JPH10210454A - Image processor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To recognize an image after being processed correctly by properly eliminating the image data of a part in which no accurate image processing result is obtained. SOLUTION: This unit used for an endoscope or the like detects an amount of a hemoglobin index IHb in an image to display it in pseudo-color, so as to apply image processing to the image so as to easily identify a lesion or the like. An invalid region elimination part 4 that eliminates an region having improper data for image processing as an invalid region has an invalid region detection part 9 and an invalid region extension part 10. The invalid region detection part 9 discriminates whether or not the region is an invalid region such as a halation part or a dark part where an accurate arithmetic result is not obtained based on a signal level of an inputted image signal, and after the invalid region extension part 10 extends the invalid region by a prescribed region, based on an outputted from the invalid region detection part 9, the part 10 outputs only an image signal of a pixel to be made as a valid region and the calculation of the IHb amount and image processing of pseudo-color display are conducted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image processing apparatus for performing predetermined image processing on an image such as an endoscope image in order to improve visibility.

[0002]

2. Description of the Related Art Conventionally, for example, in an endoscope apparatus or the like, image processing such as color emphasis is performed on an endoscope image or the like obtained by an endoscope using an image processing apparatus, and the image processing is performed at the time of diagnosis. For example, visibility is improved. In an image processing device for an endoscope, accurate calculation data cannot be obtained for data of a halation portion which is blurred due to an excessive amount of illumination in an image or a dark portion which is dark due to a small amount of illumination. It is common practice to exclude data from the arithmetic processing as inappropriate data for the processing. For example, in the image processing apparatus disclosed in Japanese Patent Application Laid-Open No. Hei 3-21186, a case where the signal level deviates from a predetermined signal level is set as an invalid area so that it can be distinguished from other valid areas. So that highly relevant information can be obtained.

[0003]

However, in the conventional image processing apparatus, when an image is obtained by using a frame sequential endoscope apparatus, a color shift occurs due to a principle factor thereof. When the arithmetic processing is performed on data around an invalid area such as a halation part during processing, accurate data may not be obtained in some cases. For this reason, when the calculation result is displayed in a pseudo color, a color change around a portion removed as an invalid area may look like a lesion, and such an artifact may make it difficult to observe the image. There was a problem that was.

On the other hand, when a certain threshold value is used to remove the data of the halation portion and the dark portion so as not to generate the above-mentioned artifacts, the edge of the removed portion may be affected by noise or the like. In some cases, the image was jagged, making it difficult to see when observing with a moving image. In addition, there is a possibility that a normal region other than the periphery of the halation portion or the dark portion may be erroneously removed as an invalid region, and there is a problem that a region to be observed may be removed.

The present invention has been made in view of these circumstances, and it is possible to reliably and appropriately remove image data in a portion where an accurate calculation result cannot be obtained at the time of image processing, thereby preventing the occurrence of artifacts due to image processing. It is another object of the present invention to provide an image processing apparatus capable of preventing missing of image data of a desired portion that an observer wants to observe, and enabling an image after processing to be correctly recognized.

[0006]

According to the present invention, there is provided an image processing apparatus for performing a predetermined process on an input image signal, wherein an unprocessed portion in the image signal is determined based on a signal level of the image signal. Non-processing part specifying means to specify, based on the specifying information of the non-processing part specifying means,
A non-processing part extending means for expanding a non-processing part in the image signal by a predetermined area; and an image processing means for performing image processing based on the image signal in which the non-processing part is extended by the non-processing part expanding means. Things.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 6 relate to a first embodiment of the present invention, FIG. 1 is a block diagram showing a configuration of an image processing apparatus, FIG. 2 is a block diagram showing a configuration example of an IHb calculation unit, and FIG. FIG. 4 is an explanatory diagram showing a setting example of corresponding coloring, FIG. 4 is a block diagram showing a configuration of an invalid area removing unit,
FIG. 5 is a block diagram showing the configuration of the invalid area extension unit in FIG. 4, and FIG. 6 is an operation explanatory view showing an example of the distribution of the extended invalid area in the processed image.

In this embodiment, an example of the configuration of an image processing apparatus for an endoscope which performs image processing on an endoscope image obtained by an endoscope will be described. The image processing apparatus 1 performs image processing for displaying a hemoglobin index (hereinafter, referred to as IHb) correlated to a hemoglobin pigment obtained from an endoscope image in a pseudo color, and enabling observation of a change in the amount of IHb in a lesion or the like. It is a device that performs.

