JP4004312B2 - Image data processing device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image data processing apparatus, more specifically, an optical printer such as a laser printer, a digital copying machine, an image data processing apparatus using an electrophotographic system for processing digital image data such as a plain paper fax machine, or the like. The present invention relates to an image processing apparatus applied to an image display apparatus.
[0002]
[Prior art]
Conventionally, in the invention described in, for example, Japanese Patent Laid-Open No. 5-207282, in order to improve image quality by correcting contour line jaggies for image data developed in a bitmap shape, it is stored in advance in a memory. The data that needs to be stored is reduced as much as possible, and the determination of the correction data for the pixels that need correction and the determination of the correction data for the pixels that need correction in the image data is extremely short by simple determination and calculation by a microprocessor or the like. The ability to do it in time is achieved by the method described below.
[0003]
That is, the image data processing method for achieving the above contents recognizes the line segment shape of the boundary between the black pixel region and the white pixel of the image data expanded in a bitmap shape, and performs the required processing for each pixel. Replace the recognized line segment features with multi-bit code information, determine whether or not the pixel needs to be corrected using at least part of the code information, and Performs correction according to the code information.
[0004]
On the other hand, an image data processing apparatus according to this image data processing method has a window for extracting data of each pixel in a predetermined area centered on a target pixel of image data expanded in a bitmap shape, and extracts through the window. A multi-bit code representing the shape of the line segment shape recognized for the target pixel by recognizing the line segment shape of the boundary between the black pixel region of the image data and the white pixel in the image data A pattern recognition unit that generates information, a determination unit that determines whether or not the pixel needs to be corrected using at least a part of the code information, and a pixel that is determined to be corrected by the unit, A correction data memory that reads out and outputs correction data stored in advance using the code information generated by the pattern recognition means as an address. It was those.
[0005]
Here, the pattern recognition means, as code information representing the feature of the line segment shape recognized for each predetermined pixel, a code indicating whether the pixel to be subjected to pattern recognition is a black pixel or a white pixel, Generates code information including a code indicating the inclination direction of the line segment, a code indicating the degree of inclination, and a code indicating the position from the pixel at the end of the line segment continuous in the horizontal or vertical direction of the target pixel. It was a thing.
[0006]
Then, according to the image data processing method and apparatus described above, the line segment shape of the boundary portion (the contour line of a character, etc.) with the white pixel of the black pixel region of the image data expanded in a bitmap shape is recognized. Then, replace each required pixel with code information of a plurality of bits, determine whether or not the pixel needs correction by using at least a part of the code information, and for the pixel that needs correction Since correction according to the code information is performed, it is not necessary to create and store in advance all feature patterns that need correction as templates, and correction data for pixels that need to be corrected and need correction It has been possible to easily determine this in a short time using the code information.
[0007]
In addition, as an example, white pixels that are one line above or one line below the black pixels in the horizontal line that have been determined as pixels that do not need to be corrected by the determination unit (that is, among the image data expanded in the form of a bitmap, By adding correction data substantially smaller than 1 pixel to a pixel area and a white pixel area but white pixels that are not pixels constituting a hatched line segment with jaggy), a bitmap shape The line width in the sub-scanning direction of the horizontal line segment is increased without losing the shape of the image data developed in the image data, and the line width ratio of the vertical line segment and the horizontal line segment in the electrophotographic image data processing apparatus is made uniform ( Line width ratio → vertical line segment: horizontal line segment = 1: 1).
[0008]
[Problems to be solved by the invention]
As described above, in the prior art, the line width in the sub-scanning direction of the horizontal line segment is thickened without losing the shape of the image data developed in a bitmap shape, and the vertical line segment in the electrophotographic image data processing apparatus is The line width ratio of the horizontal line segment can be made uniform (line width ratio → vertical line segment: horizontal line segment = 1: 1).
