JP4399682B2 - Image data processing apparatus and method, and recording medium - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to an image data processing apparatus and method, andrecoding mediaIn particular, when converting the number of pixels to change the size of an image to be displayed, assuming that the size of the image before conversion and the size of the image after conversion are the same, An image data processing apparatus and method for calculating pixel data after conversion based on an overlapping area ratio when overlapping, andrecoding mediaAbout.
[0002]
[Prior art]
FIG. 15 is a block diagram showing a configuration of a conventional image display system. Image data generated by the personal computer 1 is output to an LCD (Liquid Crystal Display) projector 4 via a display 2 and an image data processing device 3.
[0003]
When the number of pixels constituting the screen of the LCD projector 4 is different from the number of pixels constituting the screen of the display 2, the image data output to the LCD projector 4 is converted in number by the image data processing device 3. Projected on a screen that does not. As the pixel number conversion method of the pixel number conversion device 3, a nearest neighbor method, a bilinear method, a cubic method, or the like is used.
[0004]
Here, when the cubic method is converted from the VGA (Video Graphics Array) method having the number of pixels of 640 × 480 into the 1024 × 768 XGA (eXtended Graphics Array) method, in other words, five pixels are converted to eight pixels. A case will be described as an example.
[0005]
In the cubic system, a weighting function as shown in FIG. 16 is used, and the number of pixels is converted. In FIG. 16, it is assumed that the horizontal width of five VGA pixels and the horizontal width of eight XGA pixels are the same. When determining pixel data such as the color density of the fourth pixel of the XGA system, the maximum value of the weighting function is set so as to be positioned at the fourth pixel of the XGA system.
[0006]
For the weighting function set in this way, by performing the convolution operation using the numerical value at the intersection of the vertical line and the weighting function from each of the five VGA pixels, the XGA method Data for the fourth pixel is determined.
[0007]
[Problems to be solved by the invention]
In the above-described cubic conversion method such as the cubic method, when converting from the original pixel arrangement to the target pixel arrangement, one pixel data is determined in order to determine a plurality of pixels. For an image whose density changes sharply, the character may be blurred or deformed due to the influence of unrelated pixels.
[0008]
The present invention has been made in view of such a situation, and when converting the number of pixels, shared image information with a plurality of pixels before conversion related to the pixel of interest after conversion, for example, Thus, the area ratio is taken into consideration, so that images such as characters can be converted neatly.
[0009]
[Means for Solving the Problems]
  The image data processing apparatus according to claim 1, wherein the first storage unit that stores the input pixel data of the first image, and the first image and the second image are overlapped on a screen having an equal size. In this case, the coefficient is determined by the area ratio of the portion of each pixel of the first image that overlaps the target pixel of the second image, and the pixel data of the target pixel is obtained in a predetermined order. When the second storage means for storing a coefficient that is output and multiplied by each pixel of the first image that overlaps the target pixel, and the first image and the second image are overlapped on a screen of equal size To the pixel data of the pixel of the first image that overlaps the target pixel., In the order of pixel arrangementRead from first storage meansdo it,Arrangement pattern of pixels of the first image that overlap with the target pixelAccordingly, the pixel arrangement of the first image when the arrangement of the pixels on the first image overlapping the target pixel is changed to the first direction or the second direction perpendicular to the first direction. In order, the pixel data of the pixels of the read first imageArithmetic processing for calculating pixel data of the pixel of interest using the output means for rearranging and outputting, the coefficient output from the second storage means, and the pixel data of the pixel of the first image output by the output means Means.
[0012]
  Said output meansDivides the second image into blocks each having a predetermined number of pixels, and each block corresponds to a pixel position of the second image.Output pixel data of pixels of the first imagebe able to.
[0013]
  Said computing meansObtained by the operationSaid second imageDisplayDisplay means can be further included.
[0014]
  The image data processing method according to claim 4, wherein the first storage step of storing the input pixel data of the first image in the first storage means is equal to the first image and the second image. When determining the pixel data of the pixel of interest, which is a coefficient determined by the area ratio of the portion of each pixel of the first image that overlaps the pixel of interest of the second image when overlaid on the screen of the size, A second storage step for storing in the second storage means a coefficient that is output in a predetermined order and is multiplied by each pixel of the first image that overlaps the target pixel; and the first image and the second When the image is superimposed on the screen of the same size, the pixel data of the pixel of the first image that overlaps the target pixel is obtained., In the order of pixel arrangementRead from first storage meansdo it,Arrangement pattern of pixels of the first image that overlap with the target pixelAccordingly, the pixel arrangement of the first image when the arrangement of the pixels on the first image overlapping the target pixel is changed to the first direction or the second direction perpendicular to the first direction. In order, the pixel data of the pixels of the read first imageThe pixel data of the pixel of interest is calculated using the output step of rearranging and outputting, the coefficient output from the second storage means, and the pixel data of the pixel of the first image output by the processing of the output step And a calculation step.
