JPH04122359A - Image contour stressing processor - Google Patents

Abstract

PURPOSE:To obtain an image contour stress processing which allows the setting of a contour for a contour stress processing freely by enabling the setting of an optional area desired for the contour stress processing on an image and a frame surrounding the area. CONSTITUTION:When sigma dispersion value sigma is compared with two reference dispersion values sigma1 and sigma2, a specified ultrasonic signal is transmitted to or received with an object 24 to be inspected from a probe 10 and an echo signal received is stored by one screen portion serial into a memory 12 as image information. Image density level information stored is outputted as a notice pixel value (z) and a means 2 in an area near pixels of Xn containing (z). But the dispersion value sigma is determined based on the means near the pixels of nXn in a specified area and a square mean. A comparison/computation circuit 18 compares the dispersion value sigma with two different reference values sigma1 and sigma2 predetermined and a pixel value stressing circuit 22 performs a contour stress processing to set the notice pixel value larger when the dispersion value is larger than the pixel mean and smaller when it is smaller than the mean. This enables the setting of a specified area alone thereby obtaining a pixel display state subjected to a proper contour stress processing.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an image contour enhancement processing device using digital image processing technology, and in particular to an ultrasound image processing device for processing an ultrasound image of an affected area based on an echo signal from a subject, such as an ultrasound diagnostic device. The present invention relates to an image contour enhancement processing device that displays an image of an affected area and enhances the contour of a predetermined range of an image of an affected area.

[Background Art] In the medical field, ultrasonic diagnostic apparatuses that transmit and receive ultrasonic waves into a subject such as a living body to diagnose the inside of the subject are well known.

This type of device transmits pulsed ultrasonic waves that are output at a constant repetition rate into the subject, receives echo signals reflected from the subject, and performs this on a predetermined area. , for example, to obtain B-mode image information.

This information is then displayed as an image on a CRT display, thereby allowing tomographic images of the heart, liver, etc. to be observed. Image processing in such an ultrasonic diagnostic apparatus involves emphasizing the outline of an echo signal in an analog manner.

That is, by performing differential processing on the echo signal after detection and adding this differential signal to the original signal, the contour information in the echo signal is emphasized.
The shape and structure inside the subject are clearly displayed in images, which is useful in image diagnosis.

However, since this type of contour enhancement is a fixed process, it also emphasizes noise, speckles, etc., and there is a problem that the image lacks continuity as a two-dimensional image.

Therefore, the applicant of the present application has proposed an ultrasonic image processing apparatus using contour enhancement processing that solves all of the above-mentioned analog problems (Japanese Patent Application No. 63-317918).

In this contour enhancement method, contour enhancement is performed more accurately than in the past, and two-dimensional processing with connections between pixels is performed.

In other words, in this contour enhancement process, if the pixel of interest in a predetermined area is larger than the pixel average value, the value of the pixel of interest is set to be larger than the pixel of interest, and if the pixel of interest is smaller than the average pixel value, the value of the pixel of interest is set to be larger than the pixel of interest. Set smaller than the value.

As a result, in the diagnostic image, dark areas become darker, light areas become lighter, and outlines are expressed very clearly, especially when the variance value of the gray level for each pixel is smaller than the reference variance value. performs contour enhancement processing and outputs pixel values as they are, so signals such as noise and speckles are not emphasized and images can be displayed.

As a result, the diagnostician can obtain an image that allows easy diagnosis of the desired affected area.

[Problems to be Solved by the Invention] However, in such an edge enhancement processing method, the areas to be enhanced are originally areas with unclear outlines, and areas with clear outlines should not be emphasized. However, on the other hand, there is a problem in that areas with clear outlines are emphasized too much.

In other words, the reason is that the variance value of the surrounding area including the pixel of interest is calculated, and if that variance value exceeds only one reference value, it is judged as a boundary, and the larger the variance value, the more the contour This is because the pixel of interest is emphasized in the direction of emphasis.

