JP2005223490A - Image processor and image processing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To shorten the processing time required for executing resolution conversion processing and YUV format conversion processing. <P>SOLUTION: A corrector 12 corrects a horizontal or vertical magnification/reduction rate stored in a setting information storage unit 11 corresponding to YUV format information of an input image, YUV format information of an output image, and processing component designation information stored in the setting information storage part 11. A magnification/reduction rate storage part 13 stores the corrected magnification/reduction rate as a new magnification/reduction rate used for the resolution conversion processing. By this, the YUV format conversion processing is simultaneously executed in the resolution conversion processing using the corrected magnification/reduction rate. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an image processing apparatus, and more particularly to an image processing apparatus and an image processing method for performing resolution conversion processing and format conversion from YUV to another format YUV (hereinafter referred to as YUV format conversion processing).

  Various types of image processing such as image resolution conversion processing, RGB to YUV or vice versa YUV to RGB format conversion processing, YUV format conversion processing are performed in various multimedia devices such as mobile phones and digital still cameras. Yes.

  Such image processing can be performed by software means. In such a case, a technique for performing image processing such as enlargement / reduction by hardware is known because of the problem that calculation time is required (for example, Patent Document 1).

There are mainly the following three types of image processing apparatuses that perform image resolution conversion processing and format conversion.
10, 11 and 12 are block diagrams of a conventional image processing apparatus.

  A conventional image processing apparatus 800a shown in FIG. 10 generates a CPU (Central Processing Unit) 801 that controls each part of the image processing apparatus 800a, a bus arbiter 802 that controls bus occupancy, and a signal that decodes an address and selects a module. An address decoder 803, a memory controller 804 that controls a video random access memory (VRAM) 804a, a scaler 805 that performs image resolution conversion processing, a format converter 806 that performs format conversion, and an image processing module 807-1 that performs other image processing , 807-n are connected to the system bus 808, respectively.

  For example, when performing resolution conversion processing of an image in the YUV format, the scaler 805 normally applies the same enlargement / reduction ratio to all components Y, U, and V to enlarge or reduce the image.

  The format converter 806 performs various format conversion processes such as RGB to YUV or vice versa, YUV to RGB format conversion, and YUV format conversion processing.

  The YUV format uses the property that “the human eye is sensitive to changes in brightness but is insensitive to changes in color”, suppresses chromaticity, and assigns a wider band and bit number to luminance. Therefore, it is a format that realizes efficient transmission and compression with little loss. There are several formats depending on how the color difference components are thinned out during sub-sampling. The main ones are YUV444 (having one “U” and one “V” per pixel. No thinning of color difference components), YUV422 (one “U” and one “2” in two pixels arranged in the horizontal direction). V ”is shared. Color difference components are thinned out in the horizontal direction), YUV 411 (one“ U ”and one“ V ”are shared in four pixels arranged in the horizontal direction. Color difference components are thinned out in the horizontal direction), YUV420 (The 2 × 2 block (4 pixels) shares one “U” and one “V”. The color difference component is thinned out by the block), and YUV410 (4 × 4 block (16 pixels) has one “U”. "And one" V "are shared. Color difference components are thinned out in blocks).

  On the other hand, the conventional image processing apparatus 800b shown in FIG. 11 has a configuration in which a scaler 805 and a format converter 806 are locally connected and connected to the system bus 808 as one module 809. The other components are the same as those shown in FIG.

  A conventional image processing apparatus 800c shown in FIG. 12 has a configuration in which a certain image processing module 807-i has a format converter 806 built therein. The other components are the same as those shown in FIG.

10, 11, and 12, conventional processing when both resolution conversion processing and format conversion are performed will be described below.
13 and 14 are flowcharts for explaining the flow of processing when performing both resolution conversion processing and format conversion in a conventional image processing apparatus.

  Here, the flow of processing when a resolution conversion process is first performed on a YUV image and then a YUV format conversion process is performed is shown. Both conversions are performed for each unit block image data. The frame buffer corresponds to the VRAM 804a shown in FIGS.

  When the processing starts, the memory controller 804 controlled by the CPU 801 reads out, for example, image data of a unit block of 4 × 4 pixels necessary for interpolation when performing resolution conversion processing from the frame buffer (step S50). The read image data is sent to the scaler 805 via the system bus 808 under the control of the CPU 801, and resolution conversion processing is performed by the scaler 805 (step S51).