[0015]
  According to a fifth aspect of the present invention, there is provided a recording medium including a first storage step of storing pixel data of an input first image in a first storage unit, a first image, and a second image in the image data processing device. This is a coefficient determined by the area ratio of the portion of each pixel of the first image that overlaps the target pixel of the second image when the image is overlapped on a screen of equal size, and the pixel data of the target pixel is A second storage step for storing, in the second storage means, a coefficient that is output in a predetermined order and multiplied by each pixel of the first image that overlaps the pixel of interest; And the second image are superimposed on a screen of the same size, the pixel data of the pixel of the first image that overlaps the target pixel is obtained., In the order of pixel arrangementRead from first storage meansdo it,Arrangement pattern of pixels of the first image that overlap with the target pixelAccordingly, the pixel arrangement of the first image when the arrangement of the pixels on the first image overlapping the target pixel is changed to the first direction or the second direction perpendicular to the first direction. In order, the pixel data of the pixels of the read first imageThe pixel data of the pixel of interest is calculated using the output step of rearranging and outputting, the coefficient output from the second storage means, and the pixel data of the pixel of the first image output by the processing of the output step And a computer-readable program for executing a process including a calculation step.
[0016]
  In the image data processing device according to claim 1, the image data processing method according to claim 4, and the recording medium according to claim 5, the pixel data of the input first image is stored, and the first When the image and the second image are overlapped on a screen of the same size, the coefficient is determined by the area ratio of the portion of each pixel of the first image that overlaps the target pixel of the second image, When obtaining pixel data of the pixel of interest, a coefficient that is output in a predetermined order and multiplied by each pixel of the first image that overlaps the pixel of interest is stored, and the first image and the second image are stored. The pixel data of the pixel of the first image that overlaps the target pixel when overlapped on the screen of equal size, In the order of pixel arrangementRead outAndArrangement pattern of pixels of the first image that overlap with the target pixelAccordingly, the pixel arrangement of the first image when the arrangement of the pixels on the first image overlapping the target pixel is changed to the first direction or the second direction perpendicular to the first direction. In order, the pixel data of the pixels of the read first image issortIsThe pixel data of the pixel of interest is calculated using the output coefficient and the pixel data of the pixel of the first image.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below, but in order to clarify the correspondence between each means of the invention described in the claims and the following embodiments, in parentheses after each means, The features of the present invention will be described with the corresponding embodiment (however, an example) added. However, of course, this description does not mean that each means is limited to the description.
[0018]
  The image data processing apparatus according to claim 1 includes a first storage unit (for example, the frame memory 22 in FIG. 2) that stores the input pixel data of the first image, the first image, and the second image data. This is a coefficient determined by the area ratio of the portion of each pixel of the first image that overlaps the target pixel of the second image when the image is overlapped on a screen of equal size, and the pixel data of the target pixel is When obtaining the second storage means (for example, the calculation coefficient selection unit 28 in FIG. 2) that stores a coefficient that is output in a predetermined order and is multiplied by each pixel of the first image that overlaps the target pixel. When the first image and the second image are superimposed on a screen having the same size, the pixel data of the pixel of the first image that overlaps the target pixel is obtained., In the order of pixel arrangementRead from first storage meansdo it,Arrangement pattern of pixels of the first image that overlap with the target pixelAccordingly, the pixel arrangement of the first image when the arrangement of the pixels on the first image overlapping the target pixel is changed to the first direction or the second direction perpendicular to the first direction. In order, the pixel data of the pixels of the read first imageOutput means for rearranging and outputting (for example, the calculation data selection unit 23 in FIG. 2), the coefficient output from the second storage means, and the pixel data of the pixels of the first image output by the output means. And a calculation means (for example, the calculation unit 24 in FIG. 2) for calculating pixel data of the target pixel.
[0019]
FIG. 1 shows a configuration of an embodiment of an image display system to which the present invention is applied. The image data generated by the personal computer 1 is output to the display 2 and the pixel number conversion device 10. The image data input to the pixel number conversion device 10 is changed to the number of pixels that is in the LCD projector 4 and is output to the LCD projector 4.
[0020]
FIG. 2 is a block diagram showing an internal configuration of the pixel number conversion apparatus 10. Image data output from the personal computer 1 is input to an A / D (Analog / Digital) converter 21. The vertical synchronization signal V1 and the horizontal synchronization signal H1 output from the personal computer 1 are input to the control signal generation unit 26 and the calculation control signal generation unit 27. Further, the control signal generation unit 26 generates a clock C1 synchronized with the input vertical synchronization signal V1 and horizontal synchronization signal H1, and supplies it to the A / D conversion unit 21.
[0021]
The A / D converter 21 converts the input analog image data into digital image data based on the clock C 1 and outputs the digital image data to the frame memory 22. Of course, when the personal computer 1 outputs digital image data, it is directly supplied to the frame memory 22. The frame memory 22 stores image data for one frame based on the control signal generated by the control signal generator 26.
[0022]
The calculation control signal generator 27 generates a new vertical synchronization signal V2 and horizontal synchronization signal H2 in synchronization with the input vertical synchronization signal V1 and horizontal synchronization signal H1, and further generates an address generated based on the calculation data The data is output to the selection unit 23. The calculation data selection unit 23 reads out pixel data necessary for calculation from the image data stored in the frame memory 22 based on the input vertical synchronization signal V2 and horizontal synchronization signal H2, and outputs the pixel data to the calculation unit 24. .
