KR101923971B1 - Imaging device and image processing method - Google Patents

Abstract

The present invention provides an imaging apparatus capable of efficiently compressing and encoding a JPEG image by dividing an image subjected to image processing without passing through an external memory into a plurality of blocks and performing JPEG compression encoding, and also capable of generating a natural compressed image. An image pickup apparatus according to the present invention includes an image processing unit for generating image data from light input to an image pickup device, an encoding unit for encoding the image data to generate encoded image data, and a storage unit for storing the encoded image data do.

Description

[0001] IMAGING DEVICE AND IMAGE PROCESSING METHOD [0002]

The present invention relates to an image pickup apparatus and an image processing method.

The compression encoding of an image by the JPEG method processes one screen as one unit. On the other hand, in an LSI (Large Scale Integration) installed in a digital still camera or the like, in order to save the capacity of the line memory, one image is divided into a plurality of blocks in the vertical direction and processed.

Therefore, in order to process all one image and make it possible to perform JPEG compression, it is necessary to end the processing of all the blocks and to record the processing result in an external memory such as SDRAM and combine the blocks and the processing result have. A JPEG compression encoder for JPEG compression reads an image composed in an external memory and performs compression encoding. For this purpose, JPEG compression in a digital still camera always includes a procedure of recording an image in an external memory such as one SDRAM and reading it from the external memory.

The speed performance of the conventional digital still camera is determined by the speed performance of the image pickup device. In addition, the speed performance of a digital still camera required only 3 to 7 frames of continuous shooting performance per second. However, in recent years, the performance of an image pickup device has progressed, and a resolution of 12 million pixels to 20 million pixels or more has been used. Also, in recent years, the speed performance of 10 to 15 frames per second is required for the continuous shooting performance, and the processing performance required for the digital still camera is significantly higher than that of the conventional camera.

As a result, the digital still camera reads the image from the external memory or repeatedly writes the image in the external memory for JPEG compression coding of the image. In addition, the power consumption increases and the number of external memories mounted increases in order to solve the decrease in speed due to the increase of reading and writing, and the price of the digital still camera increases as the number of external memories increases. Therefore, there is an increasing need to perform JPEG compression coding of an image without making it possible to read and write data to an external memory.

On the other hand, JPEG compression coding is based on DCT, and can be encoded only in units of 8 pixels vertically. Generally, in the case where the lowermost portion does not reach 8 pixels, a method of copying the last line or coding the lowermost portion by inserting a black line is used. However, if the last line is copied or the black line is inserted to encode the lowermost portion, there is a problem that an image corresponding to the lowermost portion becomes an unnatural image.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and it is an object of the present invention to provide an image processing apparatus and a method thereof, which can divide an image after image processing into a plurality of blocks, An image pickup apparatus and an image processing method capable of JPEG compression encoding and capable of generating a natural compressed image.

According to an aspect of the present invention, there is provided an image pickup apparatus including an image processing section for generating image data from light input to an image pickup element, an encoding section for encoding the image data to generate encoded image data, And a storage unit for storing the encoded image data, wherein the image processing unit divides the image data into a plurality of blocks in the horizontal direction and supplies the divided data to the encoding unit, And a filter control unit for controlling a filter process of the filter unit, wherein the filter control unit acquires information on the number of vertical pixels of the image data, If the number of pixels is not divided by the number of vertical pixels of a predetermined coding unit, The control unit controls the filter unit to copy the data of the last row of the image data until the data is copied and add the data of the last row of the image data to the image data.

According to the above configuration, the predetermined filter processing performed by the filter unit is a filter process for making the number of pixels of input data coincide with the number of pixels of output data. The image processing unit includes at least two filter units, the at least two filter units are cascade-connected, and the filter unit at the rearmost end of the at least two filter units has a number of pixels of input data and a number of pixels of output data And performs a filter process for matching them. The image processing unit acquires the number of vertical pixels of the coded image data, and when the number of vertical pixels of the coded image data is not divided by the number of vertical pixels, which is a coding unit, And generates the encoded image data. As a result, the digital still camera according to the present invention can efficiently JPEG compress and encode the image after image processing without dividing it into a plurality of blocks without going through an external memory, and can generate a natural compressed image.

