KR0176493B1 - Contour compensation circuit for digital image - Google Patents

Abstract

A contour correction circuit of a digital image which reads a pixel component in a diagonal direction and detects a contour, and corrects a pixel brighter than the other pixel among the two pixels detected as the contour, and corrects a dark pixel darker. It is disclosed that the comparison data read control section generates an address in the memory for reading two pixels in a diagonal direction from a memory in which luminance data for one image is recorded, and a diagonal line stored at an address generated in the comparison data read control section. A contour detector which detects a contour portion by reading two pixel data in a direction from the memory; and when two diagonally-oriented pixels read from the memory are determined as the boundary of the contour in the contour detector, the darker of the two pixels read from the memory. Pixels with luminance components The darker and brighter pixels are composed of a contour correction unit for brighter correction and recording in memory, making the contours of an unclear digital image more vivid using a simple circuit configuration and human visual characteristics. In addition, the vertical component and the horizontal component of the portion to be compared can be compared at the same time.

Description

Contour Correction Circuit of Digital Image

1 is an exemplary diagram for performing a conventional outline correction.

2 is a block diagram showing a contour correction circuit of a digital image according to the present invention.

3 is a detailed block diagram of the contour detector of FIG. 2;

4 is a detailed block diagram of the contour correction unit of FIG. 2;

5 is an exemplary view showing an example of reading diagonal data among data of one image according to the present invention.

6 is an exemplary view showing an example in which the contour according to the present invention is corrected.

7 is an exemplary view showing an example of reading data when the last line is odd among the data of one image according to the present invention.

* Explanation of symbols for main parts of the drawings

100,500: memory 200: comparison data read control

300: contour detection unit 301: arithmetic unit

303: contour limit comparison unit 400: contour correction unit

401: Latitude determining unit 403: Luminance correction unit

405: Multiplexer

The present invention relates to a contour correction circuit of a digital image, and more particularly, to detect a contour using a pixel component in a diagonal direction, and to display a pixel brighter than another pixel among two pixels detected as a contour, with a brighter component. And a darker pixel to be darker, thereby correcting the outline of the digital image.

1 shows an embodiment of correcting a conventional contour, and corrects the contour as g (x, y) = T [f (x, y)].

Where g (x, y) is the contour-corrected image, T is the operator with gray-level conversion, and f (x, y) is the original image.

That is, referring to FIG. 1, one mask is formed based on several groups around the (x, y) point.

The contour correction is performed by obtaining values calculated while applying the mask group (eg, 3 × 3) to the entire screen.

In this case, since the obtained values are digital image filtering, the association becomes complicated depending on the size of the mask group, and the time becomes longer.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to detect two pixels of a diagonal component of an image, and if the detected pixels are determined as contour portions, one of the two pixels is brighter than the other pixel. By correcting with pixels of brighter components and darker pixels with darker components, it is possible to provide a contour correction circuit of a digital image that more clearly shows a contour boundary with a simple circuit configuration.

Another object of the present invention is to provide an outline correction circuit of a digital image that more clearly shows the outline portion of an unclear digital image using human visual characteristics.

A feature of the contour correction circuit of a digital image according to the present invention for achieving the above object is that two pixels in a diagonal direction are inserted into the memory to lead two pixels in a diagonal direction from a memory in which luminance data of one image is recorded. Comparison data read control means for generating an address of data, contour detection means for detecting a contour portion by reading two pixel data in a diagonal direction stored at an address generated by said comparison data read control means from a memory, and read in said memory; When the two diagonally aligned pixels are determined as the boundary of the contour by the contour detecting means, the pixel having the dark luminance component of the two pixels read from the memory is darker and the pixel having the bright luminance component is brighter. As a contour correction means to record on In the point that.

Hereinafter, a preferred embodiment of the outline correction circuit of a digital image according to the present invention will be described in detail with reference to the accompanying drawings.

2 is a block diagram of a contour correction circuit of a digital image according to the present invention.

Referring to FIG. 2, in the memory 100 in which luminance data of one image is recorded, diagonal pixel data is read in the memory 100 in order to read two pixels in a diagonal direction when reading the data recorded in the memory 100. The comparison data read control unit 200 providing an address is connected.