  When the resolution conversion process for the read image data is completed, the image data after the resolution conversion process is written again into the VRAM 804a via the system bus 808 under the control of the CPU 801 (step S52). The above processing is repeated for one horizontal direction. When the process in one horizontal direction is completed, the process proceeds to step S54 (step S53). When the resolution conversion processing for one horizontal direction is completed, the vertical direction address is changed (step S54), and the processing from step S50 to step S54 is repeated for the next row. If all the vertical processing is completed, the process proceeds to step S56 (step S55). When the processing of steps S50 to S55 for one processing component, for example, luminance Y is completed as described above, the number of processing components is set to N = N + 1 (step S56). The processes of S50 to 56 are repeated. When the above processing is completed for all YUV (N = 3), the process proceeds to step S58 (step S57).

FIG. 15 is a diagram illustrating a state of normal resolution conversion processing.
Here, for the sake of simplicity, a case has been described in which an 8 × 8 pixel image in YUV420 format is enlarged twice in both the horizontal and vertical directions to obtain a 16 × 16 pixel image. One square represents one pixel. In the YUV420 format, the number of color difference components U and V is ¼ of the luminance component. Therefore, when drawn in a form with thinned out portions as shown in the figure, the size of the color difference components U and V before enlargement is 4 × 4 pixels. It is. By using various pixel interpolation methods such as bicubic method, bilinear method, and nearest neighbor method for such image data, an 8 × 8 pixel image is doubled to obtain a 16 × 16 pixel image. It is done. Note that the color difference components U and V are 8 × 8 pixels when drawn in a form that is doubled and thinned out.

  In this way, for example, a QVGA image (320 × 240 pixels) is similarly converted to a VGA image (640 × 480 pixels) by doubling all components of Y, U, and V. Can do.

The process from step S58 is a YUV format conversion process.
Similarly to the resolution conversion process, when performing the YUV format conversion process, image data is read out from the VRAM 804a in units of blocks (step S58). Then, the read image data is sent to the format converter 806, and is converted into another YUV format such as YUV420 to YUV422, for example (step S59). The image data after the format conversion is written again into the VRAM 804a (step S60). The above processing is repeated for one horizontal direction. When the process is completed for one horizontal direction, the process proceeds to step S62 (step S61). When the format conversion for one horizontal direction is completed, the vertical direction address is changed (step S62), and the processing from step S58 to step S62 is repeated for the next row. If all the vertical processing is completed, the process proceeds to step S64 (step S63). When the processing for one color difference component (U component or V component) is completed as described above, the number of processing components N = N + 1 is set (step S64), and the above-described steps S58 to S58 are similarly performed for the remaining one color difference component. The process of S64 is repeated. When the above processing is completed for both the U component and the V component (N = 2), the resolution conversion processing and the format conversion processing are ended (step S65).
JP 2000-357224 A

  However, as described above, conventionally, both the resolution conversion process and the YUV format conversion process are performed by separately accessing the frame buffer, so that it takes a long processing time to obtain an output image. was there.

  In general, multimedia processing systems that handle still images and moving images perform heavy processing such as video encoding / decoding, still image compression / decompression, and camera image color interpolation in addition to resolution conversion processing and format conversion. Many coexist, and it takes a lot of processing time to obtain an output image.

In addition, an increase in the number of image processing modules leads to an increase in circuit area, which becomes a serious problem particularly when applied to a system for portable devices where the mounting area is limited.
The present invention has been made in view of these points, and an object thereof is to provide an image processing apparatus capable of simultaneously performing resolution conversion processing and YUV format conversion processing with a single scaler.

  Another object of the present invention is to provide an image processing method capable of simultaneously performing resolution conversion processing and YUV format conversion processing.

  In the present invention, in order to solve the above problems, in an image processing apparatus that performs resolution conversion processing and YUV format conversion processing, as shown in FIG. 1, YUV format information of an input image, YUV format information of an output image, and horizontal A setting information storage unit 11 that stores a scaling factor in the direction and a scaling factor in the vertical direction, and processing component designation information that designates which component of luminance or two chrominance components is to be processed, and YUV of the input image A correction unit 12 that corrects the enlargement / reduction ratio in the horizontal direction or the vertical direction according to the format information, the YUV format information of the output image, and the processing component designation information, and a new one that uses the corrected enlargement / reduction ratio in the resolution conversion process. There is provided an image processing apparatus including an enlargement / reduction rate storage unit 13 that stores the enlargement / reduction rate.