Therefore, in the past, there was a drawback that when there was a large difference in shading, it was further emphasized, and it was sometimes difficult for the diagnostician to see the image of the affected area, and it was also difficult to diagnose. As a result, appropriate image contour enhancement processing is not performed, and the above-mentioned conventional contour enhancement processing is not performed with high accuracy.

Therefore, areas with small variance such as noise and speckles, and areas with clear contours from the beginning are not emphasized, and the variance value is adjusted within the standard based on two predetermined standard variance values. The present applicant has proposed an ultrasonic diagnostic image processing device that performs contour enhancement by
-117171).

As a result, in image contour enhancement processing, all conventional problems can be solved, and highly accurate image information that is extremely easy to diagnose can be obtained.

That is, this ultrasonic diagnostic image processing device calculates the variance value σ of the gray level around the pixel of interest, and uses this variance value σ and a predetermined reference variance value σ1°σ2 (σ1 × σ2).
The degree of contour enhancement is determined based on the magnitude relationship between the two.

Based on this size comparison, if σ, σ1, and σ2, no emphasis processing is performed, and if σ, σ, and σ2, emphasis processing approximately proportional to σ is performed, and if σ1, σ2, and σ, emphasis processing is performed approximately proportional to Performing inversely proportional emphasis processing, the reference variance value σ1. σ2
By changing , it is possible to perform contour enhancement processing on any shading difference region. As a result, appropriate contour enhancement processing is performed, and an image of the desired affected area that is easy for the diagnostician to diagnose is obtained.

However, since the above-mentioned contour enhancement processing was performed on the screen, it is not possible for the diagnostician to freely emphasize the contours of any part on the image, and depending on the diagnosis situation, for example, the contour of the affected part image can be enhanced. It was not possible to set only the range of the desired area and emphasize the outline.

That is, this is because one or two standard variance values σ1 and σ2 are uniquely determined in order to enhance the contour of the arbitrary region, and as a result, the degree of contour enhancement cannot be increased or varied. It is.

Therefore, the diagnostician may wish to freely select any region on the image, for example, only a partial region of the affected part image, depending on the diagnostic situation, and perform contour enhancement processing on only that region.

As a result, there has been a desire for diagnosticians to perform contour enhancement processing on only a portion of the image to obtain an image of the affected area that is easier to diagnose.

Purpose of the Invention The present invention has been made in view of the above-mentioned conventional problems.The purpose of the present invention is to set an arbitrary region on an image for which contour enhancement processing is desired and a frame surrounding the region, and to It is an object of the present invention to provide an image contour enhancement processing device that can perform processing to display a frame, and can freely set a contour enhancement processing area by not performing contour enhancement processing outside the area.

[Means for Solving the Problems] In order to achieve the above object, the present invention selects a group of pixels in a predetermined area centered on a pixel of interest in image information, and calculates the pixel average value of the group of pixels. a variance value calculating means for calculating a variance value based on the pixel value of the pixel of interest and the pixel average value; and a comparison determination means for determining whether the pixel value of interest is larger than the pixel average value based on the comparison determination result, and setting the pixel value larger if the pixel value of interest is larger than the pixel average value; pixel value emphasizing means for performing edge enhancement processing by setting the pixel value smaller; enhancement processing range selection means for selecting whether to perform the edge enhancement processing over the entire range on the screen or within a predetermined range; When performing the process within a predetermined range, an outline emphasis area setting means sets a variable area on the screen and performs the outline emphasis process on the set area, and whether or not to display a frame surrounding the area on the screen. and frame display selection means for selecting a frame display.

[Operations] With the above-described configuration, the image contour enhancement processing device of the present invention allows selection of whether to perform the contour enhancement processing over the entire range on the screen or within a predetermined range; When performing within the predetermined range, you can specify any variable area on the screen, set a frame surrounding the area, and select whether or not to display the frame on the screen. It becomes possible.