An image processing method according to an embodiment of the present invention includes an image processing step of generating image data from an incident light to an image pickup element, a coding step of coding the image data to generate encoded image data, Wherein in the image processing step, if the image data is divided into a plurality of blocks in a horizontal direction, the image data is encoded in the encoding step, and the image processing step comprises: At least one filter process for performing a predetermined filter process on the image data, and a filter control process for controlling the filter process in the filter process, wherein the filter control process comprises: Acquires the number of vertical pixels of the image data, A step of controlling the filter processing in the filter processing so that data of the last row of the image data is copied and added to the image data until the image data is divided by the number of vertical pixels divided by the number of vertical pixels .

As described above, according to the present invention, there is provided an image pickup apparatus and an image processing method capable of efficiently compressing a JPEG image by dividing an image subjected to image processing without passing through an external memory into a plurality of blocks and performing JPEG compression encoding, Method can be provided.

FIG. 1 is a diagram showing a JPEG compression coding of a digital still camera according to the prior art,
2 is a diagram for explaining a case where differential coding between blocks can not be used according to the prior art,
3 is a diagram showing image data according to the prior art,
4 is a block diagram illustrating the configuration of a digital still camera according to an exemplary embodiment of the present invention.
5 is a block diagram showing the configuration of a developing unit included in a digital still camera according to an embodiment of the present invention;
Fig. 6 is a diagram showing a normal filter process for removing ring pixels, Fig.
FIG. 7 is a view illustrating filter processing by the first to third filter units of the developing unit included in the digital still camera according to the embodiment of the present invention; FIG.
8 is a flowchart showing an operation of a digital still camera according to an embodiment of the present invention;
9 is a view showing a filter process by the first to third filter units of the developing unit included in the digital still camera according to the embodiment of the present invention, and
10 is a block diagram illustrating the configuration of a digital still camera including a developing unit according to another embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the present specification and drawings, elements having substantially the same functional configuration are denoted by the same reference numerals, and redundant description will be omitted.

1. Prior art and its problems

Before describing the preferred embodiments of the present invention in detail, problems of the prior art and the prior art will be described.

1 is a diagram showing JPEG compression coding of a digital still camera according to the related art. 1 is a diagram showing the configuration of the invention described in Japanese Patent Application Laid-Open No. 2007-267349 (hereinafter referred to as "patent citation").

The above cited patent describes an invention in which one image is vertically divided and an RST marker code is added to each of a plurality of vertically divided blocks in order to reduce access to the external memory at the time of JPEG compression coding have.

The JPEG compression coding in the conventional technique as described above is not necessarily performed on one entire image, and a method of coding a part of the image by dividing the RST marker code into RST marker codes is also applicable. In FIG. 1, one picture is divided into four blocks (tile 0, tile 1, tile 2, and tile 3), and RST marker code is added to the rightmost MCU line of each block to compress-encode. As described above, when dividing one picture into a plurality of blocks in the conventional art, an RST marker code is attached to the end of the MCU line included in each of the blocks, and is encoded.

However, if the data is coded as described above, the data storage direction becomes block unit, and the storage direction does not become 'tile 0 -> tile 1 -> tile 2 -> tile 3'. Therefore, in order to preserve the encoded image data, the encoded data is referred to as the MCU line of the top row of the tile 0 -> the MCU line of the top row of the tile 1 -> ... 'And so on.

Since JPEG coding uses variable length coding, the code amount per pixel or per MCU is not constant, nor is it in units of bytes. However, since the RST marker code must be at the boundary of bytes, each of the MCU columns is in units of bytes, and handling in the external memory is thereby simplified.

However, the method of adding and compressing the RST marker code described in the cited patent has the following problems.