As shown in FIG. 1, an image processing apparatus 1 converts an analog input image signal into a digital signal.
A D conversion unit 2, an inverse gamma correction unit (γ ') 3 for performing an inverse gamma correction on the output of the A / D conversion unit 2, and an area having inappropriate data for performing image processing as an invalid area An invalid area removing unit 4 for removing, an IHb calculating unit 5 for calculating an IHb amount by calculation, a pseudo color allocating unit 6 for setting a display color according to the IHb amount, and gamma correction for an output of the pseudo color allocating unit 6 And a D / A converter 8 for converting a digital signal into an analog output image signal.

The operation of the image processing apparatus 1 according to the embodiment having the above-described configuration will be described. The endoscope image captured by the endoscope is input to the image processing device 1 and subjected to image processing for performing pseudo color display indicating the IHb amount. First, since the image signal of the endoscope image is digital signal processing in the image processing apparatus 1, the A / D converter 2
Is converted from an analog signal to a digital signal. The gamma correction applied to the endoscope image by the inverse gamma correction unit 3 is removed from the image signal converted into the digital signal. After that, the invalid area removing unit 4
Data in an unsuitable region corresponding to a halation portion, a dark portion and a peripheral portion thereof is removed. The method of removing the invalid area will be described later.

When the invalid area in the image is removed by the invalid area removing section 4, the IHb calculating section 5 calculates the I
The Hb amount is calculated. The calculation formula for calculating the IHb amount is as shown in the following formula (1).

IHb = 32 × Log (R / G) (1) where R: signal level of R image G: signal level of G image The calculation of the IHb amount is performed using a ROM or as shown in FIG. It can be calculated using a simple arithmetic circuit. For example, in the arithmetic circuit of FIG. 2, after dividing the signal level of the G image to the signal level of the R image by the division circuit 31, the logarithmic conversion circuit 32 performs logarithmic conversion, and the multiplication circuit 33 multiplies a constant 32. As a result, IHb
The quantity is required.

The IHb amount obtained for each pixel is input to the pseudo color allocating unit 6, where the calculated IHb amount is calculated.
The color to be displayed in the pseudo color is determined based on the amount. FIG.
Shows an example of setting of coloring corresponding to the amount of IHb, and is an example in the case where the display color is set by dividing the IHb amount into six stages. In this case, pink,
Red, yellow, green, cyan, and blue are assigned. The pseudo-color display colors are allocated by using a ROM or the like, and R, G, B representing each color as described above according to the input IHb amount.
If data is output, it can be easily performed.

When it is desired to observe a more detailed change in the amount of IHb, it is sufficient to divide the IHb amount into 8, 16, 32, etc., and to color each. Also, when it is desired to display changes in details in six colors, the observer wants to display I
This can be realized by designating a narrow range of the Hb amount.

As described above, the image signal of the IHb amount distribution image assigned as the pseudo color is subjected to gamma correction by the gamma correction unit 7 so that it has a linear characteristic when displayed on a monitor. Then, the image signal of the corrected IHb amount distribution image is converted from a digital signal to an analog signal by the D / A converter 8 and output from the image processing device 1.

Next, the configuration and operation of the invalid area removing section 4 will be described in detail. As shown in FIG. 4, the invalid area removing unit 4 includes an invalid area detecting unit 9 and an invalid area expanding unit 10.

The image signal from the inverse gamma correction section 3 input to the invalid area removing section 4 is input to the invalid area detecting section 9 and the invalid area extending section 10. The invalid area detection unit 9 determines, based on the input image signal, whether or not an area where an accurate calculation result such as a halation part or a dark part cannot be obtained by referring to the signal level or the like, and determines whether the area is an invalid area. “0” is output for the determined pixel, and “1” is output for the pixel determined as the effective area. The invalid area extension unit 10 expands the invalid area by a predetermined area based on the output of the invalid area detection unit 9, and then, among the input image signals, only the image signals of the pixels that are regarded as valid areas are IHb
It is output to the calculation unit 5. Note that a 0 level is output as the image signal of the pixel set in the invalid area.

FIG. 5 shows the configuration of the invalid area extension unit 10.
The invalid area extension section 10 includes line memories 12 and 13 for temporarily storing the output of the invalid area detection section 9, delays 14 to 19 for signal delay, a multiplication section 20 for multiplying input signals, and an output section. Selector 21 for selecting an image signal to be applied
And a memory 22 for storing the image signal input from the inverse gamma correction unit 3 to the invalid area removal unit 4.