[0009]
However, when thickening the line width in the sub-scanning direction of the horizontal line segment, as described above, the white pixel on one line or one line below the horizontal line segment black pixel is substantially more than one pixel. Small correction data is added at equal intervals for each pixel. When this thickening is actually used as a signal for driving a light source such as a laser in an electrophotographic image data processing apparatus, a signal representing a black pixel in a horizontal line is a continuous change in driving signal for a plurality of pixel periods. Therefore, the signal representing the correction data of the white pixel one line above or one line below the horizontal line black pixel is accompanied by a change in the drive signal that changes in the pixel cycle. This was one of the factors that generated (EMI).
[0010]
In the present invention, a new method is proposed for thickening the line width in the sub-scanning direction of the horizontal line segment in the image data processing apparatus using the electrophotographic method, and the shape of the image data developed in a bitmap shape is not lost as much as possible. It is another object of the present invention to improve the degree of freedom of thickening the line width in the sub-scanning direction of the horizontal line segment and to minimize the influence of electromagnetic noise generated from the image data processing apparatus.
[0011]
Specifically, the first object of the present invention is to increase the line width in the sub-scanning direction of the horizontal line segment without impairing the shape of the image of the image data expanded in the form of a bitmap, and to obtain image data by electrophotography. The object is to make the line width ratio of the vertical line segment and horizontal line segment uniform in the processing apparatus.
[0012]
In addition to the first object, the second object simplifies the extraction of pixels to be subjected to thickening of the line width in the sub-scanning direction of the horizontal line by the image data processing device, and improves the efficiency of creating image correction data. Its purpose is to plan.
[0013]
In addition to the first and second objects, the third object is to allow the user to select whether or not to thicken the line width in the sub-scanning direction of the horizontal line in the electrophotographic image data processing apparatus. The object is to facilitate the confirmation of the thickening effect of the line width in the sub-scanning direction of the horizontal line segment.
[0014]
[Means for Solving the Problems]
According to the first aspect of the present invention, main scanning M pixels × sub-scanning N lines (M and N are used for extracting data of each pixel in a predetermined region centering on a pixel as a target of image data expanded in a bitmap shape. The line segment shape of the boundary portion between the window means (both integer) and the white pixel of the black pixel area of the image data extracted through the window means, and the recognition is performed for the pixel as the object of the image data. A pattern recognition unit that generates code information of a plurality of bits representing the characteristics of the line segment shape, and when the line segment shape recognized by the pattern recognition unit is selectively corrected and thickened, the line segment shape is A determination unit that determines whether or not a constituent pixel is a pixel to be thickened using at least a part of the code information, and a pixel that has been determined to be a thick line by the determination unit, An image data processing apparatus comprising: memory block means for reading out and outputting correction data stored in advance according to the code information generated by the pattern recognition means as an address, and developing the bitmap data A sub-scan counting unit that counts the number of lines in the sub-scanning direction of the image data that has been detected is determined as a pixel to be thickened by the determination unit, and the pixel is on one line of black pixels in a horizontal line segment Alternatively, in the case of multi-bit code information indicating a white pixel below one line, a plurality of bits other than the part of the code information used for discrimination of the pixel to be thickened by the discrimination means. A plurality of bits of code information generated by a plurality of bits counted from the sub-scan count means And the correction data corresponding to the address is read out from the memory block and output.
[0015]
According to a second aspect of the present invention, in the first aspect of the present invention, there is provided sub-scanning count setting means for repeating a preset count value as the count value of the number of lines in the sub-scanning direction counted by the sub-scanning counting means. It is characterized by that.
[0016]
According to a third aspect of the present invention, in the first or second aspect of the present invention, the determination unit determines that the pixel is a target for thickening, and the pixel is one line below or one line below the horizontal line black pixel. When it is a multi-bit code information indicating that it is a white pixel, the multi-bit code information other than the part of the code information used for the determination of the pixel to be thickened by the determination means Code information replacement means for selecting whether or not to replace with multi-bit code information generated by the multi-bit sub-scan count value output from the sub-scan count means is provided, and the code information from the code information replacement means is An address is used, and correction data corresponding to the address is read from the memory block and output.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an image data processing apparatus according to the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a block diagram showing a digital copying machine to which a printing control unit, which is an embodiment of an image data processing apparatus according to the present invention, is applied. In the figure, 1 is a digital copying machine, and the digital copying machine 1 is An image reading unit 2, a signal processing unit 3, and an image printing unit 4. FIG. 2 is a block diagram for explaining the print control unit shown in FIG. 1 in detail. The print control unit includes a first temporary storage unit 31, an image processing unit 32, and a second temporary storage unit 33.
