JP2014124484A - Imaging apparatus, endoscope apparatus, and biological pattern emphasis processing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an imaging apparatus and an endoscope apparatus, capable of displaying a biological pattern in emphasis.SOLUTION: An imaging apparatus includes a white balance part and a biological pattern emphasis processing part. In the imaging apparatus, the white balance part controls color with respect to an input RGB screen image signal, and the biological pattern emphasis processing part emphasizes a biological pattern by performing an emphasis processing for emphasizing blue or green out of three primary colors with respect to output from the white balance part.

Description

Embodiments described herein relate generally to an imaging apparatus, an endoscope apparatus, and a biological pattern enhancement processing method that perform enhancement processing particularly suitable for imaging a living body on an image signal output from an image sensor.

In a conventional imaging apparatus, for example, an endoscope apparatus, a scope is inserted into a patient's body, and imaging is performed while illuminating the affected area with a light source. However, when imaging a living body such as an affected area, the entire body is reddish and the contrast is low, so that the pattern of unevenness on the body surface, blood vessels, etc.
Identification) is difficult.

As a technique related to an endoscopic technique for emphasizing a living body pattern when photographing a living body pattern, a method of compensating for contrast using a specific narrow band light is considered. These methods use the principle that when the inside of the body is observed with narrow-band light such as blue light (around 415 nm) or green light (around 540 nm), patterns such as irregularities on the body surface and blood vessels are easy to see. It is. Specifically, since blue light (around 415 nm) is strongly absorbed by blood, the surface irregularities of the living body and the characteristics of capillaries can be captured well. The green light (near 540nm)
There is a tendency that the contrast between the observation of thick blood vessels in the deep part of the living body and the capillaries on the surface of the mucosa can be emphasized.

JP 2006-325974 A JP 2004-167008 A Japanese Patent Publication No. 6-24505

However, in the method of observing using specific narrow band light, in addition to a normal RGB camera, an optical mechanism for narrow band is necessary, and a decrease in light amount due to narrow band is a problem.

The present embodiment provides an imaging apparatus and an endoscope apparatus that can view patterns such as irregularities and blood vessels on a body surface without using another optical mechanism other than an RGB camera even when a living body is imaged. Objective.

The imaging device according to the embodiment includes a white balance unit and a biological pattern enhancement processing unit. Here, the white balance unit adjusts the hue of the input RGB video signal, and the biological pattern enhancement processing unit emphasizes the three primary colors blue or green with respect to the output from the white balance unit. The biological pattern is emphasized by performing the enhancement process.

The block diagram of the endoscope apparatus which concerns on embodiment. The block block diagram of the video processing part in 1st Embodiment. The figure which shows the example of a setting of the biometric emphasis matrix circuit which concerns on embodiment. The block block diagram of the video processing part in 2nd Embodiment. The block block diagram of the video processing part 32 in 3rd Embodiment.

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

In this embodiment, a configuration of a rigid endoscope apparatus will be described as an example of an imaging apparatus. FIG.
These are figures which show the structure of the endoscope apparatus 1 (it is hereafter described as the endoscope apparatus 1) which concerns on embodiment. In this embodiment, a CMOS (Complementary Metal Oxide Semicond) is used as an image sensor.
uctor) An image sensor will be described as an embodiment.
d Device) An image sensor may be used. In the following description, it is assumed that the image includes a moving image and a still image.

The endoscope apparatus 1 is provided with an objective lens 10a at the tip, a scope 10 to be inserted into the body to be inspected, and a CMOS image sensor 20a (hereinafter, referred to as an imaging plane of the objective lens 10a).
An RGB image signal (hereinafter simply referred to as an image signal) captured by the image sensor 20a) is output to the CCU via the camera cable 50, and the image signal output from the head 20 is processed. A CCU (camera control unit) 30, a light source 40 (light source) that illuminates the imaging range, an optical fiber 60 for introducing light from the light source 40 to the distal end of the scope 10, and a captured image signal And a monitor 70 for displaying a corresponding image.

The head 20 includes an image sensor 20a, a connection terminal 21, an I / F circuit 22, and a memory 23.
It comprises. The image sensor 20a is a digital color CMOS image sensor compatible with full HD (high density). In this embodiment, the image sensor 20a is driven by progressive scan, but may be driven by interlaced scan.