  According to the above configuration, the correction unit 12 sets the setting information storage unit 11 according to the YUV format information of the input image, the YUV format information of the output image, and the processing component designation information stored in the setting information storage unit 11. The horizontal / vertical enlargement / reduction ratio stored in 1 is corrected, and the enlargement / reduction ratio storage unit 13 stores the corrected enlargement / reduction ratio as a new enlargement / reduction ratio used in the resolution conversion process. Thereby, in the resolution conversion process using the corrected enlargement / reduction ratio, the YUV format conversion process is performed simultaneously.

  In the present invention, the original horizontal or vertical enlargement / reduction ratio is corrected according to the YUV format information of the input image, the YUV format information of the output image, and the processing component designation information, and the corrected enlargement / reduction ratio is obtained. Since the used resolution conversion process is performed, the YUV format conversion process can be performed simultaneously with the resolution conversion process.

  As a result, the number of accesses to the frame buffer is reduced, and the processing time can be shortened. In addition, since the YUV format conversion process can be performed not by the format converter but by the scaler, the function of the format converter can be reduced and the entire circuit area can be reduced.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a diagram showing a characteristic part of the image processing apparatus according to the first embodiment of the present invention.
FIG. 2 is a diagram showing the configuration of the image processing apparatus according to the first embodiment of the present invention.

FIG. 3 is a diagram showing the configuration of the scaler of the image processing apparatus according to the first embodiment of the present invention.
Hereinafter, for the convenience of description, the configuration of the image processing apparatus shown in FIG. 2 will be described.

  The image processing apparatus 100 according to the first embodiment of the present invention includes a CPU 101 that controls each unit of the image processing apparatus 100, a bus arbiter 102 that controls bus occupation, and an address decoder that generates a signal that decodes an address and selects a module. 103, a memory controller 104 that controls the VRAM 104a, a scaler 200 that performs image resolution conversion processing, a format converter 105 that performs format conversion processing such as RGB to YUV format, or vice versa, YUV format to RGB format conversion, etc. The image processing modules 106-1 to 106-n that perform image processing are connected to the system bus 107, respectively.

  The scaler 200 performs image resolution conversion processing as in the conventional case, but the scaler 200 according to the first embodiment of the present invention can perform YUV format conversion processing simultaneously with the resolution conversion processing.

  As shown in FIG. 3, the scaler 200 includes a resolution conversion processing unit 210 that performs resolution conversion processing, an input buffer 220 that holds data input via the system bus 107 and inputs the data to the resolution conversion processing unit 210, and resolution An output buffer 230 that holds output data from the conversion processing unit 210 and sends it to the system bus 107, a coefficient unit 240 that outputs a calculation coefficient for determining pixel weights during resolution conversion processing, and a feature of the present invention A register unit 10 is provided.

  The input buffer 220 holds source data to be subjected to enlargement / reduction processing stored in the VRAM 104a (see FIG. 2) in response to a read request from the scaler 200 to the memory controller 104 or a write request from the CPU 101.

The output buffer 230 holds the data after the enlargement / reduction processing to be output to the VRAM 104a.
The coefficient unit 240 stores coefficients for determining the weights of the pixels in the window to be referred to at the time of resolution conversion processing, for example, 4 pixels if 2 × 2 pixels, and outputs the coefficients to the resolution conversion processing unit 210. This coefficient is one factor that determines the image quality. For example, a B-spline coefficient is used.

Further, the resolution conversion processing unit 210 includes an input control unit 211, an output control unit 212, a product-sum operation unit 213, and an operation control unit 214.
The input control unit 211 issues a read request for image data stored in the VRAM 104 a to the memory controller 104. Also, necessary image data is output to the product-sum calculator 213.

The output control unit 212 writes the calculation result in the output buffer 230. It also issues a data write request after the enlargement / reduction processing to the memory controller 104.
The product-sum operation unit 213 performs an operation of K0 × D0 + K1 × D1 + K2 × D2 + K3 × D3 when, for example, referring to a neighboring 2 × 2 pixel when processing a certain operation point. Here, K0 to K3 are calculation coefficients output from the coefficient unit 240, and D0 to D3 are pixel data (values of Y, U, and V in the pixel).