In addition, the memory 100 is connected to the contour detection unit 300 for reading a contour portion by reading two pixel data in a diagonal direction stored at an address provided from the comparison data read control unit 200.

If it is determined that the two pixels in the diagonal direction read by the contour detector 300 are contour parts, the contour detector 300 corrects the pixels having dark luminance components among the two pixels read from the memory 100 to be darker. The pixel having a bright luminance component is connected to the contour correction unit 400 for brighter correction.

3 is a detailed block diagram of the contour detector 300.

Referring to FIG. 3, the two diagonal pixels read by comparing a predetermined value with a value calculated by the calculation unit 301 which subtracts the luminance values of two diagonal pixels read from the memory 100 are outlined. The contour limit comparison unit 303 for detecting whether or not a part is connected is connected.

In this case, the predetermined value compared by the contour limit comparison unit 303 may be obtained through an experiment or the like as a reference value of the boundary portion that can be felt by the human eye.

4 is a detailed block diagram of the outline correction unit 400.

As shown in FIG. 4, in the contour limit comparison unit 303 of the contour detection unit 300, luminance data in a diagonal direction to which the detection signal output from the contour limit comparison unit 303 is read is determined as the contour portion. If it is a signal indicating that the signal is displayed, the brightness determining unit 401 separating the dark pixels and the bright pixels by comparing the degree of contrast of the two brightness data in the diagonal direction read from the memory 100 is connected.

In addition, the luminance determiner 401 has a darker pixel and a brighter pixel of the diagonal luminance data read out from the memory 100 due to the contrast signal output from the luminance determiner 401. The luminance correction unit 403 for correction is connected.

In addition, an input terminal of the multiplexer 405 is connected to the luminance corrector 403 and the memory 100, and a selection terminal s of the multiplexer 405 is connected to an output terminal of the contour detector 300.

According to the present invention configured as described above, since each luminance component of the digital image is represented by a digital value so that the luminance component of the pixel can be known, the contour portion is detected and corrected using digital data of the luminance component of the image.

That is, the comparison data read control unit 200 provides an address of the pixel data in the diagonal direction to the memory 100 to read two pixels in the diagonal direction from the memory 100 in which luminance data of one image is recorded.

In this case, two pixel data in a diagonal direction are read as shown in FIG. 5 according to an address provided from the comparison data read control unit 200.

Here, the order of the pixels to be read is in the order of the diagonal direction as follows.

Comparative Pixel 1: Pixel 1 (X1, Y1) and Pixel 2 (X2, Y2)

Comparative Pixel 2: Pixel 3 (X2, Y1) and Pixel 4 (X3, Y2)

Comparative Pixel 3: Pixel 5 (X3, Y1) and Pixel 6 (X3, Y2)

:

:

In this case, the pixel 1 and the pixel 2 are pixel components in the diagonal direction, and the vertical and horizontal components are simultaneously compared because the pixel components in the diagonal direction are compared without comparing the adjacent pixels in the vertical direction and the adjacent pixel components in the horizontal direction. You can get the effect.

Meanwhile, two pieces of luminance data (eg, pixel 1 and pixel 2) in the diagonal direction read from the memory 100 by the address generated by the comparison data read control unit 200 are transferred to the calculation unit 301 of the contour detection unit 300. It is input and subtraction is performed.

In addition, the value calculated by the calculating unit 301 is compared with a predetermined value by the contour limit comparison unit 303.

In this case, the predetermined value may be obtained through experiments as a reference value of the boundary portion that can be felt by the human eye, and two luminance data (eg, pixel 1 and pixel 2) in the diagonal direction read from the memory 100 are outlined. Is set to determine if it is part.

Therefore, the contour limit comparison unit 303 determines that the contour between two luminance data (eg, pixel 1 and pixel 2) read in the memory 100 when the calculation value calculated by the operation unit 301 is higher than a predetermined value. It is determined that the interface and the detection signal is generated by the contour correction unit 400.

When the detection signal is input from the outline detector 300 to the brightness determiner 401 of the outline corrector 400, that is, two pieces of luminance data (eg, pixel 1 and pixel 2) in a diagonal direction read from the memory 100. When is determined as the boundary surface of the contour, the luminance determiner 401 analyzes two luminance components (eg, pixel 1 and pixel 2) in the diagonal direction read from the memory 100. Then, the degree of contrast between the analyzed luminance data is compared and separated into a dark pixel and a bright pixel, and output to the brightness correction unit 403 as a contrast separation signal.

