JP2023158554A - Character image quality adjustment system, character image quality adjustment device, and control method and program therefor - Google Patents

Abstract

To provide a character image quality adjustment system, a character image quality adjustment device, a method, and a program for adjusting character image quality by acquiring a parameter for adjusting image quality of characters according to its print data even if attribute information of the characters cannot be extracted from PDL analysis results of original print data.SOLUTION: Character image quality adjustment processing for adjusting character image quality by reading printed matter printed by a printing device determines whether or not character attributes are included by analyzing PDL data of the printed matter, extracts a corresponding character area if the character attributes are included, and analyzes image data obtained by rendering print data if the character attributes are not included. Then, character information of a reference image corresponding to the character area extracted from the image data obtained by analyzing or rendering the PDL data is compared with character information of image data for inspection, and the printing device is instructed to adjust a parameter of a printing process according to the result.SELECTED DRAWING: Figure 3

Description

The present invention relates to a character image quality adjustment system, a character image quality adjustment device, a control method thereof, and a program.

2. Description of the Related Art In a printing device, during the printing process (charging, exposure, development, etc.), characters may become thicker or thinner in the character portion of printed matter. In order to eliminate such thickening and thinning of characters, a technique is known that changes the thickness and density of characters based on attribute information included in the original print data. Patent Document 1 describes a technique for analyzing a print command written in a printer description language (PDL=Page Description Language) and changing the thickness and density of characters based on the obtained attribute information.

Furthermore, a technology has been proposed in which the state of characters on printed matter is determined based on scanned image data obtained by reading the outputted printed matter and original image data (reference image), and is automatically adjusted. In Patent Document 2, a printing process is performed based on image data input to a printing device, and the outputted printed matter is scanned by a reading device to obtain read image data. Then, a character area is extracted from the read image data, and the difference between the original image data and the read image data is calculated for each pixel of the character area. A technique is described in which the difference value is integrated to determine whether the character is thick or thin, and printing parameters are adjusted according to the condition.

Japanese Patent Application Publication No. 11-129547 Japanese Patent Application Publication No. 2015-52886

However, the technique described in Patent Document 1 cannot perform adjustment processing if character attribute information is not included in the PDL analysis result of the original print data. Furthermore, the technique described in Patent Document 2 does not utilize PDL analysis results, and therefore cannot utilize character types or character sizes. Furthermore, there is a possibility that characters may not be detected or that objects other than characters may be erroneously detected as characters, and in such cases, there is a possibility that printing parameters cannot be accurately determined.

An object of the present invention is to solve at least one of the problems of the prior art described above.

An object of the present invention is to adjust the character image quality by acquiring parameters for adjusting the character image quality according to the print data even when character attribute information cannot be extracted from the PDL analysis result of the original print data. The goal is to provide technology.

In order to achieve the above object, a character image quality adjustment system according to one aspect of the present invention has the following configuration. That is,
A character that includes an information processing device that outputs print data to a printing device and causes it to be printed, and a character image quality adjustment device that reads the printed material printed by the printing device and adjusts the character image quality of the printed material printed by the printing device. An image quality adjustment system,
The information processing device includes:
a first extraction means for analyzing PDL data of print data for printing the printed material to determine whether or not it includes a character attribute, and if the character attribute is included, extracting a character area corresponding to the character attribute;
When the first extraction means determines that the character attribute is not included, the image data obtained by rendering the print data is analyzed to determine whether or not the character attribute is included, and if the character attribute is included, the image data is a second extraction means for extracting a character area corresponding to a character attribute;
The character image quality adjustment device includes:
reading means for reading the printed matter to obtain inspection image data;
Comparing means for comparing the character information of the reference image and the character information of the inspection image data corresponding to the character area extracted by the first extraction means or the second extraction means;
and instruction means for instructing the printing apparatus to adjust parameters of the printing process according to the comparison result of the comparison means,
The printing device includes:
Adjustment means for adjusting character image quality included in print data received from the information processing device in accordance with instructions from the instruction means;
The present invention is characterized by comprising a printing unit that prints according to print data whose character image quality has been adjusted by the adjusting unit.

According to the present invention, even if character attribute information cannot be extracted from the PDL analysis result of the original print data, the character image quality can be adjusted by obtaining parameters for adjusting the character image quality according to the print data. There is an effect.

Other features and advantages of the invention will become apparent from the following description with reference to the accompanying drawings. In addition, in the accompanying drawings, the same or similar structures are given the same reference numerals.

The accompanying drawings are included in and constitute a part of the specification, illustrate embodiments of the invention, and together with the description serve to explain the principles of the invention.
1 is a diagram showing an example of an inspection and character image quality adjustment system including a printing system according to Embodiment 1 of the present invention. FIG. 2 is a block diagram illustrating the hardware configurations of a printing device, an external controller, a character image quality adjustment device, and a client PC of the inspection and character image quality adjustment system according to the first embodiment. 7 is a flowchart illustrating character adjustment processing in the inspection and character image quality adjustment system according to the first embodiment. An image of a printed matter printed with the kanji ``jo'' specified in KozMinPr6N-Regular font with a character size of 5pt (points). 5 is a diagram illustrating an example of a PDF description of a PDL file for acquiring the printed matter in FIG. 4. FIG. 5 is a flowchart illustrating coordinate analysis processing of a character portion by an external controller according to the first embodiment. Schematic diagrams (A) to (D) illustrating character extraction processing and transformation processing of characters, and diagram (E) illustrating an affine transformation formula. A schematic diagram for explaining the quantification of character characteristics. The figure which shows an example of the table which shows the relationship between character fatness degree (alpha) and adjustment level Lc. The figure which shows an example of character adjustment using an adjustment level. 7 is a flowchart illustrating character adjustment processing in the inspection and character image quality adjustment system according to Embodiment 2 of the present invention. FIG. 7 is a diagram illustrating an example of a screen for a user to specify a character position, which is displayed on a UI display unit of a character image quality adjustment device according to a second embodiment. 13 is a flowchart illustrating the character information acquisition and storage processing in S1102 of FIG. 12.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the claimed invention. Although a plurality of features are described in the embodiments, not all of these features are essential to the invention, and the plurality of features may be arbitrarily combined. Furthermore, in the accompanying drawings, the same or similar components are designated by the same reference numerals, and redundant description will be omitted.