First, if the RST marker code is added and compressed, the encoding efficiency is lowered. In the JPEG compression coding in the divided image processing system according to the cited patent, coding is performed by taking a difference on the basis of the block information on the left side of the JPEG and performing DC prediction using the difference. In the case of dividing an image into a plurality of blocks and dividing the image into RST marker codes, since the difference is reset in units of blocks, the configuration can be simple. However, there is a need to add RST marker code codes thereto and differential coding Coding efficiency is lowered because it can not be used.

2 is a diagram for explaining a case where differential coding between blocks can not be used according to the related art. As shown in Fig. 2, in the same block, DC prediction can be performed between MCUs to perform coding. However, if the block is exceeded, the differential encoding can not be used, and the coding efficiency at the portion beyond this block (tile 0 -> tile 1) is lowered.

Next, there is a limitation on the image size in the compression in which the RST marker code is added. The image size between the RST marker codes needs to be constant. Normally, a digital still camera JPEG performs processing in units of horizontal 16 pixels with luminance components, and therefore, each block must be in units of 16 pixels. For example, in the case of a configuration in which four blocks are divided into vertical lengths, the image size can be changed only in units of 64 pixels.

Normally, the size of a block is reduced to 256 pixels horizontally or 512 pixels wide, while the entire image is enlarged to 5000 to 8000 pixels or the like. For this reason, for example, if the image is divided and processed into 32 blocks, the image size can be changed only in units of 256 pixels.

However, as described above, there are not many suitable image pickup devices, and a portion that does not divide must insert black on the right side of the image. FIG. 3 is a diagram showing image data according to the related art, and shows an image in which it is necessary to insert black on the right side according to the related art. The size of the image data 310 shown in Fig. 3 is 7952 pixels in width, and the width of each of the blocks is 256 pixels. Accordingly, the rightmost block 311 of the image data 310 shown in Fig. 3 is only image data 321 having a width of 16 pixels, which is actual image data. Accordingly, black data is inserted in the image data 322 having the remaining 240 pixels for processing as a block.

Therefore, in the present invention, when image data obtained by performing image processing without passing through an external memory is divided into a plurality of blocks and subjected to JPEG compression coding, the image size of a plurality of blocks is not limited without lowering the coding efficiency, And an image pickup apparatus which can easily combine image data even after compression is performed.

2. Embodiments of the Invention

[Example of function configuration of digital still camera]

First, the configuration of a digital still camera according to an embodiment of the present invention will be described. 4 is a block diagram illustrating the configuration of a digital still camera according to an exemplary embodiment of the present invention. 4, the digital still camera 100 includes a camera unit 102, a CPU 104, a ROM 105, a multiplexer (MUX) 106, a development unit 110, an image compression unit 112, Distortion correction processor 113, a memory card 114, an LCD 116, an SDRAM I / F 118, and an SDRAM 120, as shown in FIG.

Although not shown in FIG. 4, the camera unit 102 may be composed of a zoom lens, a focus lens, an imaging element provided with a color filter arranged in a Bayer array, etc., and photoelectrically converts light from the object into an image pickup element, And outputs RGB image data of the array. Here, the image pickup element may be implemented as a CCD image sensor or a CMOS image sensor. The camera unit 102 generates RGB image data in Bayer arrangement. The camera unit 102 transfers the generated RGB image data to the SDRAM 120 via the SDRAM I / F 118 or directly to the multiplexer 106. [ Hereinafter, for convenience of explanation, the RGB image data of the Bayer array outputted from the camera unit 102 will be referred to as 'data'.

The CPU 104 controls the operation of each of the components included in the digital still camera 100. The ROM 105 stores various programs and setting information used for controlling the operation of the digital still camera 100. The multiplexer 106 receives the data generated and output by the camera unit 102 and the image data stored in the SDRAM 120. The multiplexer 106 transmits the data or image data to the developing section 110. [

The developing unit 110 generates image data using data generated by the camera unit 102, that is, light input to the image pickup device. The image data is composed of YCbCr information including a luminance signal and a color difference signal, and the developing section 110 develops the data to generate the image data. The image data generated by the developing unit 110 is transferred to the image compressing unit 112.