The image signal output from the image sensor 20a is transmitted to the CCU 30 via the camera cable 50 as a digital signal. At this time, R (red), G (green), and B (blue) image signals (specifically, density value (gradation) data of pixels constituting the screen) use separate signal lines. Is transmitted. For this reason, it is possible to display a high quality image as compared with the conventional analog RGB transmission.

The CCU 30 includes an I / F unit 31, a video processing unit 32, an image output unit 33, and the like. The image signal processing circuit 33 includes an image signal processing unit 33a and a synchronization signal generation unit 33b. The image signal processing unit 33 a processes the image signal output from the I / F circuit 32 and outputs the processed image signal to the image output circuit 33.

The image output circuit 33 converts the image signal into an image signal suitable for the monitor 70. For example, the image output circuit 33 converts the image output circuit 33 into a digital RGB image signal, DVI (digital visual interface), or the like.
Output to 0.

The camera cable 50 accommodates a signal line for transmitting and receiving an image signal and a control signal between the head 20 and the CCU 30, a power line for supplying power from the CCU 30 to the head 20, and the like.

(First embodiment)
In this embodiment, in order to perform biological pattern emphasis processing in an endoscope three-band camera (RGB camera), the video processing unit 32 performs white balance (hereinafter referred to as WB) and matrix processing for emphasizing the biological pattern. It is the composition which combined.

  FIG. 2 is a block configuration diagram of the video processing unit 32 in the first embodiment.

Reference numeral 34 denotes a white balance adjustment circuit. The white balance adjustment circuit 34 is connected to the CCU 3
White balance adjustment is performed between R, G, and B signals input via the 0 IF unit 31.
The white balance adjustment circuit 34 can be applied to either one-touch WB or automatic tracking WB. By executing one-touch WB or automatic tracking WB, RG on the subject
The values of the respective video signals of the B signal can be made to approximate values. As a result, variations in the spectral intensity of the light source 40 and the spectral sensitivity of each channel can be approximately normalized. In general, since a living body is reddish, it is generally not a target for convergence such as automatic tracking WB. For this reason, the white balance adjustment circuit 34 of the present embodiment is configured to have a sufficient convergence range for the living body.

Reference numeral 35 denotes a biological enhancement matrix circuit. In general, as characteristics when imaging a living body, blue light tends to capture the characteristics of the surface irregularities and capillaries of the living body, and green light tends to capture the characteristics of deep blood vessels inside the living body. For this reason, the coefficient of the matrix processing of the biological enhancement matrix circuit 35 performs processing for enhancing green (G) and blue (B) with respect to red (R). As an example of the coefficient of the biological enhancement matrix circuit 35, when a linear matrix (for example, G ′ = G + α * (RG) + β * (BG)) is used, the average portion of the subject is maintained in WB and is achromatic. Become. And since the part where the balance of RGB differs will be colored, a biometric pattern becomes easier to see.

Reference numeral 36 denotes a switch circuit. A circuit that switches whether the video signal to be output to the monitor 70 is a video signal in the biological enhancement mode that is an output signal of the biological enhancement matrix circuit 35 or whether the output of the white balance adjustment circuit 34 is output as it is (normal mode). is there. The switch circuit 36 can be switched between a “biological pattern enhancement mode” in which a biological pattern is emphasized and a “normal mode” in which the biological pattern is not emphasized by an operation unit (not shown).

  FIG. 3 is a diagram illustrating a specific setting example of the biological enhancement matrix circuit 35.

Here, the biological enhancement matrix circuit 35 is separated into two, and is separated into a G enhancement matrix circuit 37 and a B enhancement matrix circuit 38.

First, the G-enhanced linear matrix circuit 37 considers “3 * GRB” as a coefficient setting example (when α = −1 and β = −1 are substituted into the above equation). This is the case when there are deep blood vessels
The G output is lower than the output and B output, and the filter is expected to emphasize it.

On the other hand, “3 * BRG” (when α = −1 and β = −3 is substituted into the above equation) is considered as an example of setting the coefficients of the B-enhanced linear matrix circuit 38. With this setting, surface irregularities and capillaries can be emphasized.

Assign these to the output. Specifically, the output of the G-enhanced linear matrix circuit 37 is input to Rch because the deep blood vessels are thick and can be easily identified as colors (thus, the deep blood vessels become dark cyan color output). On the other hand, the output of the B-enhanced linear matrix circuit 38 is assigned to B′ch and G′ch so as to be close to the luminance information because the unevenness and capillaries are thin. ),
When the stitch circuit 36 is turned on, the combination of the WB and the matrix becomes a biological pattern enhancement camera (biological enhancement mode), and when turned off, a normal RGB camera (normal mode) is obtained.

As described above, in the present embodiment, in consideration of the fact that red light tends to scatter in the human body and there is a small amount of fine information other than the luminance component, the G enhancement matrix and the B enhancement matrix are used. The pattern can be highlighted and displayed. The switch circuit 36 is turned on.
It is possible to easily realize functions such as / OFF or operating only the enhancement amount adjustment parameter.

In this embodiment, only the ON / OFF setting of the switch circuit 36 that is the simplest is possible, and the linear matrix circuit has two parameters (G enhancement side: 1 parameter, B enhancement side: 1 parameter).
However, the present invention is not limited to this. For example, the linear matrix circuit may further have a degree of freedom, and the amount of enhancement may be made variable by four parameters (G enhancement side: 2 parameters, B enhancement side: 2 parameters). As an example of setting in this case, G enhancement = “G + k1 * (GR) + k2 * (GB
) ”, B enhancement =“ B + k3 * (BR) + k4 * (BG) ”.

As another setting method for the four parameters, G enhancement = “G + k1 * (GR) + k1 * (GB)”
, B enhancement = “B + k2 * (BR) + k2 * (BG)”.

In another setting method, it is possible to make the amount of enhancement variable with two parameters such as G enhancement = “G + k1 * (GR)” and B enhancement = “B + k2 * (BR)”. .

(Second Embodiment)
As a second embodiment, an embodiment in which contour enhancement processing is applied to biological pattern enhancement processing will be described.

In general, the contour emphasis processing emphasizes a portion where the luminance signal Y changes a large value. As a circuit, “the luminance signal Y is passed through the HPF to extract a high frequency component, is multiplied by an amplification coefficient, and is added to the original signal. It is a configuration such as “Yes”. In particular, in an endoscope, it is necessary to compensate for the degradation of a high-frequency signal due to a scope, and therefore there is a tendency that contour enhancement processing is strongly used. ”,“ B / R signal ”.

FIG. 4 is a block diagram of the video processing unit 32 according to the second embodiment. The description of the same parts as those in FIG. 2 is omitted.

In the present embodiment, a red color (not easily affected by a biological pattern)
The biometric pattern is emphasized by emphasizing a portion where the relative value change of green (G) or blue (B) is large with R) as a reference.

As a specific circuit, first, G / R is obtained by the contour reference generation unit 71. Here, since division is heavy processing, G enhancement is realized using a LOG table as in the contour reference generation unit 71. A contour is extracted by the contour extraction HPF 72 from the output of the contour reference generation unit 71, multiplied by a predetermined coefficient K, and added to the signal R.

Similarly, the B / R signal is multiplied by the contour reference generation unit 73, the contour extraction HPF 74, and the coefficient K.
The obtained contour extraction signal is added to the signal G and the signal B, respectively. Here, by manipulating the amplification coefficient K, it becomes possible to change the amount of enhancement of deep blood vessels and the like.

Also in the present embodiment, since the switch circuit 36 is provided in the subsequent stage, the video signal output to the monitor 70 is the video signal in the biological enhancement mode that is the output signal of the biological enhancement matrix circuit 35, or white Whether the output of the balance adjustment circuit 34 is output as it is (normal mode) can be switched. Similarly to FIG. 2, the switch circuit 36 can be switched between a “biological pattern emphasis mode” for emphasizing a biometric pattern and a “normal mode” for not emphasizing the biometric pattern by an operation unit (not shown). .

(Third embodiment)
Another method in which contour enhancement processing is applied to biological pattern enhancement processing will be described as a third embodiment.

FIG. 5 is a block diagram of the video processing unit 32 in the third embodiment. The description of the same parts as those in FIGS. 2 and 4 is omitted.

In the present embodiment, the average of the signal G and the signal B: (G + B) / 2 is divided by the signal R to perform contour extraction.

In the figure, the average of the signal G and the signal B is obtained by adding the signal G and the signal B to ½.
(G + B) / 2 is obtained. For this (G + B) / 2, the contour reference generator 74
Dividing by signal R. The division method is performed by taking LOG as in FIG. Thereafter, the contour extraction is performed by the contour extraction HPF 75, multiplied by a predetermined coefficient, and added to the signal R, the signal G, and the signal B, respectively.

Also in the present embodiment, since the switch circuit 36 is provided in the subsequent stage, the video signal output to the monitor 70 is the video signal in the biological enhancement mode that is the output signal of the biological enhancement matrix circuit 35, or white Whether the output of the balance adjustment circuit 34 is output as it is (normal mode) can be switched. Similarly to FIG. 2, the switch circuit 36 can be switched between a “biological pattern emphasis mode” for emphasizing a biometric pattern and a “normal mode” for not emphasizing the biometric pattern by an operation unit (not shown). .

In the present embodiment, since the same value is added not only to the G signal but also to the R signal and the B signal in this embodiment, an achromatic outline is effective.

(Other embodiments)
Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. The above embodiment can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 1 ... Endoscope apparatus, 10 ... Scope, 20 ... Head, 30 ... CCU, 31 ... I / F part, 3
2 ... Video signal processing unit, 33 ... Image output circuit, 40 ... Light source, 50 ... Camera cable, 60 ... Optical fiber, 70 ... Monitor, 34 ... White balance adjustment circuit, 35 ... Biological enhancement matrix circuit, 36 ... Switch circuit 37 ... G-enhanced Matrix, 38 ... B-enhanced Matrix, 71
73, 75 ... contour reference generation unit, 72, 74, 76 ... contour extraction HPF

Claims (15)

A white balance unit for adjusting the hue of the input RGB video signal;
An imaging apparatus comprising: a biometric pattern emphasis processing unit that emphasizes a biometric pattern by performing an emphasis process that emphasizes the three primary colors blue or green on the output from the white balance unit. The imaging apparatus according to claim 1, wherein the enhancement processing includes a linear matrix that enhances a G video signal and a linear matrix that enhances a B signal. The biological pattern enhancement processing unit
2. The image pickup apparatus according to claim 1, wherein the image pickup apparatus is an edge emphasis unit based on a ratio of a G video signal or a B video signal to an R video signal. 4. The contour enhancement unit according to claim 3, wherein the contour emphasizing unit is a contour emphasizing unit that detects a contour with respect to a signal obtained by dividing the G signal by the R signal and a signal obtained by dividing the B signal by the R signal and emphasizes the extracted contour. Imaging device. The imaging apparatus according to claim 3, wherein the contour emphasizing unit is a contour emphasizing unit that detects the contour of a signal obtained by dividing the average signal of the G signal and the R signal by the R signal and emphasizes the extracted contour. A white balance unit for adjusting the hue of the input RGB video signal;
An endoscope apparatus comprising: a biometric pattern emphasis processing unit that emphasizes a biometric pattern by performing an emphasis process that emphasizes the three primary colors blue or green on the output from the white balance unit. The endoscope apparatus according to claim 6, wherein the enhancement processing includes a linear matrix that enhances a G video signal and a linear matrix that enhances a B signal. The biological pattern enhancement processing unit
The endoscope apparatus according to claim 6, wherein the endoscope apparatus is contour enhancement means based on a ratio of a G video signal or a B video signal to an R video signal. 9. The contour emphasizing unit for emphasizing an extracted contour by detecting a contour of a signal obtained by dividing a G signal by an R signal and a signal obtained by dividing a B signal by an R signal. Endoscopic device. The endoscope according to claim 8, wherein the contour emphasizing unit is a contour emphasizing unit that enhances an extracted contour by detecting a contour of a signal obtained by dividing the average signal of the G signal and the R signal by the R signal. apparatus. For the input RGB video signal, the white balance is adjusted by the white balance unit,
A biometric pattern emphasis processing method in which a biometric pattern emphasis processing unit performs an emphasis process on the output from the white balance unit by emphasizing the three primary colors blue or green. 12. The biological pattern enhancement processing method according to claim 11, wherein the enhancement processing includes a linear matrix for enhancing a G video signal and a linear matrix for enhancing a B signal. The biological pattern enhancement process
12. The biological pattern enhancement processing method according to claim 11, wherein contour enhancement is performed based on a ratio of a G video signal or a B video signal to an R video signal. 14. The living body according to claim 13, wherein the contour enhancement is contour enhancement means for detecting a contour with respect to a signal obtained by dividing the G signal by the R signal and a signal obtained by dividing the B signal by the R signal, and enhancing the extracted contour. Pattern enhancement processing method. 14. The biometric pattern emphasizing process according to claim 13, wherein the contour emphasis is contour emphasizing means for emphasizing an extracted contour by detecting a contour of a signal obtained by dividing the average signal of the G signal and the R signal by the R signal. Method.

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