The arithmetic control unit 214 performs control such as start / end of resolution conversion processing and issuance of an interrupt.
The register unit 10 is a characteristic unit of the image processing apparatus 100 according to the first embodiment of the present invention, and sets an enlargement / reduction ratio when performing resolution conversion processing.

  As shown in FIG. 1, the register unit 10 in the image processing apparatus 100 according to the first embodiment of the present invention includes a setting information storage unit 11 that stores various setting information, and setting information for YUV format conversion processing. The horizontal enlargement / reduction ratio stored in the storage unit 11 (hereinafter also referred to as X-enlargement / reduction ratio) and the vertical enlargement / reduction ratio (hereinafter also referred to as Y-enlargement / reduction ratio) may be used. A correction unit 12 for correction and an enlargement / reduction rate storage unit 13 for storing the corrected enlargement / reduction rate are provided.

  The setting information storage unit 11 includes YUV format information of the input image (hereinafter abbreviated as input YUV format), YUV format information of the output image (hereinafter abbreviated as output YUV format), X-enlargement / reduction ratio, and Y-enlargement / reduction ratio. And a plurality of registers 11a, 11b, 11c, 11d, and 11e for storing processing component designation information for designating which component of luminance or two color difference components is to be processed.

These pieces of information are stored in the setting information storage unit 11 under the control of the CPU 101 shown in FIG. 2, for example, by user input via an input interface (not shown).
Although not shown, the setting information storage unit 11 stores processing start / mode designation information, interrupt status, interrupt enable, source data transfer start address, data after resolution conversion processing, in addition to the above information. A transfer start address, a horizontal size of an input image (= Y component), a horizontal size and a vertical size of an output image (= Y component), and the like are stored.

  The correction unit 12 corrects the X-enlargement / reduction rate and the Y-enlargement / reduction rate according to the input YUV format, the output YUV format, and the processing component designation information stored in the setting information storage unit 11. More specifically, a correction coefficient Ax for the horizontal enlargement / reduction ratio and a correction coefficient Ay for the enlargement / reduction ratio in the vertical direction are obtained according to the input YUV format, the output YUV format, and the processing component designation information. The correction coefficient Ax is corrected by multiplying the X-enlargement / reduction ratio stored in the setting information storage unit 11, and the correction coefficient Ay is corrected by multiplying the Y-enlargement / reduction ratio.

The correction coefficients Ax and Ay are given by a table as shown below and stored in the correction unit 12.
FIG. 4 is an example of a correction coefficient determination table stored in the correction unit.

  As shown in the figure, correction coefficients Ax and Ay are obtained according to the input YUV format, the output YUV format, and the processing components specified by the processing component specifying information. For example, when the input YUV format is YUV444 and the output YUV format is YUV422, if the processing component is a luminance (Y) component, both the correction coefficients Ax and Ay are 1, and the processing component is a color difference (U or V) component. Then, the correction coefficient Ax is 1/2 and the correction coefficient Ay is 1. In the case of normal resolution conversion processing in which the input YUV format and the output YUV format are the same, the correction coefficient Ax = Ay = 1 regardless of the processing component. In this case, illustration is omitted.

Further, since the luminance component is not thinned out in the YUV format conversion process, the correction coefficients Ax and Ay are always 1 when the luminance component is processed.
As described above, the enlargement / reduction ratio is corrected by multiplying the correction coefficients Ax and Ay. However, as can be seen from FIG. 4, since there are only factors 1, 2 and 4, it is sufficient to actually perform the bit shift operation. End up. For example, when the correction coefficient Ax or Ay is ½, the enlargement / reduction ratio may be shifted 1 bit to the right, and when the correction coefficient Ax or Ay is 4, it may be shifted 2 bits to the left. Therefore, the correction unit 12 can be realized by a shift register.

  The enlargement / reduction ratio storage unit 13 stores the corrected enlargement / reduction ratio as a new enlargement / reduction ratio used in the resolution conversion process. The X-enlargement / reduction ratio after the correction process is set in the register 13a, and the Y-enlargement / reduction ratio after the correction process is set in the register 13b.