[0018]
A digital copying machine 1 shown in FIG. 1 shows a one-beam system, and an image reading unit 2 that roughly reads a document (not shown), and various processes for image data read by the image reading unit 2. The signal processing unit 3 for performing the above and the image printing unit 4 for printing an image on a printing paper (not shown) by a known electrophotographic method based on the image data processed by the signal processing unit 3.
[0019]
More specifically, in the image reading unit 2, the document placed on the contact glass 5 is irradiated by the light source 6 that is elongated in the main scanning direction, and the reflected light thereof is the first mirror 7, the second mirror 9, and the third mirror 10. Are sequentially reflected, then imaged by the imaging optical system 12 and photoelectrically converted by a CCD (Charge Coupled Device) sensor 13. In this case, the light source 6 and the first mirror 7 constitute the first scanning unit 8, the second mirror 9 and the third mirror 10 constitute the second scanning unit 11, and the first scanning unit 8 and the second scanning unit 11. Moves at a speed ratio of 2 to 1, whereby the document is scanned in the sub-main scanning direction.
[0020]
In the signal processing unit 3, the analog image signal photoelectrically converted by the CCD sensor 13 is amplified by an amplifier 14 and then converted into a digital image signal by an A / D converter (ADC) 15. Next, the digital image signal is subjected to image processing such as lightness correction processing, scaling processing, and editing processing by the image processing unit 16, and then the raster image data subjected to image processing by the image processing unit 16 is smoothed by the print control unit 18. It is processed and converted into image data for one beam (one line). The LD modulation unit 19 modulates the beam of one semiconductor laser of the LD unit 20 based on the image data for one line. A circuit that limits the image range or performs pattern synthesis may be provided between the print control unit 18 and the LD modulation unit 19.
[0021]
In the image printing unit 4, one beam emitted from the LD unit 20 is converged by the cylinder lens 22, and then the one beam deflected at a constant angular velocity by the polygon mirror 23 is corrected to a uniform velocity deflection by the fθ lens 24. The photosensitive drum 26 is irradiated to form a latent image for one line and is detected by the light detector 27. The photodetector 27 is disposed in front of the effective writing area in the main scanning direction, receives the beam, and feeds back the synchronization detection pulse signal XDETP to the print controller 18. Although the case where a semiconductor laser that generates one laser beam is used is described here, the number of beams is not limited to one, and a semiconductor laser array having a plurality of beams may be used.
[0022]
Here, the print control unit 18 also adjusts the input speed of the image data input from the image reading unit 2 and the output speed of outputting the image data to the image printing unit 4. That is, in the image reading unit 2, the original on the contact glass 5 is scanned in the sub scanning direction by the first scanning unit 8 and the second scanning unit 11 and read by the CCD sensor 13, so that the CCD sensor 13 continues in the sub scanning direction. The image data of the dot matrix of the plurality of main scanning lines is output to the signal processing unit 3 line by line.
[0023]
At this time, the CCD sensor 13 resets the address of the image data for one line by the line synchronization signal LSYNC, and then outputs one pixel at a time in the main scanning direction for each pixel clock. 18) is output line by line at a predetermined line period based on the scanning speed of the first scanning unit 8 and the second scanning unit 11, the reading period of the CCD sensor 13, and the like. In the image printing unit 4, when the laser beam scanned by the polygon mirror 23 enters just before the photosensitive drum 26, the light detector 27 outputs the synchronization detection pulse signal XDETP, and the print control unit 18 detects this synchronization detection. Print timing is controlled based on the pulse signal XDETP.
[0024]
The print control unit 18 performs a smoothing process. Here, the matrix necessary for smoothing is, for example, a total of 9 lines including 4 lines before and after the target pixel. As shown in FIG. 2, first, image data for nine lines in the form of a dot matrix from the image processing unit 16 is sequentially stored in the first temporary storage unit 31 for each pixel in synchronization with the first pixel clock. The The present invention can also be applied to the case where the image data from the previous stage is parallel data in which a plurality of data per clock is input via a plurality of signal lines. In this case, parallel-to-serial conversion is performed. Nine lines of image data are stored in the first temporary storage means 31.