The invalid area extension unit 10 refers to the image signal of an adjacent pixel from the input image signal, and if a 0-level signal indicating the invalid area exists in the adjacent pixel, the invalid pixel is also displayed. 0 level is output as an invalid area. At this time, the multiplication unit 20 multiplies the input nine signals, and the multiplication unit 20 includes the line memory 1
Signals of 3 × 3 adjacent nine pixels are input by 2, 13 and delays 14 to 19. If there is a 0 level signal in this area, the calculation result is “0”. That is, 3 × 3
When there is an invalid area in an adjacent pixel in the area, the center pixel can be also set as an invalid area.

FIG. 6 shows an example of the distribution of the invalid area extended by the invalid area extension section 10. As shown in FIG. In FIG. 6, “0” is a pixel indicating an invalid area, “1” is a pixel indicating an effective area, the left side is an image input to the invalid area expanding section 10, and the right side is output from the invalid area expanding section 10. The distribution of each invalid area of the image is shown. As in this example, a pixel in which a pixel adjacent in any of the up, down, left, right, and oblique directions is at the 0 level is also output as the 0 level.

The distribution of the invalid area expanded in this way is input to the B terminal and the S terminal of the selector 21 and
One of the signal input to the terminal and the image signal input to the A terminal is selected by the selector 21 and output to the IHb calculation unit 5. Of the entire area of the image, the pixels determined to be invalid areas are input to the B terminal, that is, a 0-level signal is output, and the pixels determined to be valid areas are input to the A terminal, that is, the input image signal is output. Is done. Here, the memory 22 has a function of delaying the input image signal by the time required for the operation for expanding the invalid area.

As described above, when calculating the IHb amount, a portion where accurate calculation data such as a halation portion or a dark portion cannot be obtained is removed as an invalid region, and the invalid region is extended to peripheral pixels. By re-setting, it is possible to appropriately remove the image data of the part where the accurate calculation result is not obtained at the time of the image processing, and it is possible to remove the influence of the color shift generated around the halation part and the like. Accurate calculation data can be obtained.

Further, in the present embodiment, since data around a defective portion such as a halation portion is largely removed, a color change due to an artifact which has conventionally occurred around a halation portion is reduced, and a change due to a lesion portion is reduced. It is possible to eliminate the risk of misunderstanding. In addition, since the edge removed as an invalid area is smoothed, the edge does not become jagged as in the conventional processing result. As a result, artifacts around the removed part are reduced. Since the number is reduced, it is possible to provide an image that can be easily observed.

In this embodiment, unlike the case where the signal level regarded as an invalid area is extended to remove artifacts around a defective part, a normal part other than a halation part or a dark part is regarded as an invalid area. Therefore, it is possible to prevent a problem that an area of a portion that the observer wants to observe is mistakenly set as an invalid area.

FIG. 7 is a block diagram showing the configuration of the invalid area removing section according to the second embodiment of the present invention. In the second embodiment, an example in which the configuration of the invalid area removing unit in the image processing apparatus of FIG. 1 is changed will be described. The invalid area removing section 30 is provided in the image processing apparatus for an endoscope, and removes invalid areas such as a halation section and a dark section from an input image by a method different from that of the first embodiment. The basic configuration and operation of the image processing apparatus are the same as in the first embodiment, and a description thereof will be omitted.

The invalid area removing section 30 includes a video RAM (VRAM) 24 for storing an input image signal, a CPU 25 for controlling each section, and an I / O for controlling data output to the B and S terminals of the selector 27. A port 26, a selector 27 for selecting an image signal to be output, and an inverse gamma correction unit 3.
And a memory 28 for storing an image signal input to the invalid area removing unit 30 and a bus 29 connecting the VRAM 24, the CPU 25, and the I / O port 26.

The image signal input to the invalid area removing unit 30 is input to the VRAM 24 and the memory 28. VRA
The CPU 25 determines whether or not the input image signal taken into the M24 is a region where accurate calculation data such as a halation portion or a dark portion cannot be obtained based on a signal level or the like. "1" is rewritten to "0".

Next, if the data of “0” exists in the 3 × 3 area, that is, in the pixel adjacent to the center pixel, the CPU 25 performs the mask processing of 3 × 3, and also the data of the center pixel. The invalid area is extended by rewriting to “0”. The distribution of the invalid area data obtained in this way is the same as that of FIG. 6 described in the first embodiment.
The mask processing is not limited to the 3 × 3 mask processing, and may be performed in a 5 × 5 or more area.