  Hereinafter, the operation of the image processing apparatus 100 according to the first embodiment of the present invention will be described by taking, as an example, the case where an 8 × 8 pixel YUV420 format image is converted to a double 16 × 16 pixel YUV422 format image. Will be explained.

FIG. 5 is a flowchart for explaining the flow of processing when performing both resolution conversion processing and format conversion in the image processing apparatus according to the first embodiment of the present invention.
When the process starts, the memory controller 104 controlled by the CPU 101 reads out the image data of the unit block necessary for interpolation when performing the resolution conversion process from the VRAM 104a (frame buffer) (step S10). The read image data is sent to the scaler 200 through the system bus 107 under the control of the CPU 101, and the scaler 200 performs resolution conversion processing and YUV format conversion processing (step S11).

  When converting an 8 × 8 pixel YUV420 format image into a double 16 × 16 pixel YUV422 format image, the setting information storage unit 11 of the register unit 10 in FIG. An input YUV420 format is set in the register 11a, and an output YUV422 format is set in the register 11b. The register 11c is set with a horizontal scaling factor of "2", and the register 11d is also set with a vertical scaling factor of "2". For example, when processing the Y component first, the Y component is set as the processing component in the register 11e.

  When processing is performed for the Y component, the correction coefficients Ax and Ay obtained by the correction unit 12 are both “1” as shown in FIG. Therefore, the enlargement / reduction rate set in the registers 13a and 13b of the enlargement / reduction rate storage unit 13 is "2", which is the same as that set in the registers 11c and 11d of the setting information storage unit 11. The resolution conversion processing unit 210 illustrated in FIG. 3 performs resolution conversion processing using the enlargement / reduction ratio set in the registers 13a and 13b of the enlargement / reduction ratio storage unit 13.

  When processing the U component or the V component that is the color difference component, the correction unit 12 determines the correction coefficients Ax and Ay with reference to the correction coefficient determination table as illustrated in FIG. When converting from YUV420 to YUV422, the horizontal correction coefficient Ax is “1” and the vertical correction coefficient Ay is “2”. The correction coefficients Ax and Ay obtained here are multiplied by the enlargement / reduction ratio set in the registers 11c and 11d of the setting information storage unit 11. Multiplication of the correction coefficient Ay of “2” is realized by 1-bit left shift. As a result, the X-enlargement / reduction ratio and the Y-enlargement / reduction ratio are both “2”, the X-enlargement / reduction ratio is “2”, and the Y-enlargement / reduction ratio is “4”. The rate is set in the registers 13a and 13b of the enlargement / reduction rate storage unit 13, respectively.

The resolution conversion process in the resolution conversion processing unit 210 is performed as follows.
6A and 6B are diagrams illustrating a state in which the resolution conversion process is performed twice in the horizontal direction. FIG. 6A illustrates a processing position in a certain process, and FIG. 6B illustrates a processing position in a process subsequent to (A). Is shown.

  In the resolution conversion process, for example, a window 51 having a size of 2 × 2 pixels is moved with respect to the source pixel 50 of the unit block of the image data read from the VRAM 104a. Here, as shown in FIG. 6A, the value of the processing position 52 is obtained by a product-sum operation with reference to the source pixels 50a, 50b, 50c, and 50d in the window 51. Note that the processing position 52 in FIG. 6A is assumed to be at the midpoint between pixels both vertically and horizontally.

  The product-sum calculator 213 calculates K0 × D0 + K1 × D1 + K2 × D2 + K3 × D3 under the control of the calculation control unit 214, and obtains a value at the processing position 52. The calculation coefficients K0 to K3 are determined by the distance between the source pixels 50a, 50b, 50c, and 50d in the window 51 and the processing position 52. In the case of FIG. 6A, the source pixels 50a, 50b, 50c, and 50d all have the same weight.

  The processing pitch for moving the window 51 for the next processing is the reciprocal of the enlargement / reduction ratio set in the registers 13a, 13b of the enlargement / reduction ratio storage unit 13, respectively. When the enlargement / reduction ratio in the horizontal direction is double, the processing pitch is ½ pixel interval in the horizontal direction. FIG. 6B shows a processing position 53 in the next processing of FIG. The window 51 is moved by ½ pixel in the horizontal direction. At this time, in the window 51, one source pixel 50c, 50d is present, and the source pixels 50a, 50b, 50e, 50f are present in half. In this case, for example, a rule of referring to the right source pixels 50e and 50f is determined. 6B, the weights of the source pixels 50c and 50d that are close to the processing position 53 are heavier than those of the right source pixels 50e and 50f.