The image compressing section 112 performs predetermined image compression processing on the image data generated by the developing section 110. [ The image compression section 112 compresses the image data by JPEG as predetermined image compression processing on the image data. The image data compressed by the image compression unit 112 under the control of the CPU 104, that is, the coded image data, is transferred to the SDRAM 120 through the SDRAM I /

The distortion correction processor 113 controls the supply of the clock to the SDRAM 120 to suppress the power consumption and at the same time corrects the distortion of the encoded image data stored in the SDRAM 120. [ The distortion of the encoded image data stored in the SDRAM 120 can be corrected by the distortion correction processing unit 113 as described above.

The memory card 114 stores encoded image data compressed by the image compression unit 112 and stored in the SDRAM 120. [ The coded image data can be recorded in the memory card 114 under the control of the CPU 104. [

The LCD 116 displays various setting screens of the digital still camera 100. The LCD 116 also displays the data generated by the camera unit 102 in real time (for example, in live view) or displays the encoded image stored in the memory card 114 Data can be displayed. In this embodiment, the LCD 116 is used to display various data of the digital still camera 100. However, according to another embodiment of the present invention, the digital still camera 100 may include a display device other than the LCD 116, For example, various data of the digital still camera 100 may be displayed using a display device such as an organic EL.

The SDRAM I / F 118 is an interface located between the SDRAM 120 and the SDRAM 120. The SDRAM I / F 118 mediates the writing or reading when writing data to the SDRAM 120 or reading data from the SDRAM 120 . The SDRAM 120 stores data (for example, image data) generated by the camera section 102, data developed by the developing section 110, image data compressed by the image compressing section 112 For example, coded image data) is temporarily stored.

Although not shown in FIG. 4, according to another embodiment, the digital still camera 100 may further include an input unit for accepting a user's input operation. The input unit may include a shutter button for executing photographing processing, an operation button for operating the digital still camera 100, and the like.

In the present embodiment, when image data is generated by the developing unit 110, the image data is directly supplied to the image compressing unit 112 without passing through the SDRAM 120. [ As described above, since the image data is directly supplied to the image compressing unit 112, the time required from the photographing by the camera unit 102 to the compression by the image compressing unit 112 is shortened, thereby increasing the processing speed .

The configuration of the digital still camera 100 according to the embodiment of the present invention has been described above with reference to Fig. Hereinafter, the configuration of the developing unit 110 included in the digital still camera 100 according to an embodiment of the present invention will be described.

5 is a block diagram showing the configuration of the developing unit 110 included in the digital still camera 100 according to an embodiment of the present invention. Hereinafter, the developing unit 110 included in the digital still camera 100 according to an embodiment of the present invention will be described with reference to FIG.

5, the developing unit 110 included in the digital still camera 100 according to an embodiment of the present invention includes first to third filter units 131a, 131b, 131c and a request control unit 132). 5, the developing unit 110 may further include an input DMA 133 and a JPEG buffer 134. [ The image compression unit 112 may include a JPEG encoding unit 141 and an output DMA 142. [

The first to third filter units 131a, 131b, and 131c perform filter processing on the data read from the SDRAM 120 by the input DMA 133, respectively. For example, the first filter unit 131a converts Bayer data into YUV data, the second filter unit 13lb performs noise reduction, and the third filter unit 131c performs correction such as emphasizing edges can do.

The request control unit 132 observes the number of output lines of the JPEG buffer 134 and controls the timing of inputting the lines to the JPEG buffer 134. The timing of inputting the line to the JPEG buffer 134 is controlled as described above so that the request control unit 132 can prevent the data from being newly input to the JPEG buffer 134 until the JPEG buffer 134 completes the output have. The request control unit 132 can control when the input DMA 133 and the first to third filter units 131a, 131b, and 131c output lines, i.e., the line output timing.