The luminance corrector 403 further controls a dark pixel of two diagonal luminance data (eg, pixel 1 and pixel 2) read from the memory 100 by the contrast signal output from the luminance determiner 401. The darker the correction, the brighter the pixel.

That is, when it is determined that the two luminance data read from the memory 100 are the boundary of the contour as shown in FIG. 6 (a), the luminance correction unit 403 further displays dark pixels among the two luminance data as shown in FIG. The darker the correction, the brighter the pixel.

The detection signal of the contour detector 300 is also input to the selection terminal s of the multiplexer 405.

Therefore, when the detection signal is input to the selection terminal of the multiplexer 405, that is, when the two luminance data (eg, pixel 1 and pixel 2) in the diagonal direction read from the memory 100 are determined as the boundary of the contour, the multiplexer 405. ) Selects the luminance data corrected by the luminance corrector 403 and writes them to the memory 100.

However, if the detection signal is not input to the selection terminal of the multiplexer 405, that is, if it is determined that two luminance data (eg, pixel 1 and pixel 2) in the diagonal direction read from the memory 100 are not the boundary of the outline, The multiplexer 405 directly selects two luminance data (eg, pixel 1 and pixel 2) read from the memory 100 and writes the same to the memory 100.

On the other hand, in the present invention, when the last line m of the image becomes odd, Ym is controlled by the comparison data read control unit 200, that is, by the address generated by the comparison data read control unit 200 as shown in FIG. Two luminance data are read in diagonal direction with -2 line and Ym-1 line as a pair, and if the luminance data is the boundary of contour, luminance correction is performed, and again, two luminance data is paired with Ym-1 line and Ym line as a pair. If the two luminance data are the boundary of the contour, the luminance is corrected.

That is, lead the Ym-1 line twice.

Thus, it is possible to correct the outline of the last horizontal component in an image having odd horizontal lines.

As described above, according to the contour correction circuit of the digital image according to the present invention, the contour portion of the unclear digital image is more clearly represented by using human visual characteristics, and two pixels of diagonal components of one image are detected. When the detected pixel is determined as the contour part, the brighter pixel than the other one of the two pixels is corrected with the brighter component and the darker pixel is darker to correct the contour boundary with a simple circuit configuration. In addition, there is an effect of comparing the vertical and horizontal components of the portion to be compared at the same time.

Claims (4)

Comparison data read control means for generating an address of two pixel data in a diagonal direction in the memory to read two pixels in a diagonal direction from a memory in which luminance data of one image is recorded, and an address generated in the comparison data read means Contour detection means for detecting a contour portion by reading two pixel data in a diagonal direction stored in the memory; and when the two diagonal pixels read in the memory are determined as the boundary of the contour in the contour detection means, A contour correction circuit of a digital image, comprising: contour correction means for correcting a darker pixel of two pixels, and brighter a pixel having a brighter luminance component and writing it to a memory. 2. The contour detection unit of claim 1, wherein the contour detection unit comprises: an operation unit which performs subtraction of luminance values of two pixels in a diagonal direction read from the memory, and compares an operation value calculated by the operation unit with a predetermined value, A contour correction circuit of a digital image, comprising an outline threshold comparison unit for discriminating two pixels in a diagonal direction read from a memory as a boundary of an outline, if it is determined to be large. The method of claim 1, wherein the contour correction means compares the degree of contrast between the two luminance data in the diagonal direction read from the memory when the two luminance data in the diagonal direction read from the contour detection means are determined as the boundary of the contour. A luminance determination unit for separating dark and bright pixels, a luminance correction unit for correcting darker pixels and brighter brighter pixels among the two luminance data diagonally read from the memory by the output of the luminance determining unit; If the two luminance data in the diagonal direction read by the contour detecting means are determined as the boundary of the contour, the output of the luminance correction unit is selected. An outline correction circuit for a digital image, comprising a selection unit for directly selecting. 4. The outline correction circuit of claim 3, wherein the selector comprises a multiplexer.