. At this time, the light source lamp 1 is turned on, but the color filter 3 is rotating. As a result, the inside of the body cavity is photographed, and this photographing is normally displayed on the display screen in a moving image state.

By the way, when the affected part or the like is to be inspected more precisely, or when it is stored as a record, the freeze operation means 8 is operated to display a frozen image on the display screen as a frozen image. However, when the freeze operation button is operated, if there is a relative movement between the imaging unit CCD5 and the subject, R, G, B
In some cases, color misregistration occurs between the images of the respective colors, so that the resolution is poor and accurate observation cannot be performed.

Therefore, as described above, when the freeze operation means 8 is operated, the R image data and the G image data are fetched from the preceding stage of the color encoder 15 into the differential operation circuit 23, and the differential operation of the level in both image data is performed. Is performed.

Here, in the body cavity, since the entire subject has a reddish color tone, if there is no shift between the two image data, the calculated value of R-G does not become negative. . Now, as shown in FIG. 2 (a), it is assumed that there is a dark part D in the body cavity, and that the other part is bright. Comparing the line L in the figure, if there is no shift between the two image data, RG
Is always positive or 0, as shown in FIG. However, it is assumed that the dark portion of the G image data is shifted in the direction of the arrow with respect to the R image data as indicated by D 'in FIG. In this case,
As shown in FIG. 3C, the width d in the G image data
In the part, the output of the R image data is exceeded.

That is, the output level of the G image data exceeds the output level of the R image data when there is a shift between the two image data, and the output level difference increases as the shift amount increases. Therefore, each of the R and G signals is formed into an R-G signal by the differential operation circuit 23, is compared with a predetermined reference value by the comparison circuit 24, and only the negative component is extracted and integrated. This integrated signal is amplified and the analog switch 20
To prevent freeze.

This comparison is based on the R image data and the G image data
The comparison is performed every time output from the CCD5, and the comparison value is, for example, RG
When the absolute value of the negative component is smaller than the set value, that is, when it is determined that there is no motion, the output of the comparison circuit 24 is 0, and when the freeze switch is turned on while the analog switch 20 is connected to the freeze operation means, Enable signal generator 17
A command to prohibit the output of the enable signal is sent to the camera, and the contents of the field memory 12 are not updated so that the still image is obtained. I'm sick.

As described above, when the freeze operation button is operated, first, the presence / absence of the movement of the subject is detected by the movement detecting means 22. Since the freeze is performed, a clear freeze-free image without color shift can be reliably obtained by a single operation when capturing a freeze image. In addition, the intended purpose can be achieved by a simple circuit configuration whose basic configuration is simply provided with the differential operation circuit 23, the comparator 24 and the analog switch 20, so that the configuration of the processor 7 is particularly complicated. There is nothing.

Next, FIG. 3 shows a second embodiment of the present invention. In this embodiment, the luminance signal Y is generated from each of the R, G, B image data by the color encoder 15 '. Are shown.

In such a configuration, the differential operation circuit 23 'may also be configured to calculate the output level difference (Y-G) between the luminance signal Y and the G image data.
Motion detecting means 22 'can be formed. That is, the luminance signal Y is luminance information of the entire R, G, and B. When the subject is inside the body cavity, the G image data contributes almost only as a luminance component, and further includes the R image data. Since the level is always lower than the overall luminance Y, R, G,
Only when there is a deviation between the respective image data of B, Y-G takes a negative value. Therefore, the motion of the subject can be detected by calculating Y-G in this manner.

Structures other than these are the same as those in the first embodiment described above, and therefore, the same or equivalent members are denoted by the same reference characters and description thereof will be omitted.

[Effects of the Invention] The present invention uses G image data as a reference signal for comparison, calculates the difference between the level of the G image data and the R image data or data relating to the luminance signal, and calculates the difference between the level and the difference. Since the motion of the subject is detected by comparing with a predetermined reference value, the circuit configuration for performing the motion detection can be significantly simplified, and the motion of the subject can be detected very accurately and reliably. With little movement,
There is an effect that an extremely clear frozen image is obtained without color shift or the like.

[Brief description of the drawings]

FIGS. 1 and 2 show a first embodiment of the present invention.
FIG. 2 is an explanatory diagram showing the overall configuration of the image device of the electronic endoscope, FIG. 2A is an explanatory diagram of an image acquired by the image device,
FIG. 3B is an explanatory diagram showing the result of the RG calculation when there is no shift in the image. FIG. 3C is an explanatory diagram showing the result of the RG calculation when the image has a shift. FIG. 5 is an explanatory diagram showing the overall configuration of an image device of an electronic endoscope according to a second embodiment of the present invention. 3: color filter, 5: CCD, 7: processor, 8: freeze operation means, 12: field memory, 15, 15 ': color encoder, 17: enable signal generator, 20: analog switch, 21: shutter control means, 22,22 ': Motion detection means, 2
3, 23 ': differential operation circuit, 24: comparison circuit.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) H04N 7/18 A61B 1/04 372 G02B 23/24 H04N 9/04

Claims (3)

(57) [Claims] 1. A solid-state imaging device is provided at the tip of an insertion section in an electronic endoscope, and while the subject is sequentially illuminated with R, G, and B, image data of each of the colors of the subject by the solid-state imaging device. Are obtained and stored in a memory, these three color image data are simultaneously read, a color image is displayed on a display, and a freeze image can be displayed on the display by a switch means. Based on the G image data of the image data of each color B, the G image data and the R image data or R,
A difference calculating means for calculating a difference between the level and the luminance signal data generated from the entire image data of G and B; and a comparing means for comparing the difference signal from the difference calculating means with a reference value. An electronic endoscope apparatus comprising: motion detection means for detecting the presence or absence of motion of a subject; and setting the operation timing of the switch means by the motion detection means. 2. The method according to claim 1, wherein the difference calculation means sets a signal level of the R image data to R, and sets a signal level of the G image data to G.
And calculating R-G when the negative component is less than or equal to the reference value as the calculation result. Electronic endoscope device. 3. The difference calculation means calculates Y-G when the signal level of the data relating to the luminance signal is Y and the signal level of the G image data is G.
2. The electronic endoscope apparatus according to claim 1, wherein as a result of the calculation, when a negative component is equal to or less than the reference value, it is determined that the subject does not move.