  Thus, by moving the window 51 in the horizontal direction at intervals of ½ pixel and obtaining a value for each window 51, it is possible to perform a resolution conversion process that is doubled in the horizontal direction. When the window 51 comes to the right end of the original image stored in the frame buffer, there are cases where the source pixel 50 to be referenced is lost. At this time, for example, the processing is performed by extending the rightmost source pixel 50 to the right side.

Similarly, by obtaining the window 51 by moving the window 51 in the vertical direction at intervals of ½ pixel, it is possible to perform double the resolution conversion processing in the vertical direction.
Similarly, for other enlargement / reduction ratios, a value is obtained by moving the window 51 in the horizontal or vertical direction at a processing pitch inverse to the enlargement / reduction ratio set in the registers 13a and 13b of the enlargement / reduction ratio storage unit 13. By doing so, it is possible to perform resolution conversion processing at a predetermined enlargement / reduction ratio. For example, by moving the window 51 in the horizontal direction at intervals of 2 pixels to obtain a value, a 1 / 2-fold resolution conversion process can be performed.

  When the resolution conversion process is completed for the read image data, the obtained image data is sent from the output buffer 230 to the system bus 107 under the control of the output control unit 212, and the VRAM (frame) is controlled under the control of the memory controller 104. Buffer) 104a is written (step S12).

  The processes in steps S10 to S12 are repeated for one horizontal direction. When the process in one horizontal direction is completed, the process proceeds to step S14 (step S13). When the resolution conversion process for one horizontal direction is completed, the vertical direction address is changed (step S14), and the processes from step S10 to step S14 are repeated. If all the vertical processing is completed, the process proceeds to step S16 (step S15). When the processing in steps S10 to S15 for one processing component, for example, luminance Y, is completed as described above, the number of processing components N = N + 1 is set (step S16). Thereafter, under the control of the CPU 101, for example, the color difference U is set in the register 11e as the processing component setting information of the setting information storage unit 11, and the processing of steps S10 to S16 is repeated. When the above process is completed for all YUV (N = 3), the process is terminated (step S17).

  FIG. 7 is a diagram showing a state of resolution conversion processing and YUV format conversion processing from an 8 × 8 pixel YUV420 format image to a 16 × 16 pixel YUV422 format image.

  An image in the YUV420 format is a format in which one “U” and one “V” are shared by 2 × 2 blocks (4 pixels), and color difference components are thinned out by the blocks. That is, in the case of an 8 × 8 pixel image, the size of the color difference component (U component, V component) is 4 × 4 pixels when the thinning is reduced.

  On the other hand, an image in the YUV422 format is a format in which two “pixels” arranged in the horizontal direction share one “U” and one “V” and thin out the color difference component in the horizontal direction. In the case of an image of 16 × 16 pixels, the size of the color difference component (U component, V component) is 8 × 16 pixels after thinning out.

  In the present invention, as described above, the correction unit 12 corrects the X-enlargement / reduction ratio and the Y-enlargement / reduction ratio, and both the X-enlargement / reduction ratio and the Y-enlargement / reduction ratio are 2 for the Y component. The Y-enlargement / reduction ratio is quadrupled by multiplying the color difference components U and V by “2” of the correction coefficient Ay in the vertical direction. Accordingly, the double resolution conversion process from 8 × 8 pixels to 16 × 16 pixels and the YUV format conversion process from the YUV420 format image to the YUV422 format image can be performed simultaneously.

  As described above, according to the image processing apparatus 100 of the first embodiment of the present invention, the resolution conversion process is performed by correcting the enlargement / reduction ratio used in the resolution conversion processing unit 210 according to the YUV format of the output image. And the YUV format conversion process can be performed simultaneously by the scaler 200.

  As a result, the number of accesses to the frame buffer is reduced, and the processing time can be shortened. Further, since the YUV format conversion process can be performed not by the format converter 105 but by the scaler 200, the function of the format converter can be reduced and the entire circuit area can be reduced.