[0023]
The calculation data selection unit 23 holds a table of patterns used when converting the number of pixels, selects a pattern corresponding to the pixel data read from the frame memory 22, and uses the selected pattern data as a calculation coefficient. The data is output to the selection unit 28. The calculation coefficient selection unit 28 selects a calculation coefficient necessary for pixel number conversion corresponding to the pattern data output from the calculation data selection unit 23 and outputs the calculation coefficient to the calculation unit 24.
[0024]
The calculation unit 24 calculates new (converted) pixel data using the calculation coefficient output from the calculation coefficient selection unit 28 and the pixel data output from the calculation data selection unit 23, and performs D / A conversion. To the unit 25.
[0025]
The D / A converter 25 converts the digital image data that has been arithmetically processed by the arithmetic unit 24 and output the analog image data, and outputs the analog image data to the LCD projector 4. In this way, calculation processing is performed for each pixel, and the number of pixels constituting one screen is output by being repeated.
[0026]
Next, the pixel number conversion process performed by the pixel number conversion apparatus 10 will be described. First, the enlargement ratio and reduction ratio due to the difference between the input method and the output method will be described with reference to FIG. The format of the signal input to the pixel number conversion device 10 and the format of the output signal include VGA (Video Graphics Array), SVGA (Super VGA), XGA (eXended Graphics Array), SXGA (Super XGA), and There is UXGA (Ultra XGA).
[0027]
In FIG. 3, the input method is shown vertically, the output method is shown horizontally, and the ratio of the number of pixels of the input method to the number of pixels of the output method is shown where each input method and the output method intersect. The numerical value below it represents the ratio (number of output pixels / number of input pixels) (represented by rounding off the second decimal place). For example, when the input method is the VGA method and the output method is the XGA method, the number of pixel data M of the first image (VGA image)₁× N₁Corresponds to 640 × 480, and the number M of pixel data of the second image (XGA image)₂× N₂Corresponds to 1024 × 768. The ratio of the number of pixels of the input method and the number of pixels of the output method is 5: 8, and the ratio is 1.6. This ratio means that the number of input pixels is 1.6 times the number of pixels, that is, enlargement.
[0028]
In the VGA method, SVGA method, XGA method, and UXGA method, the number of horizontal pixels is 4 to 3, while the SXGA method is 5 to 4. Therefore, when converting to the SXGA system or converting from the SXGA system, the enlargement ratio or the reduction ratio differs depending on whether the number of horizontal pixels is the reference or the number of vertical pixels. In consideration of this, the calculation related to the SVGA method in the table shown in FIG. 3 describes values when the calculation is performed based on the number of horizontal pixels.
[0029]
Hereinafter, the pixel number conversion process will be described by taking as an example a case where the input method is the VGA method and the output method is the XGA method. As shown in FIG. 3, the number of pixels of the input method is 5: 8, and this pixel number conversion processing is performed as shown in FIG._{m, n}A block of 5 × 5 pixels (hereinafter referred to as an image block) composed of (m, n = 1 to 5) is referred to as a pixel y._{v, w}This is a process for making an 8 × 8 image block consisting of (v, w = 1 to 8). Considering this, one screen of the display format using the VGA method is composed of 128 5 × 5 image blocks in the horizontal direction and 96 in the vertical direction. Similarly, one screen of a display format using the XGA system is composed of 128 8 × 8 image blocks in the horizontal direction and 96 in the vertical direction.
[0030]
Therefore, if a VGA type 5 × 5 pixel image block is converted into an XGA type 8 × 8 pixel image block and such conversion is repeated 128 times in the horizontal direction and 96 times in the vertical direction, The conversion will end. In the following description, it is assumed that a VGA type 5 × 5 pixel image block is converted into an XGA type 8 × 8 pixel image block. Further, it is assumed that the area of the 5 × 5 pixel image block and the area of the 8 × 8 pixel image block are the same size.
[0031]
FIG. 5 is a diagram in which the 5 × 5 pixel image block of FIG. 4 and the 8 × 8 image block are overlaid. VGA pixel x_1,1XGA pixel y_1,1, Y_1,2, Y_2,1And y_2,2Pixel x_1,2Is the pixel y_1,2, Y_1,3, Y_1,4, Y_2,2, Y_2,3And y_2,4It overlaps with. Similarly, other x_{m, n}And multiple y_{V, W}It overlaps with.
[0032]
Further, referring to FIG. 6, the pixel x_1,1Is 100% (1) pixel y_1,1, 60% (0.6) pixels y_1,2And y_2,1, And 36% (0.36) pixels y_2,2It is composed of Similarly, pixel x_1,2Is 40% pixel y_1,2, 100% pixel y_1,3, 20% pixel y_1,424% pixel y_2,2, 60% pixel y_2,3, And 12% pixel y_2,4It is composed of Another pixel x_{m, n}A plurality of pixels y_{v, w}And its pixel y_{v, w}This ratio depends on the position of the pixel.