[Embodiment 1]
FIG. 1 is a diagram showing an example of an inspection and character image quality adjustment system including a printing system 101 according to Embodiment 1 of the present invention.

The printing system 101 is connected to an external controller 102 (information processing device). The printing system 101 and external controller 102 constitute an image processing system. The printing system 101 is sometimes referred to as, for example, an image forming apparatus, a multifunction peripheral, or a multifunction peripheral (MFP). The printing system 101 and the external controller 102 are communicably connected via an internal LAN 105 and a video cable 106. The external controller 102 is communicably connected to the client PC 103 via an external LAN 104. External controller 102 may be referred to as an image processing controller, digital front end (DFE), or print server, for example.

The client PC 103 can issue a print instruction to the external controller 102 via the external LAN 104. A printer driver is installed on the client PC 103. This printer driver has a function of converting print data into printer description language (PDL) data that can be processed by the external controller 102. By operating the client PC 103, the user can issue printing instructions to the printing system 101 from various applications installed on the PC 103 via the printer driver. The printer driver transmits print data, that is, PDL data, to the external controller 102 based on a print instruction from the user. When the external controller 102 receives PDL data from the client PC 103, it analyzes and interprets the received PDL data. Then, based on the result of this interpretation, rasterization processing is performed to generate bitmap image data with a resolution matching the printing system 101, and the bitmap image data is input to the printing system 101 to issue a print instruction. The resolution is usually 600 dpi, and in the case of high definition, there are many printing systems with 1200 dpi. Hereinafter, the resolution will be explained using an example of 600 dpi.

The printing system 101 includes a plurality of devices each having different functions, and is configured to be able to execute various processes such as bookbinding processing. In the first embodiment, the printing system 101 includes a printing device 107 , an inserter 108 , a character image quality adjustment device 109 , a large-capacity stacker 110 , and a finisher 111 . An image is printed by the printing device 107, and the sheet (paper) discharged from the printing device 107 is transported inside each device in the order of the inserter 108, character image quality adjustment device 109, large-capacity stacker 110, and finisher 111. Ru. In the first embodiment, the printing system 101 is an example of an image forming apparatus, but the printing apparatus 107 included in the printing system 101 may also be called an image forming apparatus, a multifunction peripheral, or a multifunction peripheral (MFP). be.

The printing device 107 forms (prints) an image using toner (developer) on a sheet that is fed or conveyed from a paper feeding unit arranged at the bottom of the printing device 107 . The inserter 108 inserts sheets into a series of sheet groups conveyed from the printing device 107. The character image quality adjustment device 109 inspects characters to adjust the image quality of printed characters. The character image quality adjustment device 109 is a device that transports a sheet on which an image is printed by the printing device 107 through a transport path, and adjusts the character image on the transported sheet to an appropriate image quality. More specifically, character adjustment processing consists of inspection and adjustment. The inspection is performed by comparing the image data obtained by reading the image printed on the conveyed sheet with a reference image, which is a bitmap image obtained by rasterizing the PDL data that is the original print data, to determine the characters printed on the sheet. Inspect (determine scratches, cracks, etc.). If the results of this inspection show that the characters are blurred or blurred, image processing settings and process settings are adjusted to ensure that the image quality of the characters is appropriate. The large-capacity stacker 110 is a device that can stack a large number of sheets. The finisher 111 is a device that can perform finishing processes such as stapling, punching, and saddle stitching on the transported sheets. The sheet processed by the finisher 111 is discharged to a predetermined paper discharge tray.

FIG. 2 is a block diagram illustrating the hardware configurations of the printing device 107, external controller 102, character image quality adjustment device 109, and client PC 103 of the inspection and character image quality adjustment system according to the first embodiment.

First, the printing device 107 will be explained.

The printing device 107 includes a communication I/F (interface) 217, a network I/F 218, a video I/F 220, an HDD 221, a CPU 222, a memory 223, and a UI display section 225. The printing device 107 further includes an image processing section 224 and a printing section (printer engine) 226. These are connected to each other via a system bus 213, respectively.

Communication I/F 217 is connected to inserter 108 , character image quality adjustment device 109 , large-capacity stacker 110 , and finisher 111 via communication cable 260 . The CPU 222 communicates with each device via the communication I/F 217. Network I/F 218 is connected to external controller 102 via internal LAN 105 and is used for communication of control data and the like. Video I/F 220 is connected to external controller 102 via video cable 106 and is used for communicating data such as image data. Note that the printing device 107 (printing system 101) and the external controller 102 may be connected only by the video cable 106 as long as the operation of the printing system 101 can be controlled by the external controller 102.

Various programs or data are stored in the HDD 221. The CPU 222 controls the operation of the printing apparatus 107 by expanding the program stored in the HDD 221 into the memory 223 and executing it. The memory 223 stores programs and data necessary for the CPU 222 to perform various processes. Furthermore, the memory 223 operates as a work area for the CPU 222. The UI display unit 225 receives various setting inputs and operation instructions from the user, and is used to display various information such as setting information and print job processing status.

The image processing unit 224 converts the bitmap image data generated by the external controller 102 into image data optimal for the printing system 101. For example, if it is color data, color conversion processing is performed to optimally convert the color, and if it is text, character adjustment processing (thin line thickness adjustment processing) is performed to convert thin line portions to optimal thickness. More specifically, in a certain printing system, if a black thin line portion becomes faint, a fine line thickness adjustment process is performed in advance to thicken the black thin line, and an appropriate black thin line is printed. In addition, if the white thin line portion is crushed, thin line thickness adjustment processing is performed in advance to thin the white thin line, and an appropriate white thin line is printed.