Upon reception of the request from the request control unit 132, the input DMA 133 reads the original image data stored in the SDRAM 120 in one line or a plurality of lines in the bottom direction from the top of the image data, And outputs it to the unit 131a. In this embodiment, three filter units 131a, 131b, and 131c are illustrated as shown in FIG. 5, but the number of filters is not limited in the present invention. The number of filters may be two or less or four or more. Hereinafter, filter processing by the first to third filter units 131a, 131b, and 131c of the developing unit 110 included in the digital still camera 100 according to an embodiment of the present invention will be described.

In general, in order for a digital still camera to perform a filtering process, a margin portion of the filter, that is, a ring pixel is required. The data output from the filter is the data from which the ring pixel portion is removed. However, if the ring pixel is removed as described above, the image data becomes smaller by the ring pixel portion. In particular, as the recent image data is gradually increased in image quality, the number of taps of the filter increases, and the number of pixels of the ring pixel also increases with the increase of the number of taps.

6 is a diagram showing a normal filter process for removing ring pixels. In Fig. 6, image data is input to each of the line memories corresponding to the last five lines (final line-4, final line-3, last line-2, last line-1, final line) in the vertical direction of the image data Respectively. As described above, the filter processing of the last five lines in the vertical direction of the image data is input to the line memory from the 'last line -4' to the last line, thereby performing the filter processing. In addition, the filter processing operation is terminated when inputted from the 'last line -4' to the last line in the line memory.

At this time, the first to third filter units 131a, 131b, and 131c of the digital still camera 100 according to an embodiment of the present invention may not perform the normal ring pixel removal operation as described above. The first to third filter units 131a, 131b, 131c according to the present embodiment perform filter processing (ringless processing) on image data by outputting image data having the same size as the size of input image data do. This ring-less processing may be performed by all of the first to third filter units 131a, 13lb, 131c, and may be performed only by the third filter unit 131c, which is the last unit according to another embodiment.

7 is a diagram illustrating filter processing by the first to third filter units 131a, 131b, and 131c of the developing unit 110 included in the digital still camera 100 according to an embodiment of the present invention. 7 also shows processing for the last five lines in the vertical direction of the image data as shown in Fig. 7, the first to third filter units 131a, 131b, and 131c of the digital still camera 100 according to the present embodiment include the last three lines (the last line-2, the last line- -1, final line) is input to the line memory. Further, the first to third filter units 131a, 131b and 131c input the remaining 2 lines (additional line + 1, additional line + 2) of the last line to the line memory. Thus, as image data is input to the line memory, filter processing for outputting image data of the same size as the size of the input image can be realized without removing the ring pixels.

Hereinafter, the filter processing by the first to third filter units 131a, 131b, and 131c will be briefly described. As described above, in this embodiment, the first filter unit 131a converts Bayer data into YUV data, the second filter unit 13lb performs noise reduction, and the third filter unit 131c performs edge reduction Correction and so on.

The first to third filters 131a, 131b and 131c according to the present embodiment are directly connected in series, and data output from each of the first to third filters 131a, 131b, Lt; / RTI > Each of the first to third filters 131a, 131b, and 131c performs a process of forming one pixel based on the pixels of a plurality of pixels, and when the process is performed on the input image, the corresponding pixels are reduced It is possible to add ring pixels to the lines input from the first to third filters 131a, 131b and 131c.

More specifically, when the JPEG buffer 134 outputs a line number smaller than the input number of lines, the request control unit 132 may not particularly control the first to third filter units 131a, 131b, and 131c All. The first to third filter units 131a, 131b, and 131c sequentially input lines, and the first to third filter units 131a, 131b, and 131c Detects that the input line is missing and inputs the lower ring line to the next filter or JPEG buffer 134. [

When the JPEG buffer 134 outputs one or more lines to one line input, the request control unit 132 controls the input DMA 133 (i. E., Until the output of all the lines of the original image data stored in the SDRAM 120) ) And the line output timing in the input DMA 133 can be controlled.