[0025]
The image data for nine lines stored in the first temporary storage means 31 is read simultaneously for nine lines in synchronization with the second pixel clock while the image data for one line is input. Here, as an example, a case where the second pixel clock reads image data in units of one pixel for each line of nine lines from the first temporary storage unit 31 will be described.
[0026]
FIG. 3 is a diagram illustrating an example of a timing chart in the image data reading operation in units of one pixel by the second pixel clock from the first temporary storage unit 31. Nine lines of image data for nine lines read from the first temporary storage means 31 are simultaneously output by the image processing means 32 using a window shown in FIG.
[0027]
The image processing means 32 generates a matrix based on these nine lines and extracts features of the pixel of interest based on the values of the pixel of interest and the surrounding pixels in order to reduce the diagonal lines at the edge of the image and the jagged edges of the arc. Determine the value of the pixel of interest. Further, the image processing means 32 performs this smoothing process every second pixel clock, thereby converting all the pixels into multi-value data of a plurality of bits per pixel.
[0028]
The multi-value data output from the image processing means 32 is transferred to the second temporary storage means 33 in synchronization with the second pixel clock, and input address signals to the memory constituting the second temporary storage means 33. Used as. Further, image data corresponding to the input address signal converted into multi-value data of a plurality of bits for each pixel is read from the second temporary storage means 33 in synchronization with the second pixel clock.
[0029]
4, 5, and 6 are block diagrams illustrating a schematic configuration example of the image processing unit 32 illustrated in FIG. 2, and FIG. 7 is a window that is a main part of the image processing unit illustrated in FIGS. 4 to 6. It is a figure which shows the 40 specific example of a structure. As shown in FIG. 4, the basic configuration of the image processing means 32 includes a window 40, a pattern recognition unit 41, a memory block 42, a video data output unit 43, and a timing control unit 44 that controls these synchronously. In the window 40 shown in FIG. 7, shift registers 40a to 40i for 13 pixels are serially connected in the main scanning direction to the image data for 9 lines output from the first temporary storage unit 31 shown in FIG. To form a pattern detection window.
[0030]
However, as described above, the image data for 9 lines read from the first temporary storage means 31 is sequentially output to the image processing means 32 for 13 pixels from the head of each line. Regarding the window 40 constituting the image processing means 32, the pixel position of the seventh pixel from the left end of the shift register 40e as shown in FIG. 7 (shown by hatching in FIG. 7) is the storage position of the target pixel as the target. Become. Subsequently, the image data is sequentially shifted one pixel at a time in the shift registers 40a to 40i constituting the window 40 arranged for the image processing means 32, whereby the target pixel is sequentially changed with respect to the image processing means 32, It becomes possible to continuously extract the image data of the window 40 centered on the target pixel.
[0031]
FIG. 8 is a diagram showing a state in which the image data is sequentially shifted one pixel at a time in the shift registers 40a to 40i constituting the window 40 arranged for the image processing means 32. As shown in FIG. FIG. 8A shows the window 40 shown in FIG. 7 at an arbitrary rising edge (at time T1 in the drawing) of the second pixel clock for the image data input from the image processing unit 16 shown in FIG. The image data in the shift registers 40a to 40i configuring the above is shown. Next, FIG. 8B shows the window 40 shown in FIG. 7 at the time of the rising edge of the second pixel clock (at time T2 in the figure) that comes after an arbitrary rising edge of the second pixel clock. The image data in the shift registers 40a-40i which comprise is shown.
[0032]
The operation shown in FIG. 8, that is, the image processing means 32 starts from the head of each line by sequentially shifting the image data in the shift registers 40a to 40i constituting the window 40 by one pixel every second pixel clock. Dot information is extracted with all pixels as the target pixel.