Therefore, the diagnostician can arbitrarily set a contour emphasis area on the screen according to the diagnosis, and only the image of the area can be contour-enhanced and displayed, and the frame surrounding the area can be displayed on the screen. Since the image can be displayed, the desired affected image part that has been subjected to the contour enhancement process can be easily confirmed, making the diagnosis extremely easy for the diagnostician.

[Embodiments] Hereinafter, preferred embodiments of the present invention will be described based on the drawings.

FIG. 1 shows contour enhancement f#! in an ultrasonic diagnostic image, which is an embodiment of the present invention. FIG. 2 is a circuit block diagram showing the device.

Explanation of the principle of contour enhancement processing The basic principle of the above contour enhancement process will be explained below.

In this embodiment, the variance value σ of the gray level in the vicinity including the pixel of interest is calculated, and a certain process is applied to the pixel of interest according to the magnitude of the variance value σ. The case where the value σ1°σ2 (σ1×σ2) is provided will be explained as an example.

In other words, if the variance value σ of a certain pixel of interest is smaller than σ1, no processing is performed, and if it exceeds σ1, the pixel value of interest is increased or decreased according to the exceeded size to adjust the degree of edge enhancement. This is the case.

Assuming that the pixel value of interest is 2, the average value of nxn neighbors including this pixel is Zn, and the pixel value after contour enhancement processing is 22, the contour enhancement process is expressed by the following equation.

zz−z ten KX (z−E) However, K−0・・・・・・・・・σkuσ (1)■ ni−KEX fl−(σ1/σ)) φ・・II jar・σ ≦σ≦σ (2) −KEX (
σ /σ)...σ2×σ (3) Also, σ−72
(E) However, KE-contour enhancement constant (1 to 5), σ1. σ2−
An arbitrary constant (σ1 × σ2) is used as a reference variance value, and Σ2 is the average value of the squares of the vicinity of the pixel value of interest 2.

Here, K in the above equation, zz-z+KX (zz), and σ1. The relationship with σ2 is shown in FIG.

That is, FIG. 5 is a characteristic diagram in which the degree of emphasis K on the vertical axis is determined with respect to the change in the dispersion value σ on the horizontal axis (lower limit value σ, upper limit value σ2 of the standard dispersion value). In addition, this curve has a characteristic that indicates an edge enhancement process that is approximately proportional to the variance value σ from σ1 to σ2, and a characteristic that indicates an edge enhancement process that is approximately inversely proportional to the variance value σ when the variance value σ is 02 or more. Become.

According to the second characteristic, parts with gentle shading (when the variance value σ is small) are emphasized according to their degree, and parts with strong shading (when the variance value σ is large) are not overemphasized. Appropriate contour enhancement processing can be performed.

Explanation of the configuration of the contour enhancement processing circuit Next, a specific circuit configuration of an ultrasonic diagnostic image processing apparatus to which such a principle is applied will be described with reference to FIGS. 1 and 2.

In the figure, this ultrasonic diagnostic image processing device includes a probe 1
0, a memory 12, a variance value calculation circuit 16 including an average value calculation circuit 14, a comparison/calculation circuit 18, a constant setting circuit 20, and a pixel value emphasis circuit 22. It is composed of an area inside/outside discrimination circuit 25 as an outline emphasis area setting means and a frame display means, which are two main structural elements, and a selector 27 as an emphasis processing range selection means.

That is, the sorter 27 is constituted by an electrical or mechanical changeover switch such as an input keyboard, and the sorter 27 determines whether the contour enhancement process is performed over the entire range on the screen or within a predetermined range. It is possible to select either to perform the contour enhancement process or to display the original image without performing the edge enhancement process.

As a result, the contour-enhanced image of the affected area and the original image can be displayed as desired and compared on the television screen.