Next, an image processing apparatus according to a second embodiment of the present invention will be described.
The image processing apparatus according to the second embodiment of the present invention is different in a portion corresponding to the register unit 10 in the first embodiment. The other components are almost the same.

FIG. 8 is a diagram illustrating a characteristic part of the image processing apparatus according to the second embodiment of the present invention.
The register unit 20 which is a characteristic unit of the image processing apparatus according to the second embodiment of the present invention is a part corresponding to the register unit 10 according to the first embodiment. The setting information storage unit 21 includes registers 21a, 21b, 21c, 21d, and 21e in which various pieces of setting information are set, like the register unit 10 of the first embodiment. However, unlike the register unit 10 in the first embodiment, processing order designation information is stored instead of processing component designation information.

  The enlargement / reduction ratio storage unit 23 including the correction unit 22 and registers 23a and 23b in which the corrected enlargement / reduction ratio is stored has the same configuration as the register unit 10 of the first embodiment. However, in the register unit 20 according to the second embodiment, a processing component setting unit 24 that sets processing components for performing resolution conversion processing and YUV format conversion processing in the correction unit 22 in an order according to processing order designation information. have.

  For example, the processing order designation information is set in the setting information storage unit 21 under the control of the CPU 101 in accordance with a user input. Information specifying the order of components to be processed (Y, U, V components).

  Image processing apparatus according to the second embodiment having the register unit 20 having such a configuration (the entire configuration is the same as that of the image processing apparatus 100 according to the first embodiment shown in FIG. ) Will be briefly described.

  The operation of the image processing apparatus of the second embodiment is almost the same as the processing flow shown in FIG. 5, but when the processing end flag for one processing component is detected in the processing of step S16, the processing order is designated. The processing component setting unit 24 is automatically updated to the next processing component according to the information.

This eliminates the need to reset the processing component when the processing for one processing component is completed.
In the first and second embodiments, for example, the correction units 12 and 22 correct the X-enlargement / reduction ratio and the Y-enlargement / reduction ratio at high speed with hardware, and the resolution conversion processing unit 210 performs the correction. The case where the resolution conversion process and the YUV format conversion process can be performed simultaneously has been described. However, for example, in response to a user input, the CPU 101 determines a correction coefficient with reference to a correction coefficient determination table as shown in FIG. 4 stored in a ROM (Read Only Memory) (not shown), for example, and performs resolution in software. The X-enlargement / reduction ratio and Y-enlargement / reduction ratio used in the conversion processing unit 210 may be corrected. The outline of the process is shown below.

FIG. 9 is a flowchart showing an image processing method according to the embodiment of the present invention.
When the process is started, setting information such as an input YUV format, an output YUV format, an X-enlargement / reduction ratio, and a Y-enlargement / reduction ratio is input from the user via an input interface (not shown), for example (step S20).

  Thereafter, the CPU 101 refers to the input YUV format and the output YUV format, and further stores them in, for example, a ROM (not shown) depending on which of the three processing components consisting of luminance or two color difference components is processed. The correction coefficients Ax and Ay are determined by the correction coefficient determination table as shown in FIG. 4 (step S21).

  Next, the correction factors Ax and Ay are multiplied by the inputted X-enlargement / reduction rate and Y-enlargement / reduction rate, thereby correcting the X-enlargement / reduction rate and the Y-enlargement / reduction rate (step S22).

  Finally, using the X-enlargement / reduction ratio and the Y-enlargement / reduction ratio corrected in the process of step S22, the resolution conversion processing unit 210 performs the processes of steps S10 to S17 as shown in FIG. At this time, when the processing component is updated in the process of step S17, the resolution for each of the YUVs using the X-enlargement / reduction ratio and the Y-enlargement / reduction ratio in the processing component corrected in the processes of steps S21 and S22 of FIG. Conversion processing is performed by the scaler 200 (step S23).

  By using the X-enlargement / reduction ratio and the Y-enlargement / reduction ratio corrected in steps S21 and S22 in the resolution conversion process in step S23, the scaler 200 can perform the YUV format conversion process simultaneously with the resolution conversion process. Thereby, processing time can be shortened rather than performing resolution conversion processing and YUV format conversion processing separately. In addition, since the YUV format conversion process can be performed by the scaler 200, the circuit scale of the format converter 105 can be reduced, and the circuit area of the entire image processing apparatus can be reduced.