[0033]
Based on the dot information extracted for the pixel of interest in the window 40, the pattern recognition unit 41 recognizes the target pixel (target pixel) and its surrounding information, particularly the boundary between the black pixel and the white pixel of the image data. This is a block that recognizes the characteristics of the line segment shape and outputs the recognition result as code information in a predetermined format. The code information output from the pattern recognition unit 41 becomes a memory read address during image processing (smoothing) of the memory block 42.
[0034]
FIG. 9 is a block diagram illustrating an example of the internal configuration of the pattern recognition unit 41 and the relationship with the window 40. The window 40, which is a sample window, includes a central 3 × 3 bit core area (Core) 40C, an upper area (Upper) 40U, a lower area (Down) 40D, a left area (Left) 40L, and a right area (Right). 40R. However, the details thereof are the same as those described in Japanese Patent Application No. 3-314828 and Japanese Patent Application No. 4-301395, and therefore detailed description thereof is omitted here.
[0035]
Further, the pattern recognition unit 41 includes a core region recognition unit 411, a peripheral region recognition unit 412, multiplexers (MUX) 413 and 414, a gradient calculation unit 415, a position calculation unit 416, a determination unit 417, and a gate 418. The peripheral region recognition unit 412 is further configured by an upper region recognition unit 412U, a right region recognition unit 412R, a lower region recognition unit 412D, and a left region recognition unit 412L. Since the operation of each part is the same as that described in Japanese Patent Application No. 3-314828 and Japanese Patent Application No. 4-301395, detailed description thereof is omitted here.
[0036]
FIG. 10 is a diagram for explaining a specific configuration example and operation of the memory block 42. The configuration example shown in FIG. 10A is the same as the contents described in Japanese Patent Application Nos. 3-314928 and 4-301395, and the memory block 42 includes only the pattern memory 421, and pattern recognition is performed. Using the code information (12 bits) output from the unit 41 as an address, correction data (10 bits) stored in advance is read out, and image data for laser driving is output, which becomes a corrected dot pattern.
[0037]
Further, in the prior art, a white pixel that is one line above or one line below the black pixel of the horizontal line segment that is determined as a pixel that does not need correction by the determination unit 417 illustrated in FIG. 9 (that is, an image developed in a bitmap shape). Among the data, the boundary between the black pixel region and the white pixel region, but the white line pixel that is not the pixel that constitutes the hatched line segment with jaggy) Replace bits with unique values.
[0038]
As shown in FIG. 10B, the code information of all 12 bits output from the pattern recognition unit 41 is A0 to A11. Of these, the bit indicating the inclination direction of the line segment is A11, and the bit for determining whether the pixel needs to be corrected by the determination unit 417 is A10, A9 (however, the necessity determination target here means jaggy correction) ). In addition, a bit indicating which transition position of the boundary region between the black pixel and the white pixel is a pixel to be subjected to pattern recognition is A8, and a bit which indicates whether the pixel to be pattern recognition is a black pixel or a white pixel. A7, bits indicating the degree of inclination A6, A5, A4, a bit indicating whether the pixel targeted for pattern recognition is one pixel or a line segment having a width of 2 pixels or more, A3, horizontal of the target pixel Alternatively, the bits indicating the position from the pixel at the end of the line segment continuous in the vertical direction are A2, A1, and A0.
[0039]
11, 12, and 13 are diagrams for explaining an example of an array image of corrected image data at the time of thickening a horizontal line. When this is done, (A10, A9) = (1, 1) indicates code information of pixels that do not need correction, and (A2) = (0) indicates that the pixel to be pattern-recognized is a horizontal line segment black When indicating that the pixel is a white pixel one line above or one line below, (A1, A0) = (0, 0) is replaced, and the correction data stored in advance for the white pixel is replaced with one pixel. By substituting substantially small black pixel data or black pixel data for one pixel, the image data expanded in the form of a bitmap is sub-scanned in the horizontal line without impairing the shape of the image as shown in FIG. By making the line width thicker, the line width ratio of the vertical line segment and the horizontal line segment in the electrophotographic image data processing apparatus can be made uniform (line width ratio → vertical line segment: horizontal line segment = 1: 1). . Further, lines 2, 7, and 12 shown in FIG. 11 indicate the lines subjected to the thickening process. When these lines are printed, an operation with a signal change of a certain period in the figure is performed. Will be done. Therefore, since this signal change is a change at a constant frequency, there is a high possibility that the result will be accompanied by radiation noise at a constant frequency.
[0040]
The radiation noise is one type of electromagnetic noise (EMI) generated from electronic equipment, and propagates through space. In addition to radiation noise, there is conduction noise that propagates through cables and the like. These electromagnetic noises cause interference with devices such as televisions and radios and cause other electronic devices to malfunction, so their generation levels are legally regulated. In this image data processing apparatus, the signal waveform has a constant frequency by performing an operation with a signal change of a constant period as in this example, and the generation level of the radiation noise becomes high at this constant frequency.
[0041]
In the present invention, when the line shape recognized by the pattern recognition unit 41 is selectively corrected and thickened, the pixels constituting the line shape by the determination unit 417 are pixels to be thickened (correction). Is a white pixel that is one line above or one line below the black pixel in the horizontal line segment that is determined to be an unnecessary pixel (that is, at the boundary between the black pixel region and the white pixel in the image data developed in a bitmap shape). The image processing means 32 shown in FIG. 5 has some bits of code information of a plurality of bits representing the feature of the line segment shape for white pixels that are not included in the hatched line segment with jaggy. This is replaced with the count value of the number of lines in the sub-scanning direction output from the sub-scanning counting unit 45.
[0042]
As shown in FIG. 10B, all 12-bit code information output from the pattern recognition unit 41 is A0 to A11. Of these, the bit indicating the inclination direction of the line segment is A11, and the bit for determining whether the pixel needs to be corrected by the determination unit 417 is A10, A9 (however, the necessity determination target here means jaggy correction) ).
[0043]
In addition, a bit indicating which transition position of the boundary region between the black pixel and the white pixel is a pixel to be subjected to pattern recognition is A8, and a bit which indicates whether the pixel to be pattern recognition is a black pixel or a white pixel. A7, bits indicating the degree of inclination A6, A5, A4, a bit indicating whether the pixel targeted for pattern recognition is one pixel or a line segment having a width of 2 pixels or more, A3, horizontal of the target pixel Alternatively, the bits indicating the position from the pixel at the end of the line segment continuous in the vertical direction are A2, A1, and A0.
[0044]
In this case, (A10, A9) = (1, 1) indicates code information of pixels that do not need correction, and (A8, A7) = (0, 0) is a pixel that is a pattern recognition target. 5 indicates that the white pixel is one pixel above or one pixel below the horizontal line segment black pixel, the code information replacement means 46 shown in FIG. 5 counts A1 and A0 as the number of lines in the sub-scanning direction. By replacing the correction data stored in advance with respect to the white pixel for each sub-scanning line with the black pixel data substantially equivalent to one pixel or the black pixel data for one pixel for each sub-scanning line As shown in FIG. 12, the image data expanded in the shape is thickened in the sub-scanning line width of the horizontal line without impairing the shape of the image, and the vertical line in the electrophotographic image data processing apparatus is obtained. Horizontal uniformity of the line width ratio of the line segment (line width ratio → vertical line: Horizontal line 1: 1) is possible. Further, lines 2, 7, and 12 shown in FIG. 12 indicate the lines subjected to the thickening process, but when these lines are printed, they are constant even when compared with the signal waveform shown in FIG. An operation involving a signal change having a period and a phase different from the period and the constant phase is performed. (In this example, line 2, line 7, and line 12 each have a signal change with a different period and phase.)
[0045]
The signal change described above is not a significantly different period (frequency change), but it is a change that is not a constant frequency and a constant phase, so there is no radiation noise at a constant frequency, and the noise level at each frequency is a constant frequency. Lower than the noise level in the case of signal change. This is because the signal waveform is distributed to different frequencies by performing operations with signal changes with different periods, and as a result, the generation level due to the above-mentioned radiation noise can be dispersed. The noise level can be reduced to less than the noise level, and the noise level can be reduced as the dispersion period is increased.
[0046]
Up to this point, the case where the present invention is applied to the thickening of the line width in the sub-scanning direction of the horizontal line segment in the image data processing apparatus has been described as a representative example. However, the present invention is directed to the thickening of the line width in the vertical line segment. The same applies to.