The print unit 226 applies toner to the sheet fed and conveyed from the paper feed unit located at the bottom of the printing device 107 based on the print data converted into a bitmap optimal for printing by the image processing unit 224. (Developer) to form (print) an image.

The inserter 108 controls the feeding of the inserted sheet from the paper feeding unit and the conveyance of the sheet conveyed from the printing device 107.

The character image quality adjustment device 109 includes a communication I/F 237, a CPU 238, a memory 239, an image reading section 240, a UI display section 242, and an HDD 255. These devices are connected to each other via system bus 243. Communication I/F 237 is connected to printing device 107 via communication cable 260. The CPU 238 performs communication necessary for controlling the character image quality adjustment device 109 via the communication I/F 237. CPU 238 controls the operation of character image quality adjustment device 109 by executing a control program stored in memory 239. A control program for the character image quality adjustment device 109 is stored in the memory 239.

The image reading unit 240 reads the conveyed sheet according to instructions from the CPU 238. The CPU 238 stores the image data read by the image reading unit 240 in the memory 239 as inspection image data (hereinafter referred to as inspection image data). The CPU 238 further uses a bitmap image obtained by rasterizing the PDL data as a reference image and compares it with inspection image data to inspect the reproducibility of the characters printed on the sheet and performs character adjustment processing to determine the amount of character adjustment. .

The UI display section 242 is used to display character adjustment results, setting screens, and the like. The UI display unit 242 is operated by the user and receives various instructions from the user (for example, changing the settings of the character image quality adjustment device 109, specifying the type and size of characters to be inspected, etc.). The HDD 255 stores various setting information and image data necessary for character adjustment. Various setting information and image data stored in the HDD 255 can be reused.

Next, the stacker 110 will be explained.

The stacker 110 controls whether the sheet conveyed through the conveyance path is discharged to a stack tray, an escape tray, or to a finisher 111 connected to the downstream side in the sheet conveyance direction. conduct.

Next, the finisher 111 will be explained.

The finisher 111 controls the conveyance and discharge of sheets, and performs finishing processing such as stapling, punching, or saddle stitching.

Next, the external controller 102 will be explained.

The external controller 102 includes a CPU 208, a memory 209, an HDD 210, a keyboard 211, a display section 212, network I/Fs 213 and 214, and a video I/F 215. These devices are connected to each other via system bus 216. The CPU 208 controls the operation of the external controller 102 by expanding the program stored in the HDD 210 into the memory 209 and executing it. For example, it executes receiving PDL data from the client PC 103, RIP processing for rasterizing the PDL data, processing for transmitting print data to the printing system 101, and the like. The memory 209 stores programs and data necessary for the CPU 208 to perform various processes. Furthermore, the memory 209 operates as a work area for the CPU 208.

Various programs and data are stored in the HDD 210. The keyboard 211 is used to input operating instructions for the external controller 102 from the user. The display unit 212 is used, for example, to display information about the application being executed on the external controller 102 and an operation screen. The network I/F 213 is connected to the client PC 103 via the external LAN 104 and is used for communicating data such as print instructions. The network I/F 214 is connected to the printing device 107 via the internal LAN 105 and is used for communicating data such as print instructions. The video I/F 215 is connected to the printing device 107 via the video cable 106 and is used for communicating data such as image data (print data).

Next, the client PC 103 will be explained.

The client PC 103 includes a CPU 201, a memory 202, an HDD 203, a keyboard 204, a display section 205, and a network I/F 206. These devices are connected to each other via system bus 207. The CPU 201 controls the operation of each device via the system bus 207 by loading programs stored in the HDD 203 into the memory 202 and executing them. This allows the client PC 103 to perform various types of processing. For example, the CPU 201 generates print data and issues a print instruction by loading a document processing program stored in the HDD 203 into the memory 202 and executing it. The memory 202 stores programs and data necessary for the CPU 201 to perform various processes. Furthermore, the memory 202 operates as a work area for the CPU 201.

The HDD 203 stores various applications (for example, document processing programs), programs such as printer drivers, and various data. The keyboard 204 is used to input operating instructions for the client PC 103 from the user. The display unit 205 is used, for example, to display information about the application being executed on the client PC 103 and an operation screen. Network I/F 206 is communicably connected to external controller 102 via external LAN 104. The CPU 201 communicates with the external controller 102 via the network I/F 206.

In the inspection and character image quality adjustment system shown in FIG. 1, the external controller 102 is connected to the printing system 101, but the present invention is also applicable to a configuration different from this. For example, a configuration may be adopted in which the printing system 101 is connected to an external LAN 104 and print data is transmitted from the client PC 103 to the printing system 101 without going through the external controller 102. In this case, data analysis, interpretation, and rasterization of print data are executed by the printing system 101. In this case, the character image quality adjustment device 109 may receive the PDL interpretation result and rasterized image data from the printing system, and extract the character area included in the print data. Alternatively, the character image quality adjustment device 109 may perform PDL interpretation and rasterization to extract character areas included in the received print data.

FIG. 3 is a flowchart illustrating character adjustment processing in the inspection and character image quality adjustment system according to the first embodiment.

In step S301, the external controller 102 receives a print job from the client PC 103 and starts processing according to the print job. In Embodiment 1, for the sake of simplicity, the print job includes a PDL file, and the PDF file includes PDF (Portable Document Format) data including character images, etc., or may not include character images, etc. shall be taken as a thing. The following explanation will be given using an example in which the client PC 103 transmits this PDF file to the external controller 102 and issues a print instruction.

In step S302, the CPU 208 of the external controller 102 obtains the font type, size, designated paper position, etc. of characters included in the print job based on the description in the PDF file.

FIG. 4 is an image diagram of a printed matter 401 on which the kanji character "jo" 402 specified in KozMinPr6N-Regular font with a character size of 5 pt (points) is printed.

FIG. 5 is a diagram illustrating an example of a description of a PDF (Portable Document Format) of a PDL file from which the printed matter 401 of FIG. 4 is obtained.

FIG. 6 is a flowchart illustrating coordinate analysis processing of a character portion by the external controller 102 according to the first embodiment. The character part coordinate analysis process executed in the PDL interpretation process of S302 will be described below with reference to FIGS. 4, 5, and 6. Note that the process shown in the flowchart of FIG. 6 is realized by the CPU 208 of the external controller 102 executing a program developed in the memory 209.

In step S601, the CPU 208 acquires the font type, font size, and font settings used for character inspection that are set in advance on a character inspection setting screen (not shown). Here, as an example, the font is the Kanji character "jo" (character code "8fee"), the font size is 7 pt or less, and the font type is KozMinPr6N-Regular. This is just an example, and is not limited to any font whose character adjustment can be inspected. In character inspection, it is desirable that the characters include portions with thin lines and include portions that can be compared with a reference image to determine whether the lines are thick or thin.

Next, the process advances to S602, and the CPU 208 determines whether the specified font type "KozMinPr6N-Regular" is used in the description of /Type/Font in the font type designation section 501 of the PDL data in FIG. 5. If the specified font type is being used, the process advances to S603, but if it is not being used, the process ends. In the example of FIG. 5, KozMinPr6N-Regular is used, so the process advances to S603.

In S603, the CPU 208 determines whether the specified font code "8fee" is used in the description of /F0 in the font specification section 503 of the PDL data in FIG. 5. If the specified font code is being used, the process advances to S604; if it is not being used, the process ends. In the example of FIG. 5, the font code "8fee" is used, so the process advances to S604.

In S604, the CPU 208 determines whether a specified size of 7 pt or less is used in the description of /F0 in the font specification section 503 of the PDL data in FIG. 5. If the specified size is in use, the process advances to S605; if it is not in use, the process ends. In the example of FIG. 5, "5" is used, which is less than or equal to 7, so the process advances to S605.

In S605, the CPU 208 determines the upper left coordinates (x1, y1) of the character rectangle 402 from the description of "1.0.0.1.50.770.Cm" in the font specification section 503 of the PDL data in FIG. For this cm number, "1.0.0.1." indicates a square matrix and no rotation, and "50.770." indicates a parallel shift of 50 points to the right and 720 points upward. ing. That is, in the case of 600 dpi, the length 403 in FIG. 4 is 50 points, which corresponds to 416 pixels, and the length 404 is 720 points, which corresponds to 6000 pixels. Therefore, the upper left coordinates (x1, y1) = (416, 6000). Since the character size is 5 points, the size corresponds to 41 pixels. In this way, the lower right coordinates (x2, y2) can be obtained as (457, 6041).

Next, returning to FIG. 3, in S303, the CPU 208 rasterizes into bitmap image data according to the resolution setting based on the result of interpreting the PDL. Then, the process advances to step S304, and the CPU 208 uses the bitmap image data obtained by rasterization as a reference image. Then, the reference image is temporarily stored in the HDD 210 of the external controller 102, and then sent to the character image quality adjustment device 109, stored in the HDD 255 of the character image quality adjustment device 109, and used for later inspection of character portions. let The following description will be made assuming that the resolution of this reference image is 600 dpi.

Next, the process advances to S305, and the CPU 208 transmits the bitmap image data rasterized in S303 from the video I/F 215 to the video I/F 220 of the printing apparatus 107 through the video cable 106. Upon receiving this bitmap image data, the CPU 222 of the printing device 107 processes the bitmap image data in the image processing unit 224, and prints in the print unit 226 according to the processed image data.

Next, the process advances to step S306, and the CPU 208 determines whether or not the original print data includes character attribute information. Here, the external controller 102 determines whether the PDL data includes a character object based on the result of the PDL data analysis performed in S302. If a character object is included, character attribute information is included, so the process moves to S307, and based on the analysis result of the PDL data, the character information of the character area is acquired, and the process moves to S311. In S307, character object information obtained by analyzing the PDL data is acquired. This character object information includes the font type, size, coordinate information, etc. of characters.

On the other hand, if it is determined in S306 that the character attribute is not included, the process advances to S308, where the CPU 208 extracts a character area from the bitmap image data rasterized in S303, and the process advances to S309. To extract this character region, there are, for example, a method of comparing the positions of objects obtained by contour detection, a method of detecting connected regions with close pixel values using an MSER (Maximally Stable Extremal Regions) feature detector, and a method of detecting connected regions with close pixel values. There is a method of extracting a character area using Recognition. Then, the process advances to S309, and the CPU 208 determines whether a character area has been detected in S308. If it is determined here that a character area exists, the process moves to S310, but if it is determined that a character area does not exist, it is determined that there are no characters in the original print data, and this character adjustment process ends. . In S310, the CPU 208 acquires character information of the character area extracted in S308. Specifically, character information included in the extracted character area is acquired. Note that in the case of extraction by OCR, in addition to the character area, character information such as font information may also be acquired.

The process then proceeds to S311, and the CPU 238 of the character image quality adjustment device 109 reads the image of the printed material to be inspected using the image reading unit 240 to obtain inspection image data. The image reading unit 240 reads the printed matter at a resolution of 600 dpi and saves it as image data at a resolution of 600 dpi.

Next, the process advances to S312, and the CPU 238 extracts character information of the character area from the inspection image data. Here, the external controller 102 receives the character area and character information acquired in S307 or S310 from the external controller 102, and based on it, extracts the character information included in the character area from the reference image and inspection image data. Next, the process advances to S313, and the CPU 238 transforms (positions) the character information on the characters of the inspection image data extracted in S312.

FIG. 7 is a schematic diagram (A) to (D) illustrating character extraction processing and character information transformation processing, and a diagram (E) illustrating an affine transformation formula.

FIG. 7(A) shows the character part of the original print data, and a broken line rectangle 701 shows the character area obtained in S306 or S309, and the upper left coordinates (x1, y1) and lower right coordinates (x2 , y2) gives the coordinates of the character area. FIG. 7(B) shows the character area of the inspection image data. Here, in the inspection image data, characters may not fit within the rectangle 702 determined from the character position information of the original print data due to positional deviation or expansion/contraction during reading. Therefore, when cutting out characters from the inspection image data, it is desirable to cut out a slightly larger range (broken line rectangle 703).

FIG. 7C is a schematic diagram illustrating the deformation process. In the first embodiment, a deformation process using affine transformation will be described, but the alignment method is not limited to this. Image conversion parameters are determined from a printing source character image 704 obtained by cutting out original print data using a dashed rectangle 701 and an inspection character image 705 obtained by cutting out inspection image data using a broken line rectangle 702. Corresponding feature points 706 are detected from the print source character image 704 and the inspection character image 705. The feature points connected by dash-dotted lines are corresponding feature points. A known method such as AKAZE can be used to detect these feature points. Deformation correction parameters are calculated so that the coordinates of the obtained feature points match. In the process of deforming and correcting the coordinate position of (x', y') to (x, y), a to f of the affine transformation shown in FIG. 7(E) serve as correction parameters.

The characters in the inspection image data are transformed (aligned) using the parameters thus calculated. FIG. 7(D) shows a reference character image 707 to be printed and a test character image 708 after alignment.

Next, in S314, the CPU 238 quantifies character characteristics. Here, first, the character 707 of the reference image aligned in S313 and the character 708 of the inspection image are compared, and difference data is acquired based on the comparison result. Specifically, a difference value between pixel values is calculated for each pixel at the same position in the reference character image 707 and the test character image 708. This difference value is calculated using the following formula.

Difference value = (pixel value of text in test image) - (pixel value of text in reference image)
FIG. 8 is a schematic diagram for explaining the quantification of character characteristics.

FIG. 8(A) is an enlarged view of a portion of the character 709 in the reference image of FIG. 7(D), and FIG. 8(B) is an enlarged view of a portion of the character 910 of the inspection image of FIG. 7(D). be. Pure black pixels represent the text portion. Here, to simplify the explanation, a binarized image (pure white 255, pure black 0) is used, but a color image with 8 bits for each color of RGB may be used as is.

FIG. 8(C) is difference data obtained from FIG. 8(A) and FIG. 8(B). A pure black pixel has a difference value (0), a pure white pixel has a difference value (255), and a diagonally shaded pixel has a difference value (-255).

Next, based on this difference data, the amount of text thickening on the printed matter is calculated. First, the number N1 of pixels whose negative difference value is less than or equal to a predetermined negative threshold (th1) in the difference data is calculated. Subsequently, the number N2 of pixels whose positive difference value is greater than or equal to a predetermined positive threshold (th2) is calculated. Then, the character thickness α is calculated from the ratio of the difference in the number of pixels between N1 and N2 (N1-N2) to the number of pixels in the character portion of the inspection image.

α=(N1-N2)/(number of pixels in the text part of the inspection image)
For the difference data, in the case of FIG. 8C, if th1 and th2 are both set to 0 for simplicity, N1 becomes 1 and N2 becomes 8. Therefore, the value of the character fatness α in FIG. 8(B) is determined as α=(1-8)/30=−0.23 using the above-mentioned formula. Although a part of a character is used here for explanation, in reality, similar calculations are performed for the entire character. Through the above processing, the character characteristics can be quantified by the character thickness α.

If α takes a positive value, it is determined that the characters are thick, and the adjustment amount is changed to make the characters thinner. On the other hand, if α takes a negative value, it is determined that the characters are thin, and the adjustment amount is changed to make the characters thicker. The specific character adjustment process will be described in detail.

Next, the process advances to S315, and the CPU 238 determines whether character adjustment is necessary. Here, it is determined whether the character thickness α is within a tolerance value, and if it is within the tolerance value, the process is terminated without performing character adjustment. On the other hand, if the character thickness α is not within the allowable value, the process advances to S316 and character adjustment control is performed. Here, character adjustment control is performed based on the character thickness α determined in S314. First, the adjustment level Lc is determined based on the character thickness α. This adjustment level Lc is determined by, for example, preparing a table in which the character thickness α and the adjustment amount are associated with each other, and referring to the table.

FIG. 9 is a diagram showing an example of a table showing the relationship between character thickness α and adjustment level Lc.

For example, in the case of FIG. 8C, the obtained character thickness α is α=0.23, so referring to the table of FIG. 9, the adjustment level Lc can be determined to be +1. After determining the adjustment level Lc in this manner, the character image quality adjustment device 109 feeds back the determined adjustment level Lc to the printing device 107. Thereby, the printing apparatus 107 can perform character adjustment control by having the image processing unit 224 perform character adjustment processing using the adjustment level Lc from rendering.

Here, an example of character adjustment in the image processing unit 224 using the adjustment level Lc will be described using FIG. 10.

10(A), (B), (D), and (E) show images in which the image in FIG. 10(C) is adjusted in accordance with the value of the adjustment level Lc. Here, in the order of FIGS. 10(A), (B), (D), and (E), a line thinned by 1 (=0.5×2) pixel at adjustment level -2, 0. Line made thinner by 5 (=0.5×1) pixels, line made thicker by 0.5 (=0.5×1) pixels at adjustment level +1, 1 (=0.5×2) at adjustment level +2 It shows an image of lines with thicker pixels.

As shown in FIGS. 10(A) and 10(E), the adjustment to make the width thinner or thicker by 1 pixel is performed on one side of the image portion showing the line for the line image in FIG. 10(C), which is the input image. This is done by thinning out or adding one pixel to all pixels. Next, as shown in FIGS. 10(B) and 10(D), the adjustment to make the width thinner or thicker by 0.5 pixel shows the line for the line image in FIG. 10(C), which is the input image. This is done by thinning out or adding pixels on one side of the image part every other pixel.

In addition, in the determination in S306 of FIG. 3, if the amount of characters including character attribute information obtained by interpreting the PDL data is not a sufficient number to determine the characteristics such as the thickness of the subsequent characters, rendering is performed. Text information may also be extracted from the RIP image data obtained in .

As explained above, according to the first embodiment, when character information can be obtained from the analysis result of PDL data, the analysis result of PDL data is used, and when character information cannot be obtained from the analysis result of PDL data, rendering Character information is obtained by analyzing the image data. Thereby, even if the original print data does not include character attribute information, highly accurate character quantification and adjustment processing can be performed.

[Embodiment 2]
In the above-described first embodiment, an example has been described in which, when character information is not included in the analysis result of PDL data, character information is acquired by analyzing image data obtained by RIP and character adjustment is performed.

However, for special fonts such as logo characters, character information may not be obtained by analyzing PDL data or RIP image data. Embodiment 2 will be described with an example in which character adjustment is performed using character information specified by the user in addition to character information included in print data. In the second embodiment, the same devices and configurations as those in the first embodiment described above are given the same numbers, and their explanations will be omitted.

FIG. 11 is a flowchart illustrating character adjustment processing in the inspection and character image quality adjustment system according to Embodiment 2 of the present invention. In FIG. 11, the same processes as those shown in the flowchart of FIG. 3 described above are given the same reference numerals, and their explanations will be omitted.

In step S1101, the CPU 238 of the character image quality adjustment device 109 receives a character position specified by the user before executing the job.

FIG. 12 is a diagram showing an example of a screen displayed on the UI display unit 242 of the character image quality adjustment device 109 according to the second embodiment, for the user to specify a character position.

On this UI screen, the user can refer to the displayed preview image 1201 of the original print data and specify a character area 1202 within the image. A plurality of character areas 1202 may be specified. After the user specifies the character area 1202, by pressing the enter button 1203, the character area specified by the user is set.

Then, a job is started in S301, and when printing is completed in S305, character information is acquired and saved in S1102. The CPU 238 acquires character information in the character area of the original print data, and temporarily stores it in the memory 239 of the character image quality adjustment device 109.

FIG. 13 is a flowchart illustrating the character information acquisition and storage processing in S1102 of FIG. 12. In FIG. 13, the same processes as S306, S308, and S309 in FIG. 3 described above are given the same reference numerals, and their explanations will be omitted.

First, in S1302, it is determined whether there is a character area set by the user. If the user has set a character area in S1101 of FIG. 11, the CPU 238 acquires character information of the set character area and stores it in the memory 239 in S1302.

In S306, it is determined whether the original print data has character attribute information, and if character attribute information is included, the process moves to S1303, where character information is acquired based on the analysis result of the PDL data and stored in the memory 239. do. On the other hand, in S306, if the original print data does not have character attribute information, the CPU 238 proceeds to S308 and extracts a character area from the rendered image data. The process then proceeds to S309, and the CPU 238 determines whether a character area has been detected in S308. If a character area exists, the process advances to S1304, where the CPU 238 acquires character information from the character area, stores it in the memory 239, and advances to S1103. On the other hand, if the character area does not exist, S1304 is skipped and the process advances to S1103.

Returning to FIG. 11, in S1103, the CPU 238 refers to the memory 239 and determines whether the inspection image data includes character information. If it is determined that there is no character information, this process is terminated. On the other hand, if it is determined that there is character information, the process moves to S1104, where the CPU 238 reads out the character information stored in the memory 239 in S1102 and performs character adjustment control from S311 onwards.

In this second embodiment, if there is a character area set by the user, the quantification result of character information in the character area set by the user is used as the quantification result of character information in the character area obtained from PDL interpretation or a rendered image. Weighting may be performed so as to give more importance than the results of the analysis.

As described above, according to the second embodiment, by referring to the character area specified by the user, even if the character area is not extracted by analysis of PDL data or rendered image data, the character desired by the user can be extracted. It is also possible to quantify and adjust the

(Other embodiments)
The present invention provides a system or device with a program that implements one or more functions of the embodiments described above via a network or a storage medium, and one or more processors in a computer of the system or device reads and executes the program. This can also be achieved by processing. It can also be realized by a circuit (for example, ASIC) that realizes one or more functions.
(Item 1)
A character that includes an information processing device that outputs print data to a printing device and causes it to be printed, and a character image quality adjustment device that reads the printed material printed by the printing device and adjusts the character image quality of the printed material printed by the printing device. An image quality adjustment system,
The information processing device includes:
a first extraction means for analyzing PDL data of print data for printing the printed material to determine whether or not it includes a character attribute, and if the character attribute is included, extracting a character area corresponding to the character attribute;
When the first extraction means determines that the character attribute is not included, the image data obtained by rendering the print data is analyzed to determine whether or not the character attribute is included, and if the character attribute is included, the image data is a second extraction means for extracting a character area corresponding to a character attribute;
The character image quality adjustment device includes:
reading means for reading the printed matter to obtain inspection image data;
Comparing means for comparing the character information of the reference image and the character information of the inspection image data corresponding to the character area extracted by the first extraction means or the second extraction means;
and instruction means for instructing the printing apparatus to adjust parameters of the printing process according to the comparison result of the comparison means,
The printing device includes:
Adjustment means for adjusting character image quality included in print data received from the information processing device in accordance with instructions from the instruction means;
printing means for printing according to print data whose character image quality has been adjusted by the adjusting means;
A character image quality adjustment system characterized by having.
(Item 2)
The character image quality adjustment system according to item 1, wherein the reference image is generated from image data obtained by rendering the print data.
(Item 3)
The second extracting means analyzes the image data obtained by rendering the print data to extract the character attributes even when the first extracting means cannot extract enough character attributes to adjust the character image quality. 2. The character image quality adjustment system according to item 1 or 2, wherein the character image quality adjustment system extracts a character area corresponding to .
(Item 4)
The second extraction means includes a method of comparing the positions of objects obtained by contour detection, a method of detecting connected regions with close pixel values using an MSER (Maximally Stable Extremal Regions) feature detector, and a method of using OCR (Optical Character Recognition). 4. The character image quality adjustment system according to any one of items 1 to 3, wherein the character area is extracted using any of the methods for extracting a character area.
(Item 5)
Item 1, wherein the comparison means obtains a pixel value difference value for each pixel at the same position of the text information based on the text information of the reference image and the text information of the test image data. The character image quality adjustment system according to any one of items 4 to 4.
(Item 6)
Character image quality according to item 5, wherein the instruction means determines the thickness of the character based on the difference value, determines an adjustment level corresponding to the thickness, and instructs the printing device. adjustment system.
(Item 7)
7. The character image quality adjustment system according to item 6, wherein the adjustment means changes the print data so as to make the character line thicker or thinner depending on the adjustment level.
(Item 8)
The character image quality adjustment device includes:
further comprising specifying means for specifying a character area included in print data for printing the printed matter according to a user's specification;
Items 1 to 7, wherein the comparing means further compares the character information of the reference image and the character information of the inspection image data corresponding to the character area specified by the specifying means. Character image quality adjustment system described in any one item.
(Item 9)
The instruction means extracts a comparison result between the character information of the reference image and the character information of the inspection image data corresponding to the character area designated by the designation means to the first extraction means or the second extraction means. The method is characterized in that the parameter is instructed to be adjusted with more emphasis placed on a comparison result between the character information of the reference image and the character information of the inspection image data corresponding to the character area extracted by the means. Character image quality adjustment system described in item 8.
(Item 10)
A character image quality adjustment device that reads a printed matter printed by a printing device and adjusts the character image quality of the printed matter printed by the printing device,
reading means for reading the printed matter to obtain inspection image data;
a first extraction means for analyzing PDL data of print data for printing the printed material to determine whether or not it includes a character attribute, and if the character attribute is included, extracting a character area corresponding to the character attribute;
When the first extraction means determines that the character attribute is not included, the image data obtained by rendering the print data is analyzed to determine whether or not the character attribute is included, and if the character attribute is included, the image data is a second extraction means for extracting a character area corresponding to a character attribute;
Comparing means for comparing the character information of the reference image and the character information of the inspection image data corresponding to the character area extracted by the first extraction means or the second extraction means;
Instructing means for instructing the printing apparatus to adjust parameters of the printing process according to the comparison result of the comparison means;
A character image quality adjustment device comprising:
(Item 11)
11. The character image quality adjustment device according to item 10, wherein the reference image is generated from image data obtained by rendering the print data.
(Item 12)
The second extracting means analyzes the image data obtained by rendering the print data to extract the character attributes even when the first extracting means cannot extract enough character attributes to adjust the character image quality. The character image quality adjustment device according to item 10 or 11, characterized in that the character image quality adjustment device extracts a character area corresponding to .
(Item 13)
The second extraction means includes a method of comparing the positions of objects obtained by contour detection, a method of detecting connected regions with close pixel values using an MSER (Maximally Stable Extremal Regions) feature detector, and a method of using OCR (Optical Character Recognition). 13. The character image quality adjustment device according to any one of items 10 to 12, wherein the character area is extracted using any of the methods for extracting a character area.
(Item 14)
Item 10, wherein the comparing means obtains a pixel value difference value for each pixel at the same position of the character information based on the character information of the reference image and the character information of the test image data. The character image quality adjustment device according to any one of .
(Item 15)
Character image quality according to item 14, wherein the instruction means determines the degree of thickness of the character based on the difference value, determines an adjustment level corresponding to the degree of thickness, and instructs the printing device. Adjustment device.
(Item 16)
further comprising specifying means for specifying a character area included in print data for printing the printed matter according to a user's specification;
Items 10 to 15, wherein the comparing means further compares the character information of the reference image and the character information of the inspection image data corresponding to the character area specified by the specifying means. The character image quality adjustment device described in any one item.
(Item 17)
The instruction means extracts a comparison result between the character information of the reference image and the character information of the inspection image data corresponding to the character area designated by the designation means to the first extraction means or the second extraction means. The method is characterized in that the parameter is instructed to be adjusted with more emphasis placed on a comparison result between the character information of the reference image and the character information of the inspection image data corresponding to the character area extracted by the means. The character image quality adjustment device according to item 16.
(Item 18)
A control method for controlling a character image quality adjustment device that reads a printed matter printed by a printing device and adjusts the character image quality of the printed matter printed by the printing device, the method comprising:
a reading step of reading the printed matter to obtain inspection image data;
A first extraction step of analyzing PDL data of print data for printing the printed material to determine whether or not it includes a character attribute, and if the character attribute is included, extracting a character area corresponding to the character attribute;
If the first extraction step determines that the character attribute is not included, the image data obtained by rendering the print data is analyzed to determine whether the character attribute is included, and if the character attribute is included, the image data obtained by rendering the print data is analyzed. a second extraction step of extracting a character region corresponding to the character attribute;
a comparison step of comparing the character information of the reference image and the character information of the test image data corresponding to the character area extracted in the first extraction step or the second extraction step;
an instructing step of instructing the printing device to adjust parameters of a printing process according to the comparison result of the comparison step;
A control method characterized by having the following.
(Item 19)
A program for causing a computer to execute each step of the control method described in item 18.

The present invention is not limited to the above-described embodiments, and various changes and modifications can be made without departing from the spirit and scope of the present invention. Therefore, to set out the scope of the invention, the following claims are hereby appended.

102...External controller, 103...PC, 107...Printing device, 109...Text image quality adjustment device, 224...Image processing section, 240...Image reading section, 241...UI display section (Text image quality adjustment device)

Claims (19)

A character that includes an information processing device that outputs print data to a printing device and causes it to be printed, and a character image quality adjustment device that reads the printed material printed by the printing device and adjusts the character image quality of the printed material printed by the printing device. An image quality adjustment system,
The information processing device includes:
a first extraction means for analyzing PDL data of print data for printing the printed material to determine whether or not it includes a character attribute, and if the character attribute is included, extracting a character area corresponding to the character attribute;
When the first extraction means determines that the character attribute is not included, the image data obtained by rendering the print data is analyzed to determine whether or not the character attribute is included, and if the character attribute is included, the image data is a second extraction means for extracting a character area corresponding to a character attribute;
The character image quality adjustment device includes:
reading means for reading the printed matter to obtain inspection image data;
Comparing means for comparing the character information of the reference image and the character information of the inspection image data corresponding to the character area extracted by the first extraction means or the second extraction means;
and instruction means for instructing the printing apparatus to adjust parameters of the printing process according to the comparison result of the comparison means,
The printing device includes:
Adjustment means for adjusting character image quality included in print data received from the information processing device in accordance with instructions from the instruction means;
printing means for printing according to print data whose character image quality has been adjusted by the adjusting means;
A character image quality adjustment system characterized by having. 2. The character image quality adjustment system according to claim 1, wherein the reference image is generated from image data obtained by rendering the print data. The second extracting means analyzes the image data obtained by rendering the print data to extract the character attributes even when the first extracting means cannot extract enough character attributes to adjust the character image quality. 2. The character image quality adjustment system according to claim 1, wherein a character area corresponding to the character area is extracted. The second extraction means includes a method of comparing the positions of objects obtained by contour detection, a method of detecting connected regions with close pixel values using an MSER (Maximally Stable Extremal Regions) feature detector, and a method of using OCR (Optical Character Recognition). 2. The character image quality adjustment system according to claim 1, wherein the character area is extracted using any one of the methods for extracting a character area. 2. The comparing means, based on the character information of the reference image and the character information of the inspection image data, obtains a difference value between pixel values for each pixel at the same position of the character information. 1. The character image quality adjustment system described in 1. 6. The character according to claim 5, wherein the instruction means determines the thickness of the character based on the difference value, determines an adjustment level corresponding to the thickness, and instructs the printing apparatus. Image quality adjustment system. 7. The character image quality adjustment system according to claim 6, wherein said adjusting means changes said print data so as to make character lines thicker or thinner depending on said adjustment level. The character image quality adjustment device includes:
further comprising specifying means for specifying a character area included in print data for printing the printed matter according to a user's specification;
Claims 1 to 7, wherein the comparing means further compares character information of the reference image and character information of the inspection image data corresponding to the character area specified by the specifying means. The character image quality adjustment system according to any one of the above. The instruction means extracts a comparison result between the character information of the reference image and the character information of the inspection image data corresponding to the character area designated by the designation means to the first extraction means or the second extraction means. The method is characterized in that the parameter is instructed to be adjusted with more emphasis placed on a comparison result between the character information of the reference image and the character information of the inspection image data corresponding to the character area extracted by the means. The character image quality adjustment system according to claim 8. A character image quality adjustment device that reads a printed matter printed by a printing device and adjusts the character image quality of the printed matter printed by the printing device,
reading means for reading the printed matter to obtain inspection image data;
a first extraction means for analyzing PDL data of print data for printing the printed material to determine whether or not it includes a character attribute, and if the character attribute is included, extracting a character area corresponding to the character attribute;
When the first extraction means determines that the character attribute is not included, the image data obtained by rendering the print data is analyzed to determine whether or not the character attribute is included, and if the character attribute is included, the image data is a second extraction means for extracting a character area corresponding to a character attribute;
Comparing means for comparing the character information of the reference image and the character information of the inspection image data corresponding to the character area extracted by the first extraction means or the second extraction means;
Instructing means for instructing the printing apparatus to adjust parameters of the printing process according to the comparison result of the comparison means;
A character image quality adjustment device comprising: 11. The character image quality adjustment device according to claim 10, wherein the reference image is generated from image data obtained by rendering the print data. The second extracting means analyzes the image data obtained by rendering the print data to extract the character attributes even when the first extracting means cannot extract enough character attributes to adjust the character image quality. 11. The character image quality adjustment device according to claim 10, wherein a character area corresponding to the character area is extracted. The second extraction means includes a method of comparing the positions of objects obtained by contour detection, a method of detecting connected regions with close pixel values using an MSER (Maximally Stable Extremal Regions) feature detector, and a method of using OCR (Optical Character Recognition). 11. The character image quality adjusting device according to claim 10, wherein the character area is extracted using any one of the methods for extracting a character area. 2. The comparing means, based on the character information of the reference image and the character information of the inspection image data, obtains a difference value between pixel values for each pixel at the same position of the character information. 10. The character image quality adjustment device according to 10. 15. The character according to claim 14, wherein the instruction means determines the thickness of the character based on the difference value, determines an adjustment level corresponding to the thickness, and instructs the printing device to adjust the adjustment level. Image quality adjustment device. further comprising specifying means for specifying a character area included in print data for printing the printed matter according to a user's specification;
Claims 10 to 15, wherein the comparing means further compares character information of the reference image and character information of the inspection image data corresponding to the character area specified by the specifying means. The character image quality adjustment device according to any one of the above. The instruction means extracts a comparison result between the character information of the reference image and the character information of the inspection image data corresponding to the character area designated by the designation means to the first extraction means or the second extraction means. The method is characterized in that the parameter is instructed to be adjusted with more emphasis placed on a comparison result between the character information of the reference image and the character information of the inspection image data corresponding to the character area extracted by the means. The character image quality adjustment device according to claim 16. A control method for controlling a character image quality adjustment device that reads a printed matter printed by a printing device and adjusts the character image quality of the printed matter printed by the printing device, the method comprising:
a reading step of reading the printed matter to obtain inspection image data;
A first extraction step of analyzing PDL data of print data for printing the printed material to determine whether or not it includes a character attribute, and if the character attribute is included, extracting a character area corresponding to the character attribute;
If the first extraction step determines that the character attribute is not included, the image data obtained by rendering the print data is analyzed to determine whether the character attribute is included, and if the character attribute is included, the image data obtained by rendering the print data is analyzed. a second extraction step of extracting a character region corresponding to the character attribute;
a comparison step of comparing the character information of the reference image and the character information of the test image data corresponding to the character area extracted in the first extraction step or the second extraction step;
an instructing step of instructing the printing device to adjust parameters of a printing process according to the comparison result of the comparison step;
A control method characterized by having the following. A program for causing a computer to execute each step of the control method according to claim 18.

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