[0033]
In the above description, the pixel x_{m, n}Is pixel y_{v, w}On the contrary, the pixel y_{v, w}Is pixel x_{m, n}The following explanation will be given assuming that the system is composed of: Pixel y_1,1Is the pixel x_1,1Pixel y_1,2Is 60% pixel x_1,140% are pixels x_1,2It consists of Pixel y_2,2Is 36% pixel x_1,1, 24% are pixels x_1,2And x_2,1, The remaining 16% is pixel x_2,2It is composed of Other pixel y_{v, w}1 to 4 pixels x_{m, n}And its pixel x_{m, n}This ratio depends on the position of the pixel. When this ratio is classified, it can be seen that there are six types of patterns as shown in FIG.
[0034]
First, pattern A has one pixel y_{v, w}Is one pixel x_{m, n}It is shown that it is composed of. Pattern B is one pixel y_{v, w}Is two adjacent pixels x_{m, n}, X_{m, n + 1}It consists of and. Note that two adjacent pixels x_{m, n}, X_{m, n + 1}However, there may be a combination of upper and lower pixels. That is, in FIG. 7, 0.6 is arranged on the left side and 0.4 on the right side, but conversely, the pattern B is also set to 0.4 on the left side and 0.6 on the right side. Further, when the upper side is 0.6 and the lower side is 0.4, the pattern B is also set when the upper side is 0.4 and the lower side is 0.6. The other patterns C to F are also considered as the same pattern in the left and right, top and bottom, and interchanged patterns. Note that numbers such as 0.6 and 0.4 are coefficients used when the calculation unit 24 calculates, and are hereinafter referred to as calculation coefficients.
[0035]
In this way, when the XGA image block is rewritten using the patterns A to F, the result is as shown in FIG. An XGA image block has a combination of patterns in any of the first to fourth quadrants. The calculation data selection unit 23 includes all pattern data Y in the first to fourth quadrants._1,1To Y_8,8(This table data and data y_{v, w}To distinguish Y_{v, w}Is stored in the table, and the calculation coefficient selection unit 28 stores only the six patterns of calculation coefficients shown in FIG.
[0036]
Next, the operation of the pixel number conversion apparatus 10 shown in FIG. 2 will be described with reference to the flowchart of FIG. First, in step S1, image data, a vertical synchronization signal V1, and a horizontal synchronization signal H1 are input from the personal computer 1 to the pixel number conversion device 10. The vertical synchronization signal V1 and the horizontal synchronization signal H1 input to the pixel number conversion device 10 are input to the control signal generator 26. The control signal generator 26 generates a clock C1 synchronized with the input vertical synchronization signal V1 and horizontal synchronization signal H1.
[0037]
The clock C1 generated by the control signal generator 26 is input to the A / D converter 21 together with the image data input to the pixel number conversion device 10. In addition, the vertical synchronization signal V1 and the horizontal synchronization signal H1 are also input to the arithmetic control signal generator 27.
[0038]
In step S <b> 2, the image data input to the A / D conversion unit 21 is converted into digital image data, output to the frame memory 22, and stored. Each pixel is arranged in the frame memory 22 as in the display state. Then, the position of the pixel in the image can be easily determined based on the address given to each pixel.
[0039]
In this manner, the control signal generator 26 generates a control signal using the input vertical synchronization signal V1, horizontal synchronization signal H1, and clock C1 so as to store the image data in the frame memory 22, and the frame memory The image data recording operation 22 is controlled.
[0040]
In step S3, the arithmetic control signal generation unit 27 generates a vertical synchronization signal V2 and a horizontal synchronization signal H2 of a new image signal in synchronization with the input vertical synchronization signal V1 and horizontal synchronization signal H1. Then, the calculation control signal generator 27 generates an address y of a pixel to be calculated (pixel to be converted) based on the generated signal._{v ' , w '}(V '= 1 to 768, w' = 1 to 1024). The generated address is output to the calculation data selection unit 23.
[0041]
The calculation data selection unit 23 receives the input address y in step S4._{v ' w '}Is Y shown in FIG._1,1To Y_8,8It is determined which pixel corresponds to the pixel. This determination is performed by dividing v ′ and w ′ by 8 and obtaining the remainder. The address y_2,2, Y_1,1024, And y_322,324The determination process will be described by taking these three points as an example.
[0042]
Address y_2,2V ′ = 2 and w ′ = 2. As a result of dividing by 8, both of the remainders are 2. From this result, address y_2,2Is the Y of the image block_2,2It is determined that it corresponds to. Similarly, the address y_1,1024Since v '= 1 and w' = 1024, the remainder after division by 8 is 1 for v 'and 0 for w'. In this case, the address y_1,1024Is the Y of the image block_1,0However, for an 8 × 8 image block, Y_1,0Does not exist. In order to eliminate such inconvenience, when the remainder is 0, it is set to 8. By negotiating in this way, the address y_1,1024Is the Y of the image block_1,8It is determined that it corresponds to.
[0043]
Further address y_322,324Similarly, when dividing by 8 and obtaining the remainder, the remainder of v 'is 2 and the remainder of w' is 4. From this result, address y_322,324Is the Y of the image block_2,4It is determined that it corresponds to.
[0044]
In this way, the operation data selection unit 23 receives the input address y_{v ' , w '}Pixel Y of the image block corresponding to_{v, w}Is determined, the process proceeds to step S5. In step S5, the calculation data selection unit 23 determines the pixel Y of the determined image block._{v, w}Which pattern A to F shown in FIG. 7 corresponds to. For example, the address y described above_2,2, Y_1,1024, And y_322,324Is Y for each image block_2,2, Y_1,8, And Y_2,4Therefore, the patterns are determined as pattern D, pattern A, and pattern E, respectively, with reference to FIG.
[0045]
In this way, the calculation data selection unit 23 determines the pattern and reads out from the frame memory 22 the image data necessary for calculating the image data of the pixel. Then, while the image data is read, the calculation data selection unit 23 outputs the determined pattern to the calculation coefficient selection unit 28 in step S6, selects the calculation coefficient corresponding thereto, and calculates the calculation unit. 24.
[0046]
In step S <b> 7, the calculation data selection unit 23 outputs the image data read in step S <b> 5 to the calculation unit 24. At that time, the arrangement (output order) of the image data is changed in accordance with the arrangement of the calculation coefficients output to the calculation unit 24 by the calculation coefficient selection unit 28 and output. In step S8, the calculation unit 24 calculates XGA pixel data using the input image data and calculation coefficients.
[0047]
The processing from steps S5 to S8 is performed with the address y generated by the arithmetic control signal generator 27._2,2, Y_1,1024And y_322,324Will be described as an example. First address y_2,2From FIG. 6, pixel x_1,1, X_1,2, X_2,1,And x_2,2It can be seen that Accordingly, in step S5, the pixel data read from the frame memory 22 is x_1,1, X_1,2, X_2,1,And x_2,2It is data of. Pixel data necessary for these calculations is read from the frame memory 22 in the order of upper right, lower left, and lower right in order from the pixel existing in the upper left on the screen.
[0048]
Address y_2,2Is Y in the first quadrant of the image block, as described above._2,2Therefore, in step S6, the calculation coefficient selection unit 28 selects the calculation coefficient of the pattern D and outputs it to the calculation unit 24.
[0049]
That is, 0.36, 0.24, 0.24, and 0.16 are selected and output as calculation coefficients. These calculation coefficients are stored in the calculation coefficient selection unit 28 in this order. That is, with the pattern shown in FIG. 7, the coefficients are stored in the order of upper left, upper right, lower left, and lower right. The calculation coefficients are described below in the order recorded in parentheses for each pattern.
[0050]
Pattern A (1)
Pattern B (0.6, 0.4)
Pattern C (0.8, 0.2)
Pattern D (0.36, 0.24, 0.24, 0.16)
Pattern E (0.48, 0.12, 0.32, 0.08)
Pattern F (0.64, 0.16, 0.16, 0.04)
In step S7, the pixel data x read to the calculation data selection unit 23_1,1, X_1,2, X_2,1,And x_2,2Are rearranged into a data array suitable for the calculation performed by the calculation unit 24. In this case, since the coefficient array and the pixel data array are the same array, that is, the upper left, upper right, lower left, and lower right arrays, there is no need to rearrange them._2,2The pixel data is calculated.
[0051]
y_2,2= 0.36 × x_1,1+ 0.24 × x_1,2
+ 0.24 × x_2,1+ 0.16 × x_2,2
Next, the address generated in step S3 is y_1,1024The case of will be described. Address y_1,1024In step S4, y in the image block_1,8And a pattern A is determined. Accordingly, in step S5, one pixel data x is read from the frame memory 22._1,640In step S6, (1) is read from the calculation coefficient selector 28 as a calculation coefficient.
[0052]
In step S7, the arrangement of the pixel data is changed. In this case, however, there is only one piece of pixel data and calculation coefficient, so there is no need to change the arrangement. Accordingly, the pixel data read from the frame memory 22 is output to the calculation unit 24 as it is. And the calculating part 24 calculates pixel data based on following Formula.
[0053]
y_1,1024= 1 x_1,640
Next, the address generated in step S3 is y_322,324The case of will be described. Address y_322,324In step S4, Y in the image block_2,4And the pattern E is determined. Accordingly, in step S5, the four pixel data x are read from the frame memory 22._201,202, X_201,203, X_202,202And x_202,203Are read in this order. In step S6, (0.48, 0.12, 0.32, 0.08) is read from the calculation coefficient selection unit 28 as the calculation coefficient.
[0054]
In step S7, the arrangement of the pixel data is changed. In this case, y in FIG._2,4As can be seen from a comparison with the pattern E in FIG. Therefore, it is necessary to change the arrangement of the pixel data read from the frame memory 22 so that the left-right relationship is reversed and to output it to the calculation unit 24. That is, pixel data x_201,203, X_201,202, X_202,203And x_202,202Output in this order. By outputting the pixel data in this way, the calculation unit 24 calculates the address y based on the following equation._322,324Can be calculated.
[0055]
y_322,324= 0.48 × x_201,203+ 0.12 × x_201,202+ 0.32 × x_202,203+ 0.08 × x_202,202
Returning to the flowchart of FIG. 9, when the calculation in the calculation unit 24 is completed as described above, the process proceeds to step S9. In step S <b> 9, the calculation unit 24 outputs the calculated pixel data to the D / A conversion unit 25. The D / A converter 25 converts the input digital pixel data into analog pixel data and outputs the analog pixel data to the LCD projector 4.
[0056]
In step S10, it is determined whether or not the pixel number conversion operation is finished. In other words, this process is a determination as to whether or not all the pixel data stored in the frame memory 22 has been read. If it is determined that all the pixel data has been read, the process of this flowchart is terminated. If it is determined that all the pixel data has not been read, the process returns to step S3 and the subsequent processes are repeated. .
[0057]
Next, a case where a reduction process is performed will be described. Here, the case of converting from the XGA system to the VGA system will be described as an example. In this case, an 8 × 8 pixel image block is converted to a 5 × 5 pixel image block. Therefore, the reduction ratio is 0.6 times from FIG.
[0058]
As already explained in FIG. 5, the pixel x_1,1Is the pixel y_1,1, Y_1,2, Y_2,1,And y_2,2It consists of and. Here, pixel x_1,1And x_1,2As an example, the ratio of the components will be described with reference to FIG. First, pixel x_1,140% (0.4) of the pixel y_1,1, 23% (0.23) each is pixel y_1,2And y_2,1, And 14% (0.14) are pixels y_2,2It is composed of Pixel x_1,2Is 15% pixel y_1,240% is pixel y_1,38% is pixel y_1,49% is pixel y_2,2, 23%_2,3, And 5%_2,4It is composed of
[0059]
Similarly, other x_{m, n}And multiple y_{v, w}That y_{v, w}This ratio depends on the position of the pixel. When this ratio is classified, it can be seen that there are six types of patterns a to f as shown in FIG.
[0060]
First, the pattern a has one pixel x_{m, n}Is described with reference to the upper left pixel, the four pixels y_{v, w}, Y_{v, w + 1}, Y_{v + 1, w}And y_{v + 1, w + 1}It is shown that it is composed of. In FIG. 11, 0.4 is arranged on the upper left side, 0.23 on the upper right side, 0.23 on the lower right side, and 0.14 on the lower left side. And The other patterns b to f are also considered as the same pattern when the left and right and top and bottom positions are switched.
[0061]
When the VGA 5 × 5 image block is rewritten using the patterns a to f set in this way, the result is as shown in FIG. The pattern table is stored in the calculation data selection unit 23. In addition, the calculation coefficient of each pattern illustrated in FIG. 11 is stored in the calculation coefficient selection unit 28.
[0062]
The operation of the pixel number conversion apparatus 10 in the case of reduction follows the flowchart of FIG. 9 as in the case of enlargement. Therefore, the explanation is omitted, and only the method of calculation is shown below.
[0063]
The array of operation coefficients stored in the operation coefficient selection unit 28 is as shown below, and this array is determined according to the pattern shown in FIG.
[0064]
Pattern a (0.4, 0.23, 0.23, 0.14)
Pattern b (0.15, 0.4, 0.08, 0.09, 0.23, 0, 05)
Pattern c (0.31, 0.31, 0.19, 0.19)
Pattern d (0.06, 0.15, 0.03, 0.15, 0.4, 0.08, 0.03, 0.08, 0.02)
Pattern e (0.13, 0.13, 0.31, 0.31, 0.06, 0.06)
Pattern f (0.25, 0.25, 0.25, 0.25)
The address generated in step S3 in the flowchart of FIG._{m ' , n '}(M ′ = 1 to 480, n ′ = 1 to 640). The determination of the corresponding pixel in the image block performed in step S4 is performed by dividing m ′ and n ′ by 5 and obtaining the remainder. As explained in the enlargement, when the remainder is 0, 0 is not used and 5 is set. For example, the address is x_1,1In this case, m ′ = 1 and n ′ = 1, and when dividing by 5, the remainder becomes 1, respectively. Therefore, the address x_1,1Is the X in the pixel block_1,1It is judged that it corresponds to. The pattern is determined as pattern a.
[0065]
The address is x_480,640In this case, m ′ = 480 and n ′ = 640, and when dividing by 5, the remainder becomes 0 respectively. Therefore, the address x_480,640Is the X in the pixel block_5,5It is judged that it corresponds to. The pattern is determined as pattern a.
[0066]
When the corresponding pixels in the image block are determined in this way and the pattern is determined, image data is read in step S5. For example, the above address is x_{1, 1}And x_{480, 640}In this case, since both are determined to be pattern a, image data for four pixels is read out. That is, address x_{1, 1}The pixel y_1,1, Y_1,2, Y_2,1And y_2,2Are read in this order. Address x_{480, 640}If y_767,1023, Y_767,1024, Y_768,1023, And y_768,1024Are read in this order.
[0067]
Address x_{1, 1}And x_{480, 640}Are determined to be the pattern a, the calculation coefficients selected by the calculation coefficient selection unit 28 in step S6 and output to the calculation unit 24 are (0.4, 0.23, 0.23, 0.14).
[0068]
In step S7, the arrangement of the pixel data is changed. In this case, address X_{1, 1}Since the arrangement of the read pixel data and the arrangement of the operation coefficients are the same, there is no need to change the arrangement. Therefore, the calculation data selection unit 23 outputs the pixel data read from the frame memory 22 to the calculation unit 24 in the arrangement. By outputting in this way, the calculation unit 24 calculates new pixel data as shown in the following equation.
[0069]
x_1,1= 0.4 × y_1,1+ 0.23 × y_1,2+ 0.23 × y_2,1+ 0.14 × y_2,2
However, address x_{480, 640}Is the same as the pattern a, but the array of the operation coefficients is the address x_{1, 1}It has a different arrangement and is an arrangement in which the top, bottom, left and right are interchanged. In this case, since the arrangement of the calculation coefficients is fixed, it is necessary to change the arrangement of the pixel data read from the frame memory 22 and output it to the calculation unit 24. That is, the calculation data selection unit 23 displays the array y of read pixel data._767,1023, Y_767,1024, Y_768,1023, And y_768,1024Y_768,1024, Y_768,1023, Y_767,1024And y_767,1023To the arithmetic unit 24. By outputting in this way, the calculation unit 24 calculates new pixel data as shown in the following equation.
[0070]
x_{480, 640}= 0.4 × y_768,1024+ 0.23 × y_768,1023+ 0.23 × y_767,1024+ 0.14 × y_767,1023
In this way, when the image is enlarged or reduced by converting the number of pixels, by changing the calculation coefficient used depending on the position where the pixel exists, by calculating new pixel data, a sharp change is made. For example, a character string or the like can be converted without blurring the characters. Of course, it can also be used for an image that does not change sharply, such as a natural image.
[0071]
In the above description, the array of calculation coefficients is fixed and the pixel data read from the frame memory 22 is changed to an array suitable for the calculation and output. However, the pixel data read from the frame memory 22 is output. The array may be used as it is, and the array of calculation coefficients may be changed to an array suitable for calculation. In the above description, the VGA method and the XGA method have been described, but it goes without saying that they can be used for other methods.
[0072]
Further, the calculation coefficient recorded in the calculation coefficient selection unit 28 is not limited to the above-described value. For example, a value having a calculation coefficient of 0.1 or less may not be used. In the above description, the calculation coefficient is determined based on the area ratio. However, according to the image information, the calculation coefficient is determined using a method other than the area ratio, such as the Cubic method, in accordance with the pixel position. Also good.
[0073]
In the above description, the case where the pixel number conversion device 10 exists as a single device and supplies the converted image data to the LCD projector 4 has been described as an example. However, the present invention is not limited to this embodiment. It is not limited to. For example, as shown in FIG. 13, the LCD projector 30 includes the pixel number conversion device 10, and the output of the personal computer 1 is directly input to the LCD projector 30, processed, and the signal is displayed. May be. In such a configuration, the internal configuration of the LCD projector 30 is as shown in FIG.
[0074]
The LCD projector 30 normally includes a plurality of input terminals so that various signals such as a composite video signal, a component video signal, and an RGB signal can be input. Such an LCD projector 30 is often provided with a scan converter that performs pixel number conversion processing in order to display signals having different numbers of pixels on the LCD panel 33 having a predetermined number of pixels. The pixel number conversion device 10 is used as a scan converter.
[0075]
An image signal output from a device connected to a predetermined input terminal, for example, the personal computer 1 is input to the input signal processing unit 31 of the LCD projector 30. The input signal processing unit 31 performs processing such as video signal synchronization separation and RGB decoding from the input image signal as necessary. The horizontal synchronization signal H1, the vertical synchronization signal V1, and the RGB image data processed and output by the input signal processing unit 31 are supplied to the pixel number conversion device 10 as a scan converter. The configuration of the pixel number conversion device 10 is the same as the configuration of the pixel number conversion device 10 described above, and the operation thereof is also the same, so the description thereof is omitted.
[0076]
The image data output from the pixel number conversion device 10 is output to the driver 32. The driver 32 modulates the LCD panel 33 based on the input image data. Although not shown, image data is displayed by irradiating light from the light source onto the LCD panel 33 using optical means and projecting it onto a screen or the like. As described above, by incorporating the pixel number conversion device 10 of the present invention in the LCD projector 30, an LCD projector capable of converting the number of pixels without blurring an image that undergoes steep conversion. It can be offered at a low price.
[0077]
In addition to the LCD projector 4 (30) described above, the present invention provides a projection display device using a reflective spatial modulation element typified by a digital mirror device (DMD), a plasma display (PDP), The present invention can also be applied to a direct view display device represented by a diode (LED) display. That is, the present invention can be applied to any display device that has fixed pixels and the total number of pixels is determined.
[0078]
In this specification, the medium for providing a computer program for executing the above processing to the user includes not only an information recording medium such as a magnetic disk and a CD-ROM, but also a transmission medium via a network such as the Internet and a digital satellite. .
[0079]
【The invention's effect】
  As described above, the image data processing device according to claim 1,Claim 4And the image data processing method described in 1.Claim 5Described inAccording to the recording mediumIt is possible to perform pixel number conversion accompanying enlargement / reduction on image data that changes sharply, for example, a character string, without the image after conversion being blurred or deformed.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of an embodiment of an image display system to which an image data processing apparatus of the present invention is applied.
FIG. 2 is a block diagram showing an internal configuration of a pixel number conversion apparatus.
FIG. 3 is a diagram illustrating a pixel ratio depending on a difference between an input method and an output method.
FIG. 4 is a diagram for explaining conversion of the number of pixels when converting a VGA system to an XGA system.
FIG. 5 is a diagram when a VGA screen and an XGA screen are overlapped.
6 is an enlarged view of a part of FIG.
FIG. 7 is a diagram illustrating types of patterns.
FIG. 8 is a diagram in which XGA screens are classified according to the pattern of FIG.
FIG. 9 is a flowchart illustrating the operation of the pixel number conversion apparatus.
FIG. 10 is a diagram for explaining the conversion of the number of pixels when converting an XGA system to a VGA system.
FIG. 11 is a diagram illustrating types of patterns.
12 is a diagram in which VGA screens are classified according to the pattern of FIG.
FIG. 13 is a block diagram showing another configuration of the image display system.
14 is a block diagram showing an internal configuration of the LCD projector 30 shown in FIG.
FIG. 15 is a diagram illustrating a configuration of an example of a conventional image display system.
FIG. 16 is a diagram illustrating a cubic system.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Personal computer, 2 Display, 4 LCD projector, 10 Pixel number converter, 21 A / D conversion part, 22 Frame memory, 23 Calculation data selection part, 24 Calculation part, 25 D / A conversion part, 26 Control signal generation part , 27 Calculation control signal generator, 28 Calculation coefficient selector

Claims (5)

In an image data processing apparatus for converting a first image of M ₁ × N ₁ pixel data into a _second image of M ₂ × N ₂ pixel data,
First storage means for storing pixel data of the input first image;
When the first image and the second image are superimposed on a screen having the same size, it is determined by the area ratio of the portion of each pixel of the first image that overlaps the target pixel of the second image. A second coefficient that is output in a predetermined order and is multiplied by each pixel of the first image that overlaps the target pixel when obtaining pixel data of the target pixel. Storage means,
When the first image and the second image are overlapped on a screen having the same size, the pixel data of the pixel of the first image that overlaps the target pixel is converted to the first data in the pixel arrangement order. and read out from the storage means, wherein according to the arrangement pattern of pixels of the first image overlapping the pixel of interest, the arrangement of pixels on the first image overlapping the pixel of interest, a first direction or, Output that rearranges and outputs pixel data of the pixels of the first image in the order of arrangement of the pixels of the first image when the pixel is replaced in a second direction perpendicular to the first direction. Means,
Calculating means for calculating pixel data of the pixel of interest using the coefficient output from the second storage means and pixel data of the pixels of the first image output from the output means; An image data processing apparatus. The output means divides the second image into blocks each having a predetermined number of pixels, and outputs pixel data of pixels of the first image corresponding to pixel positions of the second image for each block. The image data processing apparatus according to claim 1. The image data processing apparatus according to claim 1, further comprising display means for displaying the second image obtained by calculation by the calculation means. In an image data processing method of an image data processing apparatus for converting a first image of M ₁ × N ₁ pixel data into a _second image of M ₂ × N ₂ pixel data,
A first storage step of storing the input pixel data of the first image in a first storage means;
When the first image and the second image are superimposed on a screen having the same size, it is determined by the area ratio of the portion of each pixel of the first image that overlaps the target pixel of the second image. A coefficient that is output in a predetermined order and is multiplied by each pixel of the first image that overlaps the pixel of interest when the pixel data of the pixel of interest is obtained. A second storage step for storing in the means;
When the first image and the second image are overlapped on a screen having the same size, the pixel data of the pixel of the first image that overlaps the target pixel is converted to the first data in the pixel arrangement order. and read out from the storage means, wherein according to the arrangement pattern of pixels of the first image overlapping the pixel of interest, the arrangement of pixels on the first image overlapping the pixel of interest, a first direction or, Output that rearranges and outputs pixel data of the pixels of the first image in the order of arrangement of the pixels of the first image when the pixel is replaced in a second direction perpendicular to the first direction. Steps,
A calculation step of calculating pixel data of the pixel of interest using the coefficient output from the second storage means and pixel data of the pixel of the first image output by the processing of the output step; An image data processing method comprising: An image data processing device that converts a first image of M ₁ × N ₁ pixel data into a _second image of M ₂ × N ₂ pixel data,
A first storage step of storing the input pixel data of the first image in a first storage means;
When the first image and the second image are superimposed on a screen having the same size, it is determined by the area ratio of the portion of each pixel of the first image that overlaps the target pixel of the second image. A coefficient that is output in a predetermined order and is multiplied by each pixel of the first image that overlaps the pixel of interest when the pixel data of the pixel of interest is obtained. A second storage step for storing in the means;
When the first image and the second image are overlapped on a screen having the same size, the pixel data of the pixel of the first image that overlaps the target pixel is converted to the first data in the pixel arrangement order. and read out from the storage means, wherein according to the arrangement pattern of pixels of the first image overlapping the pixel of interest, the arrangement of pixels on the first image overlapping the pixel of interest, a first direction or, Output that rearranges and outputs pixel data of the pixels of the first image in the order of arrangement of the pixels of the first image when the pixel is replaced in a second direction perpendicular to the first direction. Steps,
A calculation step of calculating pixel data of the pixel of interest using the coefficient output from the second storage means and pixel data of the pixel of the first image output by the processing of the output step; A computer-readable program for executing a process including: a recording medium comprising:

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