Further, the area inside/outside discrimination circuit 25 is built into, for example, an input keyboard (input device) not shown, and when performing the edge enhancement process within a predetermined range, it can variably set an arbitrary area on the screen. However, the contour enhancement process is performed only on the set area.

Furthermore, a frame surrounding the area can be set, and it can be selected whether or not to display the frame on the television screen.

Furthermore, FIG. 2 shows the circuit configuration inside the area/inside/outside discrimination circuit 25, and this area/inside/outside discrimination circuit 25 determines whether or not an area and a frame are specified, and switches for setting the area. Circuit 50 and NAND circuits 61 to 68.8
9.90, a counting section 70 consisting of counters 71.72 and UP-DOWN counters 73 to 76, and an adder 81.8.
2. Arithmetic circuit 8 consisting of comparators 83 to 86 and discrimination circuit 87
It consists of 8.

That is, as shown in FIG. 2, the switch circuit 50
, a large number of switches 51 to 58 (eight in this embodiment) that can vary the vertical and horizontal directions and size in order to set an area on the screen when contour enhancement processing is performed within a predetermined range, and a setting area. It consists of a switch 59 for selecting whether or not to display a frame surrounding the frame, and a region setting switch RO 0 for setting whether or not to set an outline emphasis area.

Further, each of the NAND AND circuits 68. 8990 is
As shown in the figure, it is configured by combining an N01 circuit and an AND circuit, and the 0N-O from each of the switches 51 to 58 is
FF (0,1) signal or each NA via the N01 circuit
The two terminals are respectively input to one terminal of the ND circuit, and the clock 2 signal with a predetermined period is input to the other terminal.

Of course, by turning each switch 0N-OFF, NANDA
A predetermined voltage is supplied between each switch and the N01 circuit via a resistor R to perform an ND circuit.

The UP-DOWN counters 73 to 76 each input the output results of each NANDAND circuit connected to each of the switches 51 to 58, perform an UP count or a DOWN count according to this input, and perform an ON operation of each of the switches. A predetermined count value is output accordingly.

On the other hand, the counter 71 receives a horizontal synchronization signal in television scanning and a vertical synchronization signal via the N01 circuit,
It outputs the count value according to the horizontal synchronization signal.

The other counter 72 receives the clock 1 synchronization signal and the horizontal synchronization signal via the N01 circuit, and outputs the count value of the synchronization signal.

Then, the adder 81 adds the two-hand numerical value outputs from the UP-DOWN counters 73 and 74, and
2 adds the two-hand numerical value output from the UP-DOWN counter 75.76, and the comparator 83.84 inputs the counted value from the counter 71 and the addition result from the adder 81 and compares it. do. Further, the comparators 85 and 86 also perform comparison in the same manner as described above.

The discrimination circuit 87 includes each of the comparators 83 to 86.
It inputs the comparison results from and outputs two discrimination results.

As a result, the NANDAND circuit 90 inputs the determination result and also inputs the above-mentioned switches 59 and 60.
A frame setting signal and a region setting signal are output as a determination result only when a designation signal specifying the area or frame is input when is ON.

Description of operation of contour enhancement processing circuit The operation of the contour enhancement processing circuit shown in FIGS. 1 and 2 as described above will now be described.

Note that the operation of the contour enhancement process will be explained based on a comparison between the variance value σ and two different reference variance values σ1 and σ2.

First, a predetermined ultrasonic signal is transmitted from the probe 10 to the subject 2.
4, and the received echo signals are serially stored in the memory 12 for one screen as image information.

In this memory 12, grayscale information of each pixel is stored as a two-dimensional digital image.

The image gradation information stored in this memory 12 is
The pixel value z1 of interest is output from the memory 12 as the average value i of nXn neighboring areas including this pixel.

Therefore, the variance value calculation circuit 16 first selects a pixel group (pixel value nXn) in a predetermined area centered on the pixel of interest by the average value calculation circuit 14, and then selects a pixel group (pixel value nXn) of the pixel group (
z−E) and the pixel root mean square value are calculated, and the variance value σ is calculated.