The distribution of the invalid area expanded in this way is sequentially read out from the VRAM 24 for each pixel, and
The signal is input to the B terminal and the S terminal of the selector 27 via the O port 26. On the other hand, an image signal is input from the memory 28 to the A terminal of the selector 27. The selector 27 selects one of the input signal of the B terminal and the input signal of the A terminal as a signal to be output based on the value input to the S terminal, and outputs the selected signal to the IHb calculation unit 5. That is, "0" is S
When the signal is input to the terminal, the signal input to the terminal B is changed to “1”.
When is input to the S terminal, a signal input to the A terminal is output. Therefore, of the whole area of the image, the pixels determined to be valid areas output the image signal input to the A terminal, and the pixels determined to be invalid areas output the 0 level signal input to the B terminal. You.

Here, the memory 28 has a function of delaying an input image signal by a time required for detecting an invalid area by the CPU 25 and expanding the invalid area. In addition,
If the above-described invalid area detection and extension processing are performed within the retrace period of the video signal, processing with a moving image can be performed.

With the above configuration, the image signal from which the invalid area has been removed is output to the IHb calculating section 5.

As described above, in the configuration of the second embodiment, the same operation and effect as those of the first embodiment can be obtained.
When performing pseudo color display by calculating the amount of b, even when processing an image obtained by a frame sequential type endoscope apparatus, even when processing an image obtained by a peripheral part such as a halation part, it is possible to reduce color shift. The influence can be removed, and more accurate calculation data can be obtained.

[Supplementary Notes] (1) In an image processing apparatus for performing a predetermined process on an input image signal, based on a signal level of the image signal,
A non-processing part specifying unit that specifies a non-processing part in the image signal; a non-processing part expanding unit that expands the non-processing part in the image signal by a predetermined area based on the specifying information of the non-processing part specifying unit; An image processing device comprising: an image processing unit that performs image processing based on an image signal whose non-processing part has been expanded and set by the non-processing part expansion unit.

(2) Invalid area detecting means for detecting an invalid image area inappropriate for arithmetic processing based on the signal level of the input image signal, and invalid image area information detected by the invalid area detecting means. Based on an invalid area extending means for extending and setting an invalid image area by a predetermined area, and an invalid image area extended by the invalid area extending means.
An image processing device comprising: an arithmetic unit that performs arithmetic processing for image processing on the image signal.

(3) The image processing apparatus according to appendix 1, wherein the non-processing portion specifying means detects a halation portion and a dark portion in the image signal as non-processing portions.

(4) The non-processing portion expanding means detects that an adjacent pixel in the image signal is a non-processing portion based on the specifying information of the non-processing portion specifying means, and expands the non-processing portion. The image processing apparatus according to claim 1, wherein the image processing is performed.

(5) The non-processed part expanding means, based on the identification information of the non-processed part specifying means, sets an extended pixel as a non-processed part when an adjacent pixel in the image signal has a non-processed part. 2. The image processing apparatus according to claim 1, wherein

[0038]

As described above, according to the present invention, it is possible to reliably and appropriately remove image data in a portion where an accurate operation result cannot be obtained during image processing, thereby preventing the occurrence of artifacts due to image processing. There is an effect that it is possible to prevent a loss of image data of a desired portion to be observed by an observer, and to correctly recognize a processed image.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an image processing apparatus according to an embodiment of the present invention.

FIG. 2 is a block diagram illustrating a configuration example of an IHb calculation unit.

FIG. 3 is an explanatory diagram showing a setting example of coloring corresponding to an IHb amount;

FIG. 4 is a block diagram illustrating a configuration of an invalid area removing unit according to the first embodiment.

FIG. 5 is a block diagram showing a configuration of an invalid area extension unit in FIG. 4;

FIG. 6 is an operation explanatory diagram showing an example of a distribution of an extended invalid area in a processed image.

FIG. 7 is a block diagram illustrating a configuration of an invalid area removing unit according to a second embodiment.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 image processing device 3 inverse gamma correction unit 4 invalid region removal unit 5 IHb calculation unit 6 pseudo color allocation unit 7 gamma correction unit 9 invalid region detection unit 10 invalid region extension unit

Claims (1)

[Claims] 1. An image processing apparatus for performing predetermined processing on an input image signal, comprising: a non-processing part specifying unit that specifies a non-processing part in the image signal based on a signal level of the image signal; A non-processing part expanding means for expanding a non-processing part in the image signal by a predetermined area based on the specifying information of the part specifying means; and an image processing based on the image signal in which the non-processing part is extended by the non-processing part expanding means An image processing apparatus, comprising: