JP2008165538A - Image processor and control method for image processor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image processor and the control method of the image processor for reducing a mosquito noise generated in the periphery of characters when JPEG is compressed in document data in which characters are arranged in multi-layers. <P>SOLUTION: Each object in document data is converted into a picture image, and the converted picture image is compressed so that a compressed image can be generated, and only the character object is converted into the picture image, and the converted picture image is variably magnified. An outline image is extracted from the variably magnified image, and a mask image is generated based on the extracted outline image, and the compressed image is extended, and the painted-out color of a character and the peripheral color of a character are determined based on the extended image and the mask image. Then, the image is generated based on the extended image, the mask image, the painted-out color and the peripheral color. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

The present invention relates to an image compression apparatus that compresses an image, an image expansion apparatus that expands the image, and a printer system using them.

  In recent years, the amount of data transmitted from a host computer to a printer is increasing as the resolution and color of the printer increase. In particular, since all data is transmitted as raster data in a raster printer such as an ink jet printer, the amount of data is greatly increased, and it is not uncommon for the printing speed to decrease.

  In order to improve the transfer speed, a high-speed interface for connecting the host computer and the printer is adopted. However, when considering a low-speed interface, wireless connection, or the like, there is a concern about a decrease in printing speed.

  In order to solve this concern, a technique is known in which, instead of transmitting raster data to a printer, a compressed image by the JPEG method is generated by a host computer, decompressed by the printer, and printed. According to this technique, since the amount of data is reduced by compression, the time required for transfer is reduced.

  However, by using the JPEG method, data can be compressed, but there is a problem that mosquito noise occurs at the boundary of the character area, and there is a problem that the character color is dull. The “character color dullness” is image degradation that occurs in the edge portion of the character, particularly in the character region.

  Therefore, the printer driver generates edge information including the start point, end point, and color information of the character region from the document data, generates an image in which the character region is filled with the same color as the region other than the character, and JPEG compression There is a known method (see, for example, Patent Document 1). At the time of data reproduction, a character data portion is generated from the edge information on the decompressed data.

Since only the same color exists in the JPEG image, no mosquito noise occurs around the character. In addition, since the color information included in the edge information can be used to fill the entire character area with the same color, there is an advantage that the dullness of the color near the boundary that occurs when JPEG compression is performed including the character portion does not occur. There is also.
JP 2006-54712 A

  However, in the above conventional example, when characters are arranged in one layer, mosquito noise and color dullness can be suppressed, but when characters and characters of different colors are arranged in multiple layers. There is a problem that mosquito noise and color dullness cannot be suppressed.

  In other words, in the above conventional example, since the color to be adopted cannot be determined in the background corresponding to the character portion, it is not sufficient to suppress the occurrence of mosquito noise, and thereby a good result can be obtained when restoring the document data. There is a problem that you can not.

  It is an object of the present invention to provide an image processing apparatus and a control method for the image processing apparatus that can reduce mosquito noise generated around the characters in JPEG compression in document data in which characters are arranged in multiple layers. To do.

Another object of the present invention is to provide an image processing apparatus and a control method for the image processing apparatus that can suppress the dullness of the character color that occurs at the boundary portion and can generate a good restored image.

The present invention includes a first conversion unit that converts each object in the document data into an image, and a compressed image generation unit that generates a compressed image by compressing the image image converted by the first conversion unit. Have. According to the present invention, a second conversion unit that converts only a text object into an image, an image scaling unit that scales an image image converted by the second conversion unit, and the image scaling unit scales the image. Outline image extraction means for extracting an outline image from the image. The present invention further includes a mask image generating unit that generates a mask image based on the extracted outline image, and an image expansion unit that expands the compressed image. The present invention provides color determining means for determining a fill color of a character and a surrounding color of the character based on the expanded image and the mask image, the expanded image, the mask image, and the fill image. Image generation means for generating an image based on the color and the peripheral color.

According to the present invention, it is possible to reduce mosquito noise generated around characters in JPEG compression in document data in which characters are arranged in multiple layers.

  The best mode for carrying out the invention is the following embodiment.

  FIG. 1 is a schematic perspective view of a printer apparatus 100 that is Embodiment 1 of the present invention.

  The printer apparatus 100 is an example of an image processing apparatus, and has a function as a normal PC printer that receives data from a host computer (PC) and prints it.

  The printer device 100 has a function of directly reading and printing image data stored in a storage medium such as a memory card, or a function of receiving and printing image data from a digital camera, a PDA, or the like. Note that the printer device 100 may be a device that exhibits a function as a scanner by using a reading unit and also functions as a copier.

  The printer apparatus 100 includes a display unit 1, an operation unit 2, a card interface 3, a reading unit 4, and a recording unit 5.

  FIG. 2 is a diagram illustrating a configuration of the printer apparatus 100.

  In addition to the members shown in FIG. 1, the printer device 100 includes a CPU 20, a ROM 21, a RAM 22, a nonvolatile RAM 23, an image processing unit 24, a driving unit 25, and a sensor unit 26.

  The CPU 20 operates by loading a program code from the ROM 21 into the RAM 22. In operation, the nonvolatile RAM 23 may operate based on previously stored setting information.

  The printer device 100 receives user input from the operation unit 2, receives image data from the card interface 3, for example, and performs image processing by the image processing unit 24, and then the recording unit 5 performs printing.

  Further, after the reading unit 4 scans an image and the image processing unit 24 performs image processing, the recording unit 5 performs printing, thereby realizing a copy function. The drive unit 25 drives the main body, and the display unit 1 is used for displaying a user interface.

  Next, the configuration of the printer system PS1 will be described.

  FIG. 3 is a block diagram showing a printer system PS1 including the printer device 100. As shown in FIG.

  The printer system PS1 includes a printer device 100, a printer control device 40, a display device 31, and an input device 32.

  The display device 31 is a device that displays an image generated by the printer control device 40. The input device 32 is a device that inputs an image to the printer control device 40.

  The printer control device 40 includes a storage area 43 therein and is connected to the display device 31 and the input device 32. The printer control device 40 is connected to the printer device 100 through a bidirectional interface. In the printer system PS1, printing data is generated in the printer control device 40, and the printer device 100 performs printing. The above is the outline of the printer system PS1.

  Next, main processes of the printer system PS1 will be described.

  FIG. 4 is a diagram illustrating an example of data to be printed by the printer system PS1.

  This data includes image, character, and graphics data.

  Next, the configuration of the printer system PS1 will be described.

  FIG. 5 is a diagram illustrating the configuration of the printer system PS1.

  The printer system PS1 includes a printer control device 40 and a printer device 100. A printer driver 41 is disposed in the printer control device 40. The printer driver 41 includes a print data acquisition unit 411, an all image data generation unit 412, a character image data generation unit 413, a compressed data generation unit 414, a mask data generation unit 415, and a data output unit 416. Further, the printer control device 40 includes a data transmission unit 42 and a storage area 43.

  The printer apparatus 100 includes a data receiving unit 51, a compressed data decoding unit 52, a mask data analysis unit 53, a fill color / peripheral color determination unit 54, a print data generation unit 55, and a data printing unit 56.

  The printer device 100 and the printer control device 40 are connected by a bidirectional interface. A printer driver 41 in the printer control device 40 converts the data shown in FIG. 4 into data to be transmitted to the printer.

  In the printer driver 41, first, the print data acquisition unit 411 acquires the print data. The all image data generation unit 412 renders the acquired data on the memory as multi-value RGB data. Among the print data, for character data, the character image data generation unit 413 renders the character data as RGB data on another memory.

  FIG. 6 is a diagram illustrating input print data and rendering results on two memories.

  FIG. 6A is a diagram showing an arbitrary input image, and FIG. 6B is a diagram showing the entire image rendering result obtained by rendering the input image as digital data on the memory, and FIG. FIG. 10 is a diagram illustrating a rendering result of only a character part.

  On the print data, there are objects such as characters, images, and graphics, and there is an overlap for each. For this reason, as shown in FIG. 6C, it is assumed that the rendering result of the character portion is only the characters visible from above. In FIG. 6C, the result is that a part of the character string is cut off by the image.

  Next, the compressed data generating unit 414 compresses all images rendered by the all image data generating unit 412, and the compressed data is stored in the storage area 43. When compressing, an irreversible compression method such as JPEG is used. This reduces the amount of data to be transferred. On the other hand, the character part image (C) generated by the character image data generation unit 413 is transferred to the mask data generation unit 415, and mask data is generated and stored in the storage area 43 by an operation described later.

  Further, the generated compressed data and mask data are read from the storage area 43, and the data output unit 416 transmits the data to the printer device 100 via the data transmission unit 42. The above is the processing in the printer control device 40.

  Next, processing of the printer apparatus 100 will be described.

  The data transmission unit 51 receives the data transmitted from the printer control device 40. Of the received data, the compressed data decoding unit 52 decodes the compressed data.

  FIG. 7 is a diagram showing the decoded result.

  Since the result of FIG. 7A is obtained by decompressing irreversibly compressed data, mosquito noise in JPEG compression and color dullness are generated around the character. Note that the mosquito noise around the character shown in FIG. 7A and the dullness of the color inside the character are shown in FIG.

  Next, the mask data analysis unit 53 analyzes the received mask data. The “mask data” is data of only a character portion as shown in FIG.

  Next, based on the data expanded by the compressed data decoding unit 52 and the analysis result by the mask data analysis unit 53, the fill color / peripheral color determination unit 54 applies the character portion and the periphery of the expanded data. Determine the color. Details of this processing will be described later.

  Based on the determined fill color and peripheral color, the data decoded by the print data generation unit 55 is overwritten, and the data printing unit 56 performs printing. FIG. 7C is a diagram illustrating a printing result. The above is the processing of the printer apparatus 100.

  Next, the processing operation of the printer apparatus 100 will be described.

  FIG. 8 is a flowchart showing the processing operation of the printer apparatus 100.

  In S0, processing in the printer control device 40 is started. In S1, all compressed data is generated. In S2, mask data is generated. In S3, both data are transmitted to the printer device. In S4, the printer apparatus receives the compressed data and the mask data, and in S5, the compressed data is decoded. In S6, the mask data is analyzed, and in S7, the fill color and the peripheral color are determined for the inside and around the character. Finally, a printing process is performed in S8, and the process ends in S9. The above is the schematic operation of this system.

  Next, the processing operation of all image data generation unit 412 to mask data generation unit 415 shown in FIG. 5 will be described in detail.

  FIG. 9 is a flowchart showing processing operations of the all-image data generation unit 412 to the mask data generation unit 415.

  In step S10, the printer driver process is started. In step S11, it is determined whether drawing of all objects has been completed. The “object” is a character, an image, graphics, or the like. If all the objects have not been drawn, the target object is obtained in S12. In S13, the target object is rendered in the memory for all images. By this processing, all data to be printed is rendered in all image memories.

  In S14, it is determined whether the target object is a character. If the target object is a character, in S15, the character is rendered in the character image memory in the same manner as the all image memory. By this processing, the character data is rendered on the character image memory.

  On the other hand, if the target object is not a character, in S16, the target object is rendered as a white area on the character image memory. With the above processing, only character data is rendered on the character image memory. Further, if another object overwrites the character part in accordance with the drawing order, a part of the character may be deleted.

  The above process is performed, and the process returns to S11. If it is determined in S11 that the generation of all objects has been completed, the contents of all the image memories are converted into JPEG data in S17. Next, in S18, mask data is generated by mask data processing to be described later. By performing the above processing, compressed print image data and mask data are created, and the processing ends.

  Next, mask data creation in S18 will be described.

  FIG. 10 is a flowchart showing the mask data creation operation in S18.

  In S20, the process is started, and in S21, data enlarged twice vertically and horizontally is generated in the character image buffer 2 different from the character image memory. When enlarging, a known simple enlargement technique is used to copy pixels vertically and horizontally.

  FIG. 11 is a diagram illustrating a simple enlargement process.

  The result of enlarging the target pixel X of an arbitrary input image (A) twice vertically and horizontally is the upper left portion shown in FIG.

  FIG. 12 is a diagram showing the original image of the character part, the result of enlarging it twice, the result of extracting the outline from this result, and the result of binarizing it.

  FIG. 12A shows the original image of the character part, and FIG. 12B shows the result of double enlargement.

  Next, outline data of the character image is extracted in the processing from S22. First, in S22, it is determined whether or not the processing of all rasters in the character image buffer 2 has been completed. If the processing has not been completed, the reference pixel is set at the left end of the target raster in S23.

  In S24, it is determined whether or not the processing of all pixels of the target raster has been completed. If not completed, it is determined in S25 whether the reference pixel is white data. If it is not a white pixel, it is determined in S26 whether the internal flag is ON. If the flag is ON, it is determined in S27 whether the reference pixel is the rightmost pixel. If it is not the right end pixel, it is determined in S28 whether or not the next pixel of the target pixel is a white pixel. If it is not a white pixel, the target pixel is overwritten with the white pixel in S29, and the process returns to S24. With the above processing, the pixels inside the character area in one raster are changed to white pixels.

  On the other hand, if it is determined in S27 that the pixel is the rightmost pixel, or if it is determined in S28 that the next pixel is a white pixel, the internal flag is changed to OFF in S30. In this case, pixel overwriting is not performed. The above processing is performed and the process returns to S24. This processing is processing at a portion other than the character on one raster or the right end pixel.

  If the flag is OFF in S26, the flag is turned ON in S31. This process is a case where the start point of the character on one raster is recognized, and the character start point pixel is not overwritten. With the above processing, only the left and right end pixels of the character portion on one raster are left, the internal pixels are overwritten with white, and only the outline portion is extracted.

  In S25, if the reference pixel is a white pixel, it is out of the character area, so the process returns to S24 without performing any processing. The above processing is repeated for all rasters.

  The result of extracting the outline shown in FIG. 12B is the diagram shown in FIG.

  Next, in S32, the contents of the character image buffer 2 are binarized. In this processing, a known binarization technique is used, but each bit is set to 0 or 1 depending on whether the target pixel is white.

  FIG. 13 is a diagram illustrating binarization processing.

  In FIG. 13, the corresponding bit is designated as 1 or 0 depending on whether the RGB value of each pixel is white. In FIG. 13, data for two pixels is given as an example, but pixel 1 shown in FIG. 13 is “1”, and pixel 2 shown in FIG. 13 is “0”. Conventionally, one pixel is represented by 24-bit RGB data, but in the binarization process, one pixel can be represented by one bit. FIG. 12D is a diagram showing a result of performing the above processing.

  Next, the extraction result of the outline part will be described.

  FIG. 14 is an enlarged view of a character image obtained by extracting an outline and an arrow portion.

  FIG. 14A is a diagram showing a character image obtained by extracting an outline, and FIG. 14B is an enlarged view of an arrow portion.

  In FIG. 14B, black pixels are pixels at the left and right ends of the character area, and gray pixels are pixels that have been replaced with white pixels by the above processing. White pixels are pixels outside the character area.

  With the above process, the process of extracting the binary outline data from the multi-value character data is completed, and the data for which this process is completed is “mask data”. That is, “mask data” is data obtained by extracting outline data represented by binary values from multi-value character data.

  Next, processing operations of the compressed data code unit 52 to the print data generation unit 55 will be described.

  FIG. 15 is a flowchart showing processing operations of the compressed data code unit 52 to the print data generation unit 55.

  In S40, processing in the printer is started. In S41, the received JPEG image data is expanded on the memory. As described above, the expanded data may have mosquito noise or color dullness near the boundary of the character portion.

  In S42, the received mask data is rendered on the memory. In S43, it is first determined whether or not the processing of all rasters of the mask data has been completed. If not, it is determined in S44 whether or not the target pixel of the mask data is a part of a character (within a character image). to decide. If it is a part of a character, a fill color is acquired by means described later in S45.

  In S46, the target pixel of the JPEG image relative to the referenced mask data pixel is output as a fill color to the buffer 2, and the process returns to S43. If it is determined in S44 that the image is outside the character image, it is determined in S47 whether the target pixel is a peripheral pixel of the character. This determination process will also be described in detail later.

  If it is determined in S47 that the pixel is a peripheral pixel, a peripheral color is acquired by means described later in S48. In S49, the target pixel of the JPEG image relative to the mask data pixel being referred to is set as the peripheral color, and is output to the buffer 2, and the process returns to S43.

  If it is determined in S47 that the pixel is not a peripheral pixel of the character, the target pixel of the JPEG image relative to the mask data pixel is copied to the buffer 2 in S50, and the process returns to S43 to complete the processing of all rasters. Steps S43 to S50 are repeated. If all rasters have been processed, the contents of buffer 2 are printed in S51, and the process ends. The above is the main operation in the printer.

  Next, a method for determining the fill color will be described.

  FIG. 16 shows outline mask data of the upper part of the character A, and one square shows one MCU of the corresponding JPEG image.

  The “1 MCU” is composed of, for example, 8 × 8 pixels. As described above, the mask data is enlarged twice as much as the original size (1 pixel is 4 pixels). In order to clarify the comparison with the original JPEG image, the mask data is 4 pixels in FIG. Is expressed as one pixel. Moreover, although (1) and (2) shown in FIG. 16 both represent MCUs located in the character area, they are also used to mean that the target pixel is an arbitrary pixel in this MCU.

  FIG. 17 is a flowchart illustrating processing for determining a fill color in the first embodiment.

  First, in FIG. 17, in S61, the MCU containing the target pixel (hereinafter referred to as “target MCU”) is determined. Although (1) and (2) shown in FIG. 16 are MCUs containing the target pixel, the determination of the MCU is to find a pixel on the JPEG image corresponding to the target pixel and is easily determined. be able to.

  Next, in S62, surrounding MCUs with which the target MCU is in contact (hereinafter referred to as “surrounding MCUs”) are determined. A black or gray MCU adjacent to each of (1) and (2) shown in FIG. 16 is the target MCU.

  Next, in S63, it is determined whether all the pixels included in the target MCU and the surrounding MCU are present in the character area. If all are present (in the case of (1) shown in FIG. 16), it is determined in S64 that a fill color is given to the target pixel. If it is determined in S63 that some of the MCUs include pixels outside the character area (in the case of (2) shown in FIG. 16), MCUs including pixels outside the character area are detected in S65. The average value of all pixels in the surrounding MCU excluding (in FIG. 16, gray MCU) is obtained.

  In S66, the average value is determined as a fill color. 16 is a black MCU around (2) shown in FIG. 16 plus (2) itself shown in FIG. The above is the method for determining the fill color. By the above process, the accuracy of the fill color determination is improved by utilizing the characteristic of the MCU that the dullness of the color is closed in the MCU. In the JPEG compression method, encoding is performed for each MCU block, so that the influence of pixels included in other MCUs does not affect at the time of encoding.

  Next, a method for determining the peripheral color in the first embodiment will be described.

  FIG. 18 is a diagram showing outline mask data of the upper part of the character A.

  In FIG. 18, one square is one MCU of a corresponding JPEG image, and one MCU is composed of, for example, 8 × 8 pixels. As described above, the mask data is enlarged twice as much as the original size (1 pixel is 4 pixels), but in order to clarify the comparison with the original JPEG image, the mask data is 4 pixels in FIG. Is expressed as one pixel.

  Further, both (1) and (2) shown in FIG. 18 represent MCUs located in the character area, but they are also used to mean that the target pixel is any one pixel in this MCU. .

  FIG. 19 is a flowchart illustrating processing for determining a peripheral color in the first embodiment.

  First, in S71, the MCU containing the pixel of interest (hereinafter referred to as “target MCU”) is determined. In FIG. 18, (1) and (2) are MCUs containing the target pixel. When determining the MCU, the MCU is easily determined by finding the pixel on the JPEG image corresponding to the target pixel. can do.

  Next, in S72, peripheral MCUs with which the target MCU is in contact (hereinafter referred to as “surrounding MCUs”) are determined. The black or gray MCU adjacent to (1) and (2) in FIG. 18 is the surrounding MCU.

  Next, in S73, it is determined whether or not all the pixels included in the MCU among the surrounding MCUs are MCUs that exist outside the character area. In FIG. 18, the black MCU is the target. If there is a target peripheral MCU (black MCU), in S74, an average value of pixels outside the character area existing in those peripheral MCUs (black MCU) is obtained (average value of all pixels of all black MCUs). Seeking). The above “average pixel value” is a value obtained by calculating the average of the YCbCr values of the respective pixels, and can be determined by Y = (Y1 + Y2 +... + Yn) / n. The same applies to the Cb and Cr values.

  In S75, the difference between each pixel of MCU (1) or MCU (2) and the average value is obtained. In S76, it is determined whether or not there is at least one pixel whose difference exceeds a predetermined threshold value. If there is one, in S77, the color of the pixel of interest is set as the peripheral color for that pixel. That is, even if the pixel of interest is replaced with a peripheral color, the pixel is replaced with the same color. In other words, the color of the target pixel is not changed.

  On the other hand, if the difference between all the pixels is within the threshold value, in S78, whether or not all the pixels in the surrounding MCU not including the character area are the same color (whether the color difference of each pixel is within a predetermined range). Please). If they are the same color, the target color (the average color value of all the pixels of the black MCU) is determined as a peripheral color in S79. This is because the color change is flat in the surrounding MCU that does not include the character area, and therefore, by replacing all the pixels of the MCU (1) or MCU (2) with the color of the above average value, This is to eliminate dullness. If they are not the same color, the target pixel is set as a peripheral color in S80. This is because if the surrounding MCU has extremely different colors, the average value of the colors of the pixels in the surrounding MCU (black MCU) will be different from the colors of the surrounding MCU. This is to prevent the color from being replaced. If it is determined in S73 that all the pixels included in the MCU among the surrounding MCUs are not MCUs existing outside the character area, the process proceeds to S80 and the process is terminated as described above.

  The above is the determination method of the peripheral color. This flowchart uses the characteristic of the MCU that the mosquito noise is closed in the MCU, and the accuracy of determining the peripheral color can be improved.

  Next, a means for determining whether or not the target pixel on the mask data is in the vicinity of the character in S47 shown in FIG.

  FIG. 20 is a diagram illustrating an image obtained by decompressing JPEG, mask data, and one raster data of each data.

  20A shows an image obtained by decompressing JPEG, and FIG. 20B shows mask data. 20C and 20D are diagrams showing one raster data of each data.

  Mosquito noise can occur outside character boundaries. X and Y shown in FIG. 20B are pixels outside the boundary of the character. However, if they are in the same MCU, they may occur in a further outside pixel (gray pixel portion). For this reason, this determination means can be realized by determining whether or not the target pixel has a character boundary pixel in the same MCU.

  The above is the detailed description of the first embodiment.

  According to the first embodiment, since the data to be transmitted to the printer is the compressed image and the binary mask data, the amount of transmission data can be reduced and the printing speed can be improved as compared with the raster data. it can.

  Further, according to the first embodiment, the periphery of the character can be filled with the peripheral color using the mask data, so that the mosquito noise generated around the character in the compressed image can be reduced, Good printing results can be obtained.

Furthermore, according to the above embodiment, the mask data can be used to fill the character area with the fill color, so that it is possible to reduce the dullness of the character color generated at the boundary of the character portion, which is favorable. Printing results can be obtained.

  The second embodiment of the present invention is an embodiment in the case of inputting a document image from a card input device mounted on a printer.

  Since the printer hardware configuration according to the second embodiment is the same as that of the first embodiment, the description thereof is omitted. Further, the configuration in the printer according to the second embodiment is also the same as that of the first embodiment, so that FIG. 2 and FIG.

  An example of data to be printed by the printer system PS2 that is Embodiment 2 is the same as the example of data shown in FIG. This data includes image, character, and graphics data.

  Next, the configuration of the printer system PS2 will be described.

  FIG. 21 is a block diagram illustrating a printer system PS2 that is Embodiment 2 of the present invention.

  The printer system PS2 includes a printer control device 60, a printer device 200, and a storage area 80.

  The printer control device 60 includes a printer driver 61 and a data transmission unit 62.

  The printer driver 61 includes a print data acquisition unit 611, an all image data generation unit 612, a character image data generation unit 613, a compressed data generation unit 614, a mask data generation unit 615, and a data output unit 616.

  Next, the printer apparatus 200 will be described.

  The printer apparatus 200 includes a data receiving unit 71, a compressed data decoding unit 72, a mask data analysis unit 73, a fill color / peripheral color determination unit 74, a print data generation unit 75, and a data printing unit 76.

  The printer device 200 and the printer control device 60 are connected by a bidirectional interface. Further, an external storage area 80 such as a memory card is provided.

  The data shown in FIG. 4 is converted into data that the printer driver 61 in the printer control device 60 transmits to the printer. In the printer driver 61, first, the print data acquisition unit 611 acquires the print data. All the image data generation unit 612 renders the acquired data on the memory as multi-value RGB data.

  Further, the character image data generation unit 613 renders the character data of the print data on another memory as RGB data of only characters. FIG. 6 shows the input print data in this state and the rendering results on the two memories. 6A is an arbitrary input image, FIG. 6B is the entire image rendering result, and FIG. 6C is the rendering result of only the character portion. On the print data, there are objects such as characters, images, and graphics, but there is an overlap for each.

  For this reason, as shown in FIG. 6C, the rendering result of the character part is only the character existing in the highest layer. In FIG. 6C, a part of the character string is cut off by the image.

  Next, the compressed data generating unit 614 compresses all images rendered by the all image data generating unit 612, and the compressed data is stored in the external storage area 80. When compressing, an irreversible compression method such as JPEG is used.

  Thereby, the amount of data to be transferred can be reduced. On the other hand, the character part image (C) generated by the character image data generation unit 613 is transferred to the mask data generation unit 615, and mask data is generated and stored in the external storage area 80 by the processing described later. The above is the processing in the printer control device 60.

  Next, processing of the printer apparatus 200 will be described.

  In the printer control device 60, the external storage area 80 is mounted in a card slot in the printer. The compressed data and the mask data are read from the external storage area 80 according to a command from the user interface of the printer device 200. The data receiving unit 71 receives the read data.

  Among the received data, the compressed data decoding unit 72 decodes the compressed data. The decoded result is shown in FIG. Since the result of FIG. 7A is obtained by decompressing irreversibly compressed data, mosquito noise in JPEG compression and color dullness are generated around the character.

  Next, the mask data analysis unit 73 analyzes the received mask data. The mask data is data for only the character portion in FIG. Next, the fill color / peripheral color determination unit 74 selects colors to be applied to the character portion and the periphery of the data decoded by the compressed data decoding unit 72 and the data obtained by decoding the analysis result performed by the mask data analysis unit 73. decide. Details of this processing will be described later.

  The print data generation unit 75 overwrites the decoded data with the determined fill color and peripheral color, and the data printing unit 76 prints the data. FIG. 7C shows the printing result. The above is the processing of the printer apparatus 200.

  The above is the operation of the printer system PS2 in the second embodiment.

  In addition, since other processes related to the second embodiment are the same as the processes in the first embodiment, the description thereof is omitted.

  According to the second embodiment, since the data stored in the external storage area 80 is a compressed image and binary mask data, the amount of transmission data can be reduced compared to raster data, and the printing speed can be reduced. Can be improved.

  Further, according to the second embodiment, since the periphery of the character can be painted with the peripheral color using the mask data, mosquito noise generated around the character in the compressed image can be reduced, Good printing results can be obtained.

Furthermore, according to the second embodiment, the character area can be filled with the fill color using the mask data, so that the dullness of the character color generated at the boundary of the character portion can be reduced, which is favorable. Printing results can be obtained.

  A third embodiment of the present invention is a storage medium that records a program code of software that realizes the functions of the first embodiment.

  In this embodiment, the computer (or CPU or MPU) of the printer apparatus 100 reads and executes the program code stored in the storage medium.

  In this case, the program code itself read from the storage medium realizes the function of the first embodiment, and the storage medium storing the program code constitutes the present invention.

  The storage medium for supplying such program code is, for example, a floppy (registered trademark) disk, hard disk, optical disk, magneto-optical disk, CD-ROM, CD-R, magnetic tape, nonvolatile memory card, ROM. is there.

  Further, the functions of the above-described embodiments are realized by executing the program code read by the computer. In addition, the OS (operating system) running on the computer executes part or all of the actual processing based on the instruction of the program code, and the functions of the above embodiments are realized by this processing. This is also included.

  Furthermore, the present invention is realized even when the program code read from the storage medium is written in a memory provided in a function expansion board inserted into the computer or a function expansion unit connected to the computer. The CPU of the function expansion board or function expansion unit executes part or all of the actual processing based on the instruction of the program code, and the functions of the above embodiments may be realized by the processing. Including.

  That is, the reading unit 4 is an example of a first conversion unit that converts each object in the document data into an image image, and is an example of a second conversion unit that converts only a character object into an image image.

  The image processing unit 24 is an example of a compressed image generation unit that generates a compressed image by compressing the image image converted by the first conversion unit, and scales the image image converted by the second conversion unit. It is an example of an image scaling means. The image processing unit 24 is an example of an outline image extracting unit that extracts an outline image from the image that has been scaled by the image scaling unit, and a mask that generates a mask image based on the extracted outline image. It is an example of an image generation means. Furthermore, the image processing unit 24 is an example of an image decompressing unit that decompresses the compressed image, and a color that determines a character fill color and a character peripheral color based on the decompressed image and the mask image. It is an example of a determination means. The image processing unit 24 is an example of an image generation unit that generates an image based on the expanded image, the mask image, the fill color, and the peripheral color.

  The input device 32 is an example of an input device that inputs an image to the image processing device. The display device 31 is an example of a display device that displays an image generated by the image processing device.

In addition, the said Example can be grasped | ascertained as a method invention. That is, in the above-described embodiment, the first conversion process for converting each object in the document data into an image and the compressed image generation for generating the compressed image by compressing the image image converted in the first conversion process. It is an example which implement | achieves a process. Moreover, the said Example is an example which implement | achieves the 2nd conversion process which converts only a character object into an image image, and the image scaling process which scales the image image converted by the said 2nd conversion process. . Further, the embodiment includes an outline image extraction step for extracting an outline image from the image scaled in the image scaling step, and a mask image generation step for generating a mask image based on the extracted outline image; It is an example which implement | achieves. The embodiment includes an image expansion step of expanding the compressed image, and a color determination step of determining a character fill color and a character peripheral color based on the expanded image and the mask image. This is an example of realization. The above embodiment is an example of realizing an image generation process for generating an image based on the expanded image, the mask image, the fill color, and the peripheral color.

1 is a schematic perspective view of a printer apparatus 100 that is Embodiment 1 of the present invention. 1 is a diagram illustrating a configuration of a printer device 100. FIG. 1 is a block diagram showing a printer system PS1 including a printer device 100. FIG. FIG. 6 is a diagram illustrating an example of data to be printed by the printer system PS1. 1 is a diagram illustrating a configuration of a printer system PS1. It is a figure which shows input print data and the rendering result on two memories. It is a figure which shows the decoded result. 3 is a flowchart illustrating processing operations of the printer apparatus 100. It is a flowchart which shows the processing operation of all the image data generation parts 412-mask data generation part 415. It is a flowchart which shows the operation | movement of mask data creation in S18. It is a figure which shows the process of simple expansion. It is a figure which shows the original image of a character part, the result of having expanded this twice, the result of extracting an outline from this result, and the result of binarizing this. It is a figure which shows a binarization process. It is the figure which extracted the outline, and the figure which expanded the arrow part. 6 is a flowchart illustrating processing operations of a compressed data code unit 52 to a print data generation unit 55. Outline mask data of the upper part of the character A, and one square represents one MCU of a corresponding JPEG image. 6 is a flowchart illustrating processing for determining a fill color in the first embodiment. It is a figure which shows the outline mask data of the upper part of the character A. 6 is a flowchart illustrating processing for determining a peripheral color in the first embodiment. It is a figure which shows the image which expanded JPEG, mask data, and 1 raster data of each data. FIG. 6 is a block diagram illustrating a printer system PS2 that is Embodiment 2 of the present invention. In Example 2 of this invention, it is a figure which shows the mosquito noise on a decoding data, and the dullness of a color.

Explanation of symbols

100: Printer device,
1 ... display part,
2 ... operation part,
4 ... reading unit,
5 ... Recording part,
20 ... CPU,
31 ... display device,
32 ... Input device,
PS1 ... Printer system,
40. Printer control device,
41 ... printer driver,
411 ... print data acquisition unit,
412 ... all image data generation unit,
413 ... a character image data generation unit,
414 ... a compressed data generation unit,
415 ... Mask data generation unit,
416 ... Data output unit,
42 ... data transmission unit,
51: Data receiving unit,
52 ... Compressed data decoding unit,
53. Mask data analysis unit,
54: Fill color / peripheral color determination section,
55. Print data generation unit,
56: Data printing section,
PS2 ... Printer system,
60 ... Printer control device,
61 ... Printer driver,
200: Printer device.

Claims (3)

First conversion means for converting each object in the document data into an image;
Compressed image generation means for generating a compressed image by compressing the image image converted by the first conversion means;
A second conversion means for converting only a character object into an image;
Image scaling means for scaling the image image converted by the second conversion means;
Outline image extraction means for extracting an outline image from the image scaled by the image scaling means;
Mask image generation means for generating a mask image based on the extracted outline image;
Image decompression means for decompressing the compressed image;
Color determining means for determining a fill color of a character and a surrounding color of the character based on the expanded image and the mask image;
Image generating means for generating an image based on the expanded image, the mask image, the fill color, and the peripheral color;
An image processing apparatus comprising: A first conversion unit that converts each object in the document data into an image, a compressed image generation unit that generates a compressed image by compressing the image image converted by the first conversion unit, and a character object only. Extracting an outline image from the second conversion means for converting to an image, the image scaling means for scaling the image image converted by the second conversion means, and the image scaled by the image scaling means An outline image extracting means, a mask image generating means for generating a mask image based on the extracted outline image, an image expanding means for expanding the compressed image, the expanded image, and the mask image. A color determining means for determining a fill color of the character and a peripheral color of the character, the decompressed image, the mask image, and the fill color; Based on the above surrounding color, an image processing apparatus comprising an image generating means for generating an image;
An input device for inputting an image to the image processing device;
A display device for displaying an image generated by the image processing device;
A printer system comprising: A first conversion step of converting each object in the document data into an image;
A compressed image generation step of compressing the image image converted in the first conversion step to generate a compressed image;
A second conversion step of converting only a character object into an image;
An image scaling step for scaling the image image converted in the second conversion step;
An outline image extraction step of extracting an outline image from the image scaled in the image scaling step;
A mask image generation step of generating a mask image based on the extracted outline image;
An image decompression step of decompressing the compressed image;
A color determination step for determining a fill color of the character and a peripheral color of the character based on the expanded image and the mask image;
An image generation step of generating an image based on the expanded image, the mask image, the fill color, and the peripheral color;
A control method for an image processing apparatus, comprising:

Images