JP3886757B2 - Electronic endoscope device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to image processing of an electronic endoscope apparatus, in particular, an electronic endoscope capable of displaying in detail the capillaries and the like in a body to be observed.
[0002]
[Prior art]
The electronic endoscope apparatus captures an object to be observed captured through an objective optical system by irradiating illumination light with an imaging element such as a CCD (Charge Coupled Device), and uses the object image as a monitor. In recent years, in this type of electronic endoscope apparatus, a zooming mechanism is incorporated in the objective optical system, and an object image is optically enlarged and displayed. Therefore, the details of the site of interest can be satisfactorily observed by the enlarged image displayed on the monitor or the like.
[0003]
[Problems to be solved by the invention]
By the way, in an electronic endoscope apparatus, an imaging target is often in a living body such as a digestive organ, and as shown in FIG. 5, in an enlarged object image 1 (display on a monitor or the like), a mucous membrane 2 A blood vessel (capillary blood vessel) 3 exists in the blood vessel, and the running state of the blood vessel 3 and the concentration state of the blood vessel (blood) 3 are important observation targets in diagnosis of a lesion, identification of a cancer tissue, and the like. On the other hand, since the living body is configured in pink or reddish color, the distinction between the blood vessel 3 and other tissues such as the mucous membrane 2 tends to be unclear. Therefore, if the blood vessel 3 can be clearly displayed in contrast with the mucous membrane 2, information useful for in-vivo observation and diagnosis can be provided.
[0004]
The present invention has been made in view of the above problems, and an object of the present invention is to provide an electronic endoscope apparatus capable of clearly displaying a blood vessel with high contrast on other tissues such as mucous membranes. It is in.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, an electronic endoscope apparatus according to a first aspect of the present invention includes a color signal forming circuit that forms a predetermined color signal based on a signal obtained by an image sensor, and the color signal forming circuit. A differential circuit that generates a differential signal by differentiating a predetermined color signal other than red color obtained in the above, a gain circuit that amplifies the differential signal output from the differential circuit, and a differential signal output from the gain circuit And a blood vessel enhancement circuit for amplifying at least a red signal other than the predetermined color signal to enhance the blood vessel.
According to a second aspect of the present invention, the color signal forming circuit forms red, green, and blue color signals, the differentiation circuit performs differentiation processing on the green signal, and the blood vessel enhancement circuit performs red and blue color processing. Is amplified by a differential signal.
[0006]
According to the above configuration, R (red), G (green), and B (blue) color signals are formed by the color signal forming circuit. For example, the G signal (or B signal) is differentiated by the differentiation circuit. The In this G signal, blood vessels are present in the low-level signal part (black part), and mucous membranes are present in the other parts, and the place where the level changes abruptly in this low-level part is detected by differential processing. To extract the position (presence) of the blood vessel. That is, the present invention detects the position of the blood vessel by differentiating the image signal other than red, which is the main color of the blood vessel.
[0007]
Next, the differential signal obtained by the differential circuit is amplified at a predetermined amplification factor and then supplied to the blood vessel enhancement circuit. Here, the differential signal is used as a gain signal and the R, B signals (or An R object signal is amplified by this R, B signal and a G signal that does not give a differential signal. That is, an image is formed by the R and B signals amplified according to the rapid change level of the differential signal and the G signal immediately before the differential circuit. As a result, the blood vessels in the mucous membrane have a high contrast. Is displayed.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows a partial configuration of an electronic endoscope apparatus according to the embodiment. This electronic endoscope apparatus is, for example, a simultaneous type, and includes a scope, a processor device, a light source device, a monitor, and a recording device. Etc. In FIG. 1, a CCD 10 as an image pickup device is provided at the distal end of the scope, and this CCD 10 passes through color filters [for example, Mg (magenta), G (green), Cy (cyan), Ye (yellow)] in units of pixels. The object image is captured. That is, the object to be observed is imaged by the CCD 10 by irradiating the object to be observed from the distal end of the scope through the light guide with the light guide. Further, if an objective optical system in which a variable power lens is movably incorporated is provided in front of the CCD 10, an enlarged image of the object to be observed can be obtained by driving the variable power lens.
[0009]
A CDS (Correlated Double Sampling) / AGC (Automatic Gain Control) 12 is arranged at the subsequent stage of the CCD 10. The CDS / AGC 12 is correlated with the output signal of the CCD 10. Double sampling is performed and predetermined amplification processing is performed. The CDS / AGC 12 is provided with a DSP (Digital Signal Processor) 16 via an A / D (analog / digital) converter 14.
[0010]
The DSP 16 performs various processes such as white balance and gamma correction, and forms a Y (luminance) signal and R (red) -Y and B (blue) -Y color difference (C) signals. A color conversion circuit 18 for converting the Y signal and the C signal into R (red), G (green), and B (blue) signals is provided at the subsequent stage of the DSP 16. That is, in this example, the DSP 16 forms the Y signal and the RY and BY C signals from the signals obtained through the Mg, G, Cy, and Ye color filters by color conversion calculation. The Y, C signals are further subjected to a color conversion operation to obtain R, G, B color signals. In addition, RGB signals can be directly formed in the DSP 16 instead of color difference signals.
[0011]
The differentiation circuit 20 that differentiates the G signal input from the color conversion circuit 18, the gain circuit 22 that amplifies the differentiation signal output from the differentiation circuit 20, and the conversion by the differential signal obtained by the gain circuit 22. A blood vessel emphasizing circuit 24 for amplifying the R and B signals output from the circuit 18 is provided, and processing for extracting blood vessels is performed by these circuits.
[0012]
That is, FIG. 2A shows an image 5G based on the G signal input to the differentiation circuit 20, and in this G image, the blood vessel 3 indicated by the dotted line is at a low level (a level close to black). Here, as shown in FIG. 2B, the signal level of the horizontal line La of the G image 5 is a signal in which the portion of the blood vessel 3 rapidly decreases. The differentiation circuit 20 differentiates this signal. As shown in FIG. 2 (C), a differential signal is formed that exhibits a sudden change in which a decrease → an increase in the double of this decrease → a decrease to the original level.
[0013]
The gain circuit 22 amplifies the differential signal output from the differentiation circuit 20 with a predetermined amplification factor g to obtain a signal having a large level difference, and the blood vessel enhancement circuit 24 uses the differential signal as a gain signal as an R signal. , B signals are amplified to form R signals [FIG. 3 (A)] and B signals [FIG. 3 (B)] having a level difference for emphasizing blood vessels as shown in FIG.
[0014]
Further, an R and B signal for blood vessel enhancement are input to the subsequent stage of the blood vessel enhancement circuit 24 and a G signal output from the color conversion circuit 18 is input, and an enhancer that enhances the contour from these signals. 26 is connected, and the enhancer 26 is provided with a signal processing circuit 28 for performing various processes for monitor output.
[0015]
The embodiment is configured as described above. First, when an object to be observed illuminated by the irradiation light from the distal end of the scope is imaged by the CCD 10, an output signal from the CCD 10 is sampled and amplified by the CDS / AGC 12. The digital signal is supplied to the DSP 16 through the A / D converter 14. In the DSP 16, Y signals subjected to various image processing and RY and BY C (color difference) signals are formed. The Y signals and the C signals are converted into R, G, and B signals by a color conversion circuit 18. Each color signal is converted.
[0016]
Of these, the G signal is output to the enhancer 26, which is a contour emphasis circuit, and is also supplied to the differentiating circuit 20. The differentiating circuit 20 corresponds to the position of the blood vessel based on this G signal (FIG. 2). The differential signal shown in C) is obtained. This differential signal is amplified by the gain circuit 22 at a predetermined amplification factor g and supplied to the blood vessel enhancement circuit 24 as its gain signal. In the blood vessel enhancement circuit 24, as described above, the R signal and the B signal are amplified by the differential signal as the gain signal (or multiplied by the differential signal as a coefficient) to emphasize the blood vessel portion in FIG. 3A. 3B is formed (these are shown as signals on the horizontal line La in FIG. 2A). The R and B signals are supplied to the enhancer 26 together with the G signal output from the color conversion circuit 18 and subjected to contour enhancement processing. Then, the signal processing circuit 28 performs various processes for monitor output. Applied.
[0017]
FIG. 4 is a diagram for explaining the color formation of the blood vessel part. FIG. 4A shows an image based on the R signal [FIG. 3A] output from the blood vessel emphasizing circuit 24. FIG. 5R, and as shown in the figure, a blood vessel (a portion where both lines run side by side) is displayed by a black portion of a dotted line and a red portion 3r of a one-dot chain line. FIG. 4B is an image 5B based on the B signal [FIG. 3B] output from the blood vessel emphasizing circuit 24. In this case as well, a dotted black portion and a two-dot chain blue portion 3b are used. It becomes an image in which blood vessels are displayed. FIG. 4C shows an image of the G signal output from the color conversion circuit 18, and when these RGB signals are combined, as shown in FIG. The blood vessel 3 composed of the portion and the solid line RGB composition unit is displayed.
[0018]
Thus, finally, in the monitor image, the blood vessels (capillaries) 3 are clearly displayed in the mucous membrane 2 with good contrast, and as a result, the running state and concentration state of the blood vessels 3 are good. In addition, the diagnosis of the lesion, the identification of the cancer tissue, and the like are performed well with reference to the running state of the blood vessel 3 and the like.
[0019]
In the above-described embodiment, the R (red) signal and the B (blue) signal are amplified based on the differential signal in the blood vessel enhancement circuit 24. However, it is possible to enhance the blood vessel by amplifying only this R signal. In the differentiation circuit 20, the differential signal is obtained based on the G signal, but the B signal may be input to generate a differential signal, and the blood vessel enhancement processing may be executed based on this. That is, the present invention detects the presence (position) of a blood vessel from an image signal other than red, which is the main color of the blood vessel, and can use a color signal other than the G signal.
[0020]
【The invention's effect】
As described above, according to the present invention, a differential signal obtained by differentiating, for example, the G signal other than the R signal that is the main color signal of the blood vessel is generated and amplified, and at least the R signal is amplified based on the differential signal. Because the blood vessels are emphasized by doing so, the blood vessels can be clearly displayed on the monitor with high contrast against other tissues such as mucous membranes, and provide useful information for observation and diagnosis of the observed object Is possible.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a main configuration of an electronic endoscope apparatus according to an embodiment of the present invention.
FIG. 2 is obtained by each circuit of the embodiment. FIG. (A) is the G signal image, FIG. (B) is the signal level of the horizontal line La of the G signal image of FIG. These are figures which show the differential signal of G signal of figure (B).
FIG. 3 is a diagram illustrating an R signal [FIG. (A)] and a B signal [FIG. (B)] of a horizontal line La output from the blood vessel emphasizing circuit of the embodiment.
4A and 4B are images obtained by each circuit according to the embodiment. FIG. 4A is an R signal image, FIG. 4B is a B signal image, FIG. C is a G signal image, and FIG. It is a figure which shows an image.
FIG. 5 is a diagram illustrating an enlarged image of an object to be observed that is captured and displayed by the electronic endoscope apparatus.
[Explanation of symbols]
10 ... CCD, 16 ... DSP,
18 ... color conversion circuit, 20 ... differentiation circuit,
22 ... Gain circuit, 24 ... Blood vessel enhancement circuit.

Claims (2)

A color signal forming circuit for forming a predetermined color signal based on a signal obtained by the image sensor;
A differentiating circuit for differentiating a predetermined color signal other than red obtained by the color signal forming circuit to generate a differentiated signal;
A gain circuit for amplifying the differential signal output from the differential circuit;
An electronic endoscope apparatus comprising: a blood vessel enhancement circuit that amplifies at least a red signal other than the predetermined color signal based on a differential signal output from the gain circuit to enhance a blood vessel. The color signal forming circuit forms red, green and blue color signals, the differentiating circuit performs a differentiation process on the green signal, and the blood vessel emphasizing circuit amplifies the red and blue signals with the differentiated signal. The electronic endoscope apparatus according to claim 1, wherein:

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