[0047]
Furthermore, when the count value of the sub-scanning counting unit 45 shown in FIG. 5 is set to 2 bits in advance, the count value is a repetition of 0 → 1 → 2 → 3 → 0 → 1 → 2 → 3. As shown in FIG. 13, the image data expanded in the form of a bitmap can be made thicker in the width of the horizontal line in the sub-scanning direction without impairing the shape of the image, and the creation of image correction data can be simplified. It becomes possible. Also in this case, as in the signal waveform shown in FIG. 12, the lines 2, 7, and 12 shown in FIG. 13 indicate the lines subjected to the thickening process. When these lines are printed, FIG. Although the period is not as irregular as the signal waveform shown in FIG. 11, the operation is not a constant period but a signal change with a different period compared to the signal waveform shown in FIG. 11. (In this example, line 2 and line 12 have the same period and phase, and only line 7 has a signal change with a different period and phase.) Therefore, this signal change is not a significantly different period, but a constant frequency and a constant. Since the phase is not a phase change, there is little possibility of a result accompanied by radiation noise at a constant frequency, and the combination of correction pixel types is smaller than the signal waveform shown in FIG.
[0048]
Next, as shown in FIG. 6, a code information replacement unit 46 is further provided for the image processing unit 32, and the code information replacement unit 46 selects whether or not to replace the code information A1 and A0. Make it possible. Thus, whether to print an image (not shown) in which the line width in the sub-scanning direction of the horizontal line segment is not thickened, or to print an image in which the line width of the horizontal line segment in the sub-scanning direction is thickened Selection is also possible.
[0049]
FIG. 14 is a diagram showing a specific example of a circuit in the code information replacing unit 46. 14, an image (not shown) in which the line width in the sub-scanning direction is not increased is printed or the line width in the sub-scanning direction is increased. Select whether to print the image that has been processed.
[0050]
The smoothing correction data stored in advance in the memory block 42 of the image processing means 32 corresponds to the code information from the pattern recognition unit 41 in the memory block 42 before image processing (smoothing) is performed on the image data. Data must be set. The correction data setting I / F can be handled by writing data stored in a built-in memory arranged in the image forming apparatus system by the CPU.
[0051]
According to the embodiment of the memory block 42 shown in FIG. 10, the correction data output is information (in this case, binary) in which the laser emission time is divided into a plurality of main scanning one pixel widths for each pixel of the input image data. PWM signal output) or multi-value information is output from the second temporary storage means 33 shown in FIG. 2. Even at this time, the correction data output is equivalent to one pixel for each second pixel clock. It will be output one by one.
[0052]
The correction data output that is output by one pixel every second pixel clock is finally input to the image data conversion means and output as an output converted into the image data format for one pixel as described above. The data is output to the modulation unit 19, and the image data is written on the photosensitive drum 26 by ON / OFF of the LD of the LD modulation unit 19 and power control.
[0053]
Here, an additional description of the image processing means 32 shown in FIGS. 4 to 6 will be described below. The timing control unit 44 includes an FGATE signal that defines a writing period for one page of image data in the sub-scanning direction, an LGATE signal that defines a writing period for one main scanning line, and an LSYNC that indicates the writing start and end timing of each line. When an image clock WCLK and a RESET signal that take a read / write cycle for each signal are input, it is necessary to synchronize the operations of the respective blocks 40 to 42 shown in FIGS. Generates a clock signal and the like.
[0054]
The correction data in the memory block 42 can be selectively loaded from a storage means such as a ROM by an MPU or CPU in the image forming apparatus system, or can be downloaded from a host computer. It is possible to easily change the correction data for the pattern to be corrected.
[0055]
Further, in addition to the contents described above, the details of the following contents are the same as the contents described in Japanese Patent Application No. 3-314828 and Japanese Patent Application No. 4-301395, and are omitted here.
(1) Region division of window for matching and its detection pattern and use region (2) Output signal from each block constituting pattern recognition unit 41 shown in FIGS. 4 to 6 (3) FIG. (4) Regarding the