Specifically, when the request control unit 132 confirms that the JPEG buffer 134 has completed the output, the request control unit 132 requests the input DMA 133 to read the next line. Thereafter, the request controller 132 controls the first to third filters 131a, 131b, and 131c so that each lower ring line is input to the JPEG buffer 134 in accordance with the ring pixel frame added by each of the first to third filters 131a, 131b, And requests the first to third filter units 131a, 131b and 131c to output the lower ring lines in the order of the three filter units 131a, 131b, and 131c.

The order of the requests of the request control unit 132 can be determined in the following order. A represents the number of input lines obtained by dividing the original image data, B represents the number of output lines output from the third filter unit 131c so far, and B represents the number of output lines from the first filter unit 131a to the third filter unit 131b Let the number of ring lines be L1, L2, and L3, respectively. (L1 + L2 + L3) 'and' A- (L2 + L3) 'in the case of' A- (L1 + L2 + L3) It is assumed that there is an output line number B. In such a case, the request control section 132 requests the first filter section 131a to output the lower ring line in order from top to bottom.

If there is an output line number B between 'A- (L2 + L3) B' A-L3 ', that is, between' A- (L2 + L3) 'and' A- The second filter section 132 requests the second filter section 13lb to output the lower ring line in order from above.

Finally, when there is an output line number B between 'A-L3' and B 'A', that is, between A-L3 and A, the request control unit 132 controls the third filter unit 131c, The lower ring line is requested to be output in order from above.

The filter processing by the first to third filter units 131a, 131b, and 131c according to the embodiment is not limited to the example described above, and will be apparent to those skilled in the art.

The JPEG coding performed by the image compressing unit 112 is a coding based on the DCT, so it can be encoded only in the vertical 8-pixel unit. However, the image processing in the developing section 110 does not output more than the size of the Bayer. Thereby, for example, when the number of vertical lines is 100 lines, the last 4 lines are insufficient. According to the conventional technique, when the image data is encoded in units of 8 pixels vertically and the 8 pixels are not occupied at the lowermost portion, the last line is copied or the black data is inserted in a row not occupied by the 8 lines in the conventional technique.

The digital still camera 100 according to the embodiment of the present invention supplies the image data processed by the development unit 110 to the image compression unit 112 without going through the SDRAM 120, (Or the JPEG buffer 134) can be known from the image compression unit 112 (or the JPEG buffer 134). Therefore, the image compression unit 112 or the JPEG buffer 134 can perform the output processing on the first to third filter units 131a, 131b, and 131c. In FIG. 5, the JPEG buffer 134 instructs the request control unit 132 to process the first through third filter units 131a, 131b, and 131c.

Specifically, the digital still camera 100 according to an embodiment of the present invention can perform the following processing.

(1) When the frame is valid

And performs a general filter processing operation. The JPEG buffer 134 performs an operation according to a request for a line from the request control unit 132 while the IP of JPEG is timed in the image compressing unit 112.

(2) When the frame becomes invalid

When the line counter included in the first to third filter units 131a, 131b, and 131c starts to operate during the valid period of the frame, the request control unit 132 sets the first to third filters A request for ring-less processing is issued to the units 131a, 13lb, and 131c, and the ring-less processing operation is completed when a multiple of 8 is reached. Since the first to third filter units 131a, 131b, and 131c perform the ring-less processing as described above, the developing unit 110 can output image data that does not differ greatly from the input image do.

8 is a flowchart showing the operation of a digital still camera according to an embodiment of the present invention. The flowchart shown in Fig. 8 shows the filter processing of the developing section 110 in the digital still camera 100 according to an embodiment of the present invention. Hereinafter, the operation of the digital still camera 100 according to an embodiment of the present invention will be described with reference to FIG.

The JPEG buffer 134 obtains the number of vertical lines before JPEG encoding (S101). The JPEG buffer 134 transfers information on the number of vertical lines acquired in step S101 to the request control unit 132. [

When information on the number of vertical lines before JPEG encoding is transmitted from the JPEG buffer 134, the request control unit 132 determines whether the number of vertical lines is divided by 8, which is the number of vertical pixels of the MCU (S102).

