KR101193460B1 - Method of matrix filtering within digital image processing apparatus - Google Patents

Abstract

The present invention is a matrix filtering method in which a digital image processing apparatus performs matrix filtering using matrix data on each pixel data of the image data in order to change the sharpness of the image data. Here, for each pixel data to be used, matrix data having a skip structure that does not include adjacent pixel data is used.

Description

Method of matrix filtering within digital image processing apparatus

1 is a block diagram of a digital camera as a digital image processing apparatus for performing a matrix filtering method according to the present invention.

2 is a flowchart illustrating an algorithm in which the digital signal processor of FIG. 1 performs matrix filtering.

FIG. 3 is a diagram for describing a structure of matrix data used in step S3 of FIG. 2.

4 is a diagram illustrating an example of a frame of image data input to the digital signal processor of FIG. 1.

FIG. 5 is a diagram illustrating that step S3 of FIG. 2 is performed on pixel data having a horizontal-vertical coordinate of (7,6) in the frame of FIG. 4.

FIG. 6 is a diagram illustrating that step S3 of FIG. 2 is performed on pixel data having a horizontal-vertical coordinate of (9,6) in the frame of FIG. 4.

FIG. 7 is a diagram illustrating that step S3 of FIG. 2 is performed on pixel data having a horizontal-vertical coordinate of (11,6) in the frame of FIG. 4.

FIG. 8 is a diagram illustrating that step S3 of FIG. 2 is performed on pixel data having a horizontal-vertical coordinate of (9,8) in the frame of FIG. 4.

FIG. 9 is a diagram illustrating that step S3 of FIG. 2 is performed on pixel data having a horizontal-vertical coordinate of (11,8) in the frame of FIG. 4.

 <Explanation of symbols for the main parts of the drawings>

1 ... digital camera, 12 ... flash,

19 flash-light sensor, 21 external interface,

MIC ... microphone, SP ... speaker,
35 ... color LCD panel, OPS ... optical system,

OEC ... photoelectric converter, M _Z ... zoom motor,

M _F ... focus motor, M _A ... aperture motor,

501 ... CDS-ADC, 502 ... timing circuit,
503 ... real time clock, 504 ... DRAM,
505 ... EEPROM, 506 ... memory card interface,
507 ... digital signal processor, 508 ... RS232C interface,
509 ... video filter, 21a ... USB connection,
21b ... RS232C connection, 21c ... video output,
510 ... drive section, 511 ... flash controller,
512 ... microcontroller, INP ... user input,
LAMP ... light emitting unit, 513 ... audio processor,
514 LCD drive.

The present invention relates to a matrix filtering method, and more particularly, to a matrix filtering method for performing matrix filtering on each pixel data of image data in order to change the sharpness of the image data in a digital image processing apparatus. It is about.

Digital image processing apparatus For example, in order to change the sharpness of image data according to a user's selection, the digital camera performs matrix filtering on matrix data of each pixel data of the image data. When matrix filtering is performed as described above, pixel data to be filtered is updated by matrix filtering. The matrix data includes pixel data to be matrix filtered and data surrounding the matrix data.

For example, in order to reduce the sharpness of the image data according to the user's selection, the pixel data to be filtered is updated as an average value of the pixel data to be filtered and the data around it.

 In the matrix filtering as described above, the larger the matrix data, that is, the larger the area occupied by the pixels of the matrix data, the larger the filtering effect but the lower the processing speed.

For example, the use of 5 X 5 matrix data is more effective than the case of using 3 X 3 matrix data, but the processing speed is lower. Similarly, the use of 7 × 7 matrix data is more effective than the case of using 5 × 5 matrix data, but the processing speed is lower.

An object of the present invention is to provide an efficient matrix filtering method capable of increasing the processing speed while increasing the filtering effect in a digital image processing apparatus.

The present invention for achieving the above object is a matrix filtering method for performing matrix filtering on each pixel data of the image data using matrix data in order to change the sharpness of the image data in the digital image processing apparatus. Here, for each pixel data to be used, matrix data having a skip structure that does not include adjacent pixel data is used.

According to the matrix filtering method of the present invention, as the matrix data of the skip structure is used, the area occupied by the pixels of the matrix data is widened while the amount of the matrix data is reduced. Accordingly, the processing speed can be high while the filtering effect is large.

Hereinafter, preferred embodiments according to the present invention will be described in detail.

1 shows a configuration of a digital camera 1 as a digital image processing apparatus that performs a matrix filtering method according to the present invention. Referring to Figure 1, the overall configuration and operation of the digital camera 1 of Figure 1 will be described.

The optical system OPS including the lens unit and the filter unit optically processes light from a subject.

The lens portion of the optical system OPS includes a zoom lens, a focus lens, and a compensation lens.