  In the above description, YUV is used, but it may be replaced with YCbCr. That is, the present invention can be similarly applied even if U is replaced with Cb and V is replaced with Cr. Y is both the Y-axis of the chromaticity diagram determined by the Commission Internationale del Eclairage (CIE).

  The present invention is applied to image processing in various multimedia devices such as a mobile phone and a digital still camera.

It is a figure which shows the characteristic part of the image processing apparatus of the 1st Embodiment of this invention. It is a figure which shows the structure of the image processing apparatus of the 1st Embodiment of this invention. It is a figure which shows the structure of the scaler of the image processing apparatus of the 1st Embodiment of this invention. It is an example of the correction coefficient determination table stored in a correction | amendment part. 6 is a flowchart for explaining a flow of processing when performing both resolution conversion processing and format conversion in the image processing apparatus according to the first embodiment of the present invention. It is a figure which shows a mode that a double resolution conversion process is performed in a horizontal direction, (A) shows the process position at the time of a certain process, (B) has shown the process position in the following process of (A). . It is the figure which showed the mode of the resolution conversion process from a 8 * 8 pixel YUV420 format image to a 16 * 16 pixel YUV422 format image, and a YUV format conversion process. It is a figure which shows the characteristic part of the image processing apparatus of the 2nd Embodiment of this invention. It is a flowchart which shows the image processing method of embodiment of this invention. It is a block diagram of the conventional image processing apparatus. It is a block diagram of the conventional image processing apparatus. It is a block diagram of the conventional image processing apparatus. It is a flowchart explaining the flow of the process at the time of performing both the resolution conversion process and format conversion in the conventional image processing apparatus (the 1). It is a flowchart explaining the flow of the process at the time of performing both the resolution conversion process and format conversion in the conventional image processing apparatus (the 2). It is a figure which shows the mode of a normal resolution conversion process.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Register part 11 Setting information storage part 11a, 11b, 11c, 11d, 11e, 13a, 13b Register 12 Correction part 13 Enlargement / reduction ratio storage part

Claims (5)

In an image processing apparatus that performs resolution conversion processing and YUV format conversion processing,
Processing component that specifies YUV format information of input image, YUV format information of output image, horizontal enlargement / reduction ratio, vertical enlargement / reduction ratio, and luminance or two color difference components to be processed A setting information storage unit for storing designation information;
A correction unit that corrects the enlargement / reduction ratio in the horizontal direction or the vertical direction according to the YUV format information of the input image, the YUV format information of the output image, and the processing component designation information;
An enlargement / reduction ratio storage unit that stores the corrected enlargement / reduction ratio as a new enlargement / reduction ratio used in the resolution conversion process;
An image processing apparatus comprising:   The image processing apparatus according to claim 1, wherein the correction unit corrects the enlargement / reduction ratio by a bit shift of a predetermined bit. In an image processing apparatus that performs resolution conversion processing and YUV format conversion processing,
YUV format information of the input image, YUV format information of the output image, horizontal enlargement / reduction ratio and vertical enlargement / reduction ratio, and processing order designation information for designating the order of processing of luminance or two color difference components A setting information storage unit to store;
A processing component setting unit that sets a processing component according to the processing order designation information;
A correction unit that corrects the horizontal or vertical scaling ratio according to the YUV format information of the input image, the YUV format information of the output image, and the set processing component;
An enlargement / reduction ratio storage unit that stores the corrected enlargement / reduction ratio as a new enlargement / reduction ratio used in the resolution conversion process;
An image processing apparatus comprising:   The image processing apparatus according to claim 3, wherein the correction unit corrects the enlargement / reduction ratio by a bit shift of a predetermined bit. In an image processing method for performing resolution conversion processing and YUV format conversion processing,
Input the YUV format information of the input image, the YUV format information of the output image, the horizontal scaling factor and the vertical scaling factor,
Refer to the YUV format information of the input image and the YUV format information of the output image, and further determine a correction coefficient according to which of the three processing components consisting of luminance or two color difference components is processed,
In the correction coefficient, for each of the processing components, the input horizontal or vertical scaling ratio is corrected,
A resolution conversion process is performed using the corrected scaling ratio in the horizontal direction or the vertical direction.

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