As a result of the determination in step S102, if the number of vertical lines before JPEG encoding is a number of lines that do not divide by eight (S102: NO), the request control unit 132 determines whether the number of vertical lines is divided by eight, To the first to third filter units 131a, 13lb, and 131c to insert the additional line into the line memory until the number of vertical lines including the added line (additional line) is divided by 8 (S103 ).

If it is determined in step S102 that the number of vertical lines before JPEG encoding is divided by 8 (S102: YES), the request control unit 132 controls the first to third filter units 131a, 131b, and 131c ). When the request control unit 132 requests the addition of additional lines to the first to third filter units 131a, 13lb and 131c in step S103, the first to third filter units 131a, 131b, and 131c, The DMA 133 performs filter processing on data read from the SDRAM 120, that is, filter processing according to ring-less processing (S104).

9 is a diagram illustrating filter processing by the first to third filter units 131a, 131b, and 131c of the developing unit 110 included in the digital still camera 100 according to an embodiment of the present invention. Fig. 9 shows the processing for the last five lines in the vertical direction of the image data as shown in Figs. 6 and 7. Fig.

First, the first filter section 131a inputs the last three lines (the last line-2, the last line-1, and the last line) to the line memory, 1 and an additional line + 2) to the line memory and outputs it. Subsequently, the second filter section 13lb inputs the last two lines (final line-1, final line) into the line memory, and adds the remaining three lines (additional line + 1, additional line + Line +3) to the line memory and outputs the same. Finally, the third filter unit 131c inputs the last line to the line memory, and adds the remaining 4 lines (additional line + 1, additional line + 2, additional line 3, additional line + 4) And outputs it to the line memory.

As described above, the filter processing according to the present invention sequentially inputs data of the last line into the line memory. Compared with a method of performing JPEG coding by copying the last line or inserting black data for a row in which the filter processing according to the prior art does not reach 8 lines, the filter processing according to the present invention improves the image quality under the image data, Thus, more natural image data can be obtained.

10 is a block diagram illustrating the configuration of a digital still camera including a developing unit according to another embodiment of the present invention. Hereinafter, a digital still camera including a developing unit according to another embodiment of the present invention will be described with reference to FIG.

10, the developing unit 110 included in the digital still camera 100 according to another embodiment of the present invention includes first to third filter units 131a, 131b and 131c, a request control unit 132 and an operation unit 135. [ 10, the developing section 110 further comprises an input DMA 133 and a JPEG buffer 134. [ The image compressing unit 112 may include a JPEG encoding unit 141 and an output DMA 142.

The arithmetic operation unit 135 may include an output line number register 151, a subtractor 152, a divider 153 and an adder 154.

In the output line number register 151, the number of vertical lines of encoded image data after encoding by JPEG is recorded. The subtraction section 152 subtracts the number of output lines recorded in the output line number register 151 from the number of vertical pixels of one MCU to eight. The divider 153 divides the subtraction result of the subtracter 152 into two. The addition unit 154 adds the number of output lines written in the output line number register 151 and the division result by the divider 153 and outputs the result.

The CPU 104 can write the number of output lines to the output line number register 151 since the number of vertical lines of the coded image data after JPEG encoding can be known in advance. Subtraction unit 152 subtracts 3 bits of LSB from the number of output lines written in output line number register 151 to 8, which is the number of vertical pixels of one MCU, and sends the subtraction result to divider 153 do. The divider 153 divides the subtraction result of the subtracter 152 into two. The addition unit 154 adds the number of output lines written to the output line number register 151 and the dividing result of the divider 153 and outputs the addition result to the request control unit 132 as the number of output lines.

When the operation unit 135 calculates the number of output lines and outputs the calculated number of output lines to the request control unit 132 as described above, the first to third filter units 131a, 131b, So that the JPEG coding according to the present embodiment makes it possible to obtain a more natural image.