When the user presses the wide angle zoom button or the telephoto zoom button included in the user input unit INP, a corresponding signal is input to the microcontroller 512. Accordingly, as the microcontroller 512 controls the driving unit 510, the zoom motor M _Z is driven to move the zoom lens.

Meanwhile, in the auto focus mode, the focus motor M _F is driven by the main controller embedded in the digital signal processor 507 controlling the driving unit 510 through the microcontroller 512.

The compensating lens of the lens unit of the optical system OPS is not driven separately because it serves to compensate the overall refractive index. Reference symbol M _A denotes a motor for driving an aperture.

In the filter section of the optical system (OPS), an optical low pass filter removes optical noise of a high frequency component. Infra-red cut filter blocks the infrared component of incident light.

A photoelectric conversion unit (OEC) formed of a charge coupled device (CCD) or a CMOS-image sensor (CIS) converts light from an optical system OPS into electrical signals.

The digital signal processor 507 controls the timing circuit 502 to control the operations of the photoelectric converter OEC and the analog-digital converter 501. The CDS-ADC (Correlation Double Sampler and Analog-to-Digital Converter) element 501 removes the high frequency noise of the analog image signals from the photoelectric converter (OEC) and adjusts the amplitude, and then converts the analog image signals into a digital image. The signals are converted into video data.

The real-time clock 503 provides time information to the digital signal processor 507.

The digital signal processor 507 processes the image data from the CDS-ADC element 501 according to the image mode selected by the user. For example, in order to change the sharpness of the image data according to a user's selection, matrix filtering is performed on each of the pixel data of the image data using matrix data. This matrix filtering algorithm will be described in detail with reference to FIGS.

The light emitting unit LAMP including various lamps is driven by the microcontroller 512 according to control signals from the digital signal processor 507 including the main controller.

The digital image data from the digital signal processor 507 is temporarily stored in the DRAM (Dynamic Random Access Memory) 504. The EEPROM (Electrically Erasable and Programmable Read Only Memory) 505 stores algorithms and setting data necessary for the operation of the digital signal processor 507. In the memory card interface 506, a user's memory card as a recording medium is detached.

The digital image data from the digital signal processor 507 is input to the LCD driver 514, whereby the image is displayed on the color LCD panel 35.

On the other hand, the digital image data from the digital signal processor 507 can be transmitted by serial communication via the USB (Universal Serial Bus) connection 21a or the RS232C interface 508 and its connection 21b, and the video filter ( 509 and the video output unit 21c can be transmitted as a video signal.

The audio processor 513 outputs the audio signal from the microphone MIC to the digital signal processor 507 or the speaker SP and outputs the audio signal from the digital signal processor 507 to the speaker SP.

On the other hand, the microcontroller 512 drives the flash 12 by controlling the operation of the flash controller 511 according to the signal from the flash-light amount sensor 19.

2 illustrates an algorithm in which the digital signal processor 507 of FIG. 1 performs matrix filtering. FIG. 3 is a diagram for describing a structure of matrix data used in step S3 of FIG. 2. 4 illustrates an example of a frame DFR of image data input to the digital signal processor 507 of FIG. 1. FIG. 5 shows that step S3 of FIG. 2 is performed on pixel data having a horizontal-vertical coordinate of (7,6) in the frame DFR of FIG. 4. FIG. 6 shows that step S3 of FIG. 2 is performed on pixel data having a horizontal-vertical coordinate of (9,6) in the frame DFR of FIG. 4. FIG. 7 shows that step S3 of FIG. 2 is performed on pixel data having a horizontal-vertical coordinate of (11,6) in the frame DFR of FIG. 4. FIG. 8 shows that step S3 of FIG. 2 is performed on pixel data having a horizontal-vertical coordinate of (9,8) in the frame DFR of FIG. 4. FIG. 9 shows that step S3 of FIG. 2 is performed on pixel data having a horizontal-vertical coordinate of (11,8) in the frame DFR of FIG. 4.

The algorithm of FIG. 2 will be described with reference to FIGS. 2 to 9.

When the image data is input, the digital signal processor 507 sets the x and y coordinates (x, y) of the pixel data DP (x, y) to be filtered to (1,1) (steps S1 and S2).

Next, the digital signal processor 507 performs matrix filtering on the target pixel data DP (x, y) by using the matrix data of the skip structure that does not include adjacent pixel data for each pixel data to be used. (Step S3).

In the above step S3, the conventional matrix data (M _OLD of FIG. 3) includes pixel data to be matrix filtered, for example, DP (2, 2) and data around it, and each pixel data to be used is different from each other. It has an adjacent structure. However, the matrix data (M _NEW of FIG. 3) according to the present invention includes pixel data to be matrix filtered, for example, DP (3,3) and data around it, but adjacent pixels for each pixel data to be used. It has a skip structure that does not contain any data. Accordingly, the area occupied by the pixels of the matrix data is widened while the amount of the matrix data is reduced. Accordingly, the processing speed can be high while the filtering effect is large.