Here, this variance value σ is obtained based on the average value Σ and the root mean square value of the neighborhood of nXn pixel groups in a predetermined area,
This is expressed as σ−z (z) 2.

Then, from the variance value σ, the comparison/arithmetic circuit 18 calculates σ1, which is predetermined by the constant setting circuit 20. σ2
, 3 of equations (1), (2), and (3) described above based on KE.
The two states K are calculated.

That is, in this comparison/calculation circuit 18, the variance value σ
are compared using two different predetermined reference variance values σ1 and σ2, and it is determined whether the variance value σ is larger than each of the reference variance values σ1 and σ2.

Specifically, σ×σ, σ≦σ≦σ2. For each K in the case of σ2 x σ, use (1) above.

It is calculated as in equations (2) and (3).

Then, the pixel value enhancement circuit 22 inputs the K, calculates z0Kx (z E), performs edge enhancement processing, and outputs 22.

As a result, the pixel value emphasizing circuit 22 can perform contour emphasizing processing in which the pixel value of interest is set larger when it is larger than the pixel average value, and smaller when it is smaller than the pixel average value.

That is, as shown in FIG. 5, when the variance value σ is determined to be σ ≦σ≦σ2, an edge enhancement process approximately proportional to the variance value σ is performed; kuσ
When it is determined that σ is 2, contour enhancement processing that is approximately inversely proportional to the variance value σ is performed.

This contour-enhanced zz is, as shown in Figure 1,
The image is outputted to an image display device such as a television monitor via the sorter 27, so that the affected area image subjected to the contour enhancement process is displayed on the television screen.

Here, the sorter 27 can select whether to perform the contour enhancement process on the entire screen or specify a predetermined range on the screen. You can switch to

Such an image state is shown in FIG. 4, with FIG. 4 (a) showing the original image and FIG. 4(b) showing the contour-enhanced image.

Then, according to the selection made by the selector 27, if the diagnostician wants to perform contour enhancement processing, and if he wants to perform contour enhancement processing for a predetermined area on the entire screen, the area inside/outside discrimination circuit 25 performs the contour enhancement processing. any area on the screen,
It is also possible to set a frame surrounding that area.

That is, in this region/inside/outside discrimination circuit 25, for example, when the switch (upper) 51 is turned on, the NAND circuit 61
The input power is 0, and one of the AND terminals receives an inverted 1 through a NOT circuit, and the other AND terminal receives a horizontal synchronizing signal (a signal with a predetermined period of 0.1) from television scanning. Ru.

Due to the operation of the NAND circuit 61, the calculation output is 1.
In this case, the counter 73 counts down and outputs a count value corresponding to the ON operation of the switch.

Of course, when the switches (lower large and small) 52 to 54 are turned on, they are similarly turned UP when the output of the NAND circuit is 1.

A DOWN count is performed and the counter 73. The count value will be output from 74.

As a result, a count value for setting a predetermined area on the screen and a frame surrounding the area is determined, each count value is added by an adder 81, and the count value before addition and the count value after addition are obtained. is input to one input terminal of comparator 8384.

The horizontal synchronizing signal count value for one horizontal scan, reset by the vertical synchronization from the counter 71, is input to the other input terminal of each of the comparators.

As a result, the comparison results are outputted from the comparators 83 and 84, and the results are inputted to the discrimination circuit 87. As shown in FIGS. 1 and 2, the discrimination circuit 87 outputs the set Setting signals for the area and frame are output.

Explanation of the settings of the contour enhancement processing area and frame Next, using FIG.
The operation of step 5 and the setting of the area and frame to be subjected to edge enhancement processing will be explained in detail.

When the diagnostician wants to perform contour enhancement processing on a predetermined area on the TV screen, he first operates a predetermined switch on the input keyboard serving as the sorter 27.Here, as shown in FIG. On the television screen A of the diagnostic imaging device, the video signal generates approximately 600 horizontal and 250 bright spots at a period of 1/60 seconds from the upper left corner to the lower right corner, and the bright spots in the upper left corner of the screen The coordinate of the point is x
-o, yo-o, the lower right is (X, Y)-(600,2
50).

Therefore, in the area inside/outside discrimination circuit 25, the count value of the counter 73 is -120, and the count value of the counter 74 is -6.
0, set the count value of the counter 71 to -100, turn on the switches 59 and 60 for setting the area and frame,
First, set the initial state.

Then, the area inside/outside discrimination circuit 25 displays a rectangular white frame B of a predetermined area approximately in the center of A on the television screen as shown in FIG.

In this initial state, the count value of the counter 73 is a
The Y coordinate of the point and the count value of the counter 74 are as shown in the figure a-c.
the counter 7 by the adder 81.
Each count value of 3.74 is added, and this results in 0 as shown in the figure.
Find the Y coordinate of the point.

Next, the diagnostician operates the upper, lower, left, right, large and small switches 51 to 58 of the switch circuit 50 to turn them ON and OFF, and specifies an area at an arbitrary position on the TV screen, that is, a desired part of the affected part image to be diagnosed. Set the area you want to perform contour enhancement processing.

This area setting can be performed, for example, by the diagnostician after setting the initial state by freely varying the size and position of the white frame that appears at the center of the screen while viewing the diagnostic image.

Specifically, for example, when the switch (upper) 51 is turned on, the counter 7 is turned on according to the frequency rate of the clock 2.
The count value of 3 is counted DOWN, and as a result, the illustrated point a and the 0 point move upward on the screen A.

That is, this is because the count value of the counter 73 approaches 0, and the count value output of the adder 81 also decreases at the same rate.

Further, when the switch (large) 53 is turned ON, the count value of the counter 73 does not change or the count value of the counter 74 does not change.
is counted up and the count value increases, and as a result, the output count value of the adder 81 also increases. As a result, the point a does not increase and therefore does not move, or the Y coordinate of the 0 point increases and the 0 point moves downward on the screen A, and the white frame changes to a vertically long frame.

On the other hand, the counter 71 counts horizontal synchronization signals, and has a count value of 0 to 25 every 1760 seconds of vertical synchronization.
The count of 0 will be repeated.

Therefore, if the count value of this counter 71 is, for example, 150 at a certain point in time, it can be determined from the comparator 8384 that the position of the television scanning line at that point is between the point a and the zero point.

In this way, the horizontal direction of the screen, which is shown in the lower part of FIG. The circuit for determining the positional relationship also performs the same operation as above.

In other words, the UP-DOWN counter 75 is
The UP-DOWN counter 76 calculates the count value of the coordinates from a to b.
Then, the adder 82 calculates the X coordinate of point b. Thereby, a horizontally long frame can be formed by increasing or decreasing the count value at point b.

Therefore, the combination of the circuit configuration for determining the positional relationship in the horizontal direction of the screen and the circuit configuration for determining the positional relationship in the vertical direction consisting of the above-mentioned switches (up and down sizes) 51 to 54, the counters and the arithmetic units, Based on the output results from each comparator, the discrimination circuit 87 determines whether the positions of the scanning lines on the television screen A are abcdd which form the area and the frame.
Determine whether it is inside or not, that is, whether it is inside or outside.

Then, in parallel with these area and frame setting operations, the contour enhancement process described above is performed, so if the scanning line position is within the abcd area in the entire screen range, the image data subjected to the contour enhancement process is output. However, if it is outside the area, unprocessed image data is output, and finally only the area within the set area of one screen can be subjected to contour enhancement processing.

As a result, when displaying a tomographic image of an organ, etc., as shown in FIG. (b) Alternatively, it is possible to designate a region and display the region A' and frame B" on which the contour enhancement process has been performed on the screen.

In other words, when both the switches 59 and 60 are ON, the setting area A' and the frame B', which have been subjected to contour enhancement processing, are displayed (
(Figure (c)), when only the switch 59 is ON, the frame B' is not displayed and the image of the setting area A' is displayed (Figure (d)).

In this embodiment, as shown in FIGS. 3 and 4, the frame B' surrounding the predetermined area A'' on which the contour enhancement process is performed is made into a rectangular shape, but the present invention is not limited to this. It is also possible to use an ellipse or any other arbitrary shape.

In addition, in this embodiment, the contour enhancement process is performed using two different reference variance values σ1. The case where σ2 is set is shown, but 1
It is also possible to set only one reference dispersion value σ1, and although the case where the image information is provided by an ultrasonic diagnostic apparatus is shown, it is not applicable only to this.

Furthermore, two different reference variance values σ1. The case where σ2 is fixed to a predetermined value has been shown, but of course the σ1. It is also possible to change σ2 arbitrarily, and the contour enhancement level can be changed in accordance with this change.

Furthermore, according to this embodiment, it is also possible to perform the contour enhancement processing in parallel and sequentially in real time using a pipeline processing method.

[Effects of the Invention] As described above, according to the image contour enhancement processing device according to the present invention, the pixel value enhancement means compares and determines the variance value with the reference variance value, and based on this, the necessary An arbitrary area and a frame surrounding the area can be set on the image display screen according to the image display, and the optimum outline enhancement process can be performed for this area.

Furthermore, since it is possible to display a frame on the screen as necessary, it is possible to easily determine whether the area is an area whose outline has been emphasized.

As a result, the diagnostician can set only the predetermined area to be observed depending on the diagnosis situation, and can obtain an image display state with appropriate contour enhancement processing, which allows for accurate observation of the affected area. This has the effect of making diagnosis easier.

[Brief explanation of the drawing]

FIG. 1 is a circuit block diagram showing an embodiment of an image contour enhancement processing device according to the present invention, FIG. 2 is an internal configuration diagram of the area inside/outside discrimination circuit shown in FIG. 1, and FIG. 4 is an explanatory diagram showing a specific area on a TV screen where contour enhancement processing is to be performed and a frame surrounding the area. FIG. FIG. 5 is an explanatory diagram showing the operation of the pixel value enhancement circuit of FIG. 1. 14 ... Average value calculation circuit 16 ... Variance value calculation circuit 18 ... Comparison / calculation circuit 20 ... Constant setting circuit 22 ... Pixel value emphasis circuit 25 ... Area inside/outside discrimination circuit 27 ... - Sorter 50...Switch circuits 51-60...Switches 61-68,89,90...NAND circuit 71
．． 72... Counters 73 to 76... UP-DOWN counters 81, 8
2...Adders 83 to 86...Comparator 87...Discrimination circuit σ...Dispersion value σ1. σ2 ・・・ Standard distributed value resistor

Claims (1)

[Claims] (1) Select a pixel group in a predetermined area centered on the pixel of interest in the image information, calculate the pixel average value of the pixel group, and calculate the variance value based on the pixel value of the pixel of interest and the pixel average value. a variance value calculation means for calculating the variance value; a comparison determination means for comparing the variance value with a predetermined reference variance value and determining whether or not the variance value is larger than the reference variance value; Based on the pixel value, if the pixel value of interest is larger than the pixel average value, the pixel value is set larger; if the pixel value is smaller than the pixel average value, the pixel value is set smaller, and a pixel value enhancement unit performs contour enhancement processing; an enhancement processing range selection means for selecting whether to perform the contour enhancement processing over the entire range on the screen or within a predetermined range; and when performing the outline enhancement processing within the predetermined range, a variable area on the screen; and a frame display selection means for selecting whether or not to display a frame surrounding the area on the screen. An image contour enhancement processing device characterized in that an emphasis region and a frame can be set, and only an image within the region is subjected to contour enhancement processing.