For example, when it is assumed that the arithmetic operation unit 135 outputs 4 as a remainder obtained by dividing the number of vertical lines of the encoded image data after JPEG encoding by 8, the request control unit 132 issues a request for the first two lines. When the filter processing for the image is performed by the first to third filter units 131a, 131b, and 131c, the first through third filter units 131a, 131b, The data copied from the last line can be inserted into the line memory. By sharing the filter processing above and below the screen as described above, it is possible to obtain a more natural image than when only JPEG encoding is performed.

3. Conclusion

As described above, according to the digital still camera 100 according to the embodiment of the present invention, the developing unit 110 generates image data composed of YCbCr information including a luminance signal and a color difference signal, Is supplied to the image compression unit 112 without passing through the SDRAM 120. The development unit 110 divides one image into a plurality of tiles and supplies the image to the image compression unit 112. [ The image compression unit 112 performs variable length coding on the image data in units of tiles.

The development unit 110 of the digital still camera 100 according to an embodiment of the present invention performs filter processing according to the ring-less processing, but since the JPEG encoding is performed on an MCU basis, it can be encoded only in units of eight vertical lines . Accordingly, the developing unit 110 according to the present invention performs filter processing using the first to third filter units 131a, 131b, and 131c, And performs filter processing by inserting it into the memory. In this way, the digital still camera 100 can obtain a more natural image even after performing JPEG coding.

Although the preferred embodiments of the present invention have been described in detail with reference to the accompanying drawings, the present invention is not limited to these examples. It will be apparent to those skilled in the art that various changes and modifications can be made without departing from the scope of the invention as defined in the appended claims. It is understood that the invention is within the technical scope of the invention.

100: digital still camera 102: camera unit
104: CPU 105: ROM
106: Multiplexer 110:
112: image compression section 113: distortion correction processing section
114: memory card 116: LCD
118: SDRAM I / F 120: SDRAM

Claims (5)

An image processing section for generating image data from light input to the image pickup device,
An encoding unit for encoding the image data to generate encoded image data;
And a storage unit for storing the encoded image data,
Wherein the image processing section divides the image data into a plurality of blocks in the horizontal direction and supplies the divided data to the encoding section,
Wherein the image processing unit comprises:
At least one filter unit for performing predetermined filter processing on the image data,
And a filter control unit for controlling a filter process of the filter unit,
Wherein the filter control unit comprises:
The data of the last row of the image data is copied until the number of vertical pixels of the image data is divided by the number of vertical pixels divided by a predetermined number of vertical pixels Wherein the control unit controls the filter unit to add the image data. The method according to claim 1, wherein the predetermined filter processing performed by the filter unit comprises:
Wherein the number of pixels of the input data is equal to the number of pixels of the output data. The method according to claim 1,
Wherein the image processing unit includes at least two filter units,
Wherein the at least two filter units are cascade-connected and the filter unit at the rearmost end of the at least two filter units performs a filtering process so that the number of pixels of the input data matches the number of pixels of the output data. The image processing apparatus according to claim 1,
Wherein when the number of vertical pixels of the coded image data is not divided by the number of vertical pixels which are coded units, the number of vertical pixels of the coded image data is divided into upper and lower portions of the image data, And generates an image of the object. An image processing step of generating image data from light input to the image pickup element,
A coding step of coding the image data to generate coded image data;
And a storage step for storing the encoded image data,
In the image processing, if the image data is divided into a plurality of blocks in a horizontal direction, the image data is encoded in the encoding process,
Wherein the image processing step comprises:
At least one filter process for performing a predetermined filter process on the image data,
And a filter control step of controlling the filter processing in the filter processing step,
The filter control process includes:
Wherein the image data is obtained by dividing the vertical pixel number of the image data by the number of vertical pixels divided by the number of vertical pixels in the encoding process, And controlling the filter process in the filter process so that the data of the row is copied and added to the image data.

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