For example, in matrix filtering in the case of lowering the sharpness, the pixel data DP (x, y) is changed to the new pixel data DP _N (x, y) by the following equation (1).

Applying Equation 1 to FIG. 3, the pixel data DP (3, 3) is changed to the new pixel data DP _N (3, 3) by Equation 2 below.

For example, when the pixel data to be filtered in the unit frame (DFR of FIG. 4) is DP (7,6), which is data of (7,6) coordinates, the matrix data to be used for filtering is (5,4), ( 7,4), (9,4), (5,6), (7,6), (9,6), (5,8), (7,8), and pixels of (9,8) coordinates Data (see FIG. 5). In this case, a filtering effect similar to the case of using 5 × 5 matrix data while using 3 × 3 matrix data can be obtained.

Next, when the digital signal processor 507 obtains a new value of the target pixel data DP (x, y) by performing step S3, for example, when the average value of the matrix data is obtained when the sharpness is lowered, The value of the target pixel data DP (x, y) is updated with this new value (step S4).

Next, the digital signal processor 507, if the currently set x coordinate is less than its final value (x _END ) (step S5), the filtering for all the pixels of the current row (low) is not completed Therefore, the currently set x coordinate is increased by 2 (step S6). As a result, the pixel data to be filtered is set to the pixel after skipping one pixel in the horizontal direction (x-axis direction).

For example, when the latest target pixel data is DP (7,6) (see FIG. 5), the next target pixel data is DP (9,6) (see FIG. 6). In addition, when the latest target pixel data is DP (9, 6) (see Fig. 6), the next target pixel data is DP (11, 6) (see Fig. 7). Similarly, when the recent target pixel data is DP (9,8) (see FIG. 8), the next target pixel data is DP (11,8) (see FIG. 9).

The filtering steps S3 to S5 are performed on the newly set target pixel data.

Of course, the x coordinate currently set in step S6 may be increased by one. In this case, since the pixel data to be filtered is set to adjacent pixels in the horizontal direction (x-axis direction), the filtering effect can be increased but the processing speed is lowered.

On the other hand, when the currently set x coordinate is equal to or greater than its final value (x _END ) (step S5), the digital signal processor 507 has completed filtering on all pixels of the current row, and thus, the current setting. The value of the made x coordinate is set to '1' (step S7). Next, the digital signal processor 507 compares the currently set y coordinate with its final value y _END (step S8).

In step S8, if the currently set y coordinate is less than its final value (y _END ), since the filtering of the last row is not performed, the digital signal processor 507 sets the currently set y coordinate by two. Increase (step S9). Accordingly, the pixel data to be filtered is set as the first pixel of the next row after skipping one row in the vertical direction (y-axis direction). For example, when the latest target pixel data is DP (17,8), the next target pixel data is not DP (1,9) but DP (1,10). Next, the digital signal processor 507 repeatedly performs the above step S3 and the following steps.

Of course, the y coordinate currently set in step S9 may be increased by one. In this case, since the data to be filtered increases, the filtering effect can be increased, but the processing speed is lowered.

On the other hand, if the currently set y coordinate is equal to or greater than the final value y _END (step S8), the digital signal processor 507 has filtered the pixel data of all filtering targets of the unit frame DFR. Then, filtering is terminated after correcting the pixel data not updated due to the skipping in the horizontal direction (x-axis direction) and vertical direction (y-axis direction), respectively (step S10).

Here, the pixel data that is not updated, that is, the pixel data that is not selected, is corrected by the update data of the pixel data that has been selected. For example, the unselected pixel data DPRs 10 and 8 are corrected by the update data DPs 9 and 8 and DPs 11 and 8 around them (see Figs. 8 and 9).

As described above, according to the matrix filtering method according to the present invention, as the matrix data of the skip structure is used, the area occupied by the pixels of the matrix data is widened while the amount of the matrix data is reduced. Accordingly, the processing speed can be high while the filtering effect is large.

The present invention is not limited to the above embodiments, but may be modified and improved by those skilled in the art within the spirit and scope of the invention as defined in the claims.

Claims (8)

In the matrix filtering method for each pixel data, Selecting pixel data spaced apart by at least one pixel data in horizontal, vertical and diagonal directions with respect to the pixel data to be used; Averaging matrix data including the pixel data to be used and the selected pixel data; And Updating the pixel data to be used with the averaged pixel data. delete delete delete The pixel data of claim 1, wherein the pixel data to be used next is: Matrix data spaced apart from the pixel data to be used by at least one pixel data in a vertical or horizontal direction. delete 6. The method of claim 5, A matrix filtering method in which unused pixel data is corrected after all pixel data is updated. The method of claim 7, wherein And the unused pixel data is corrected by the update data of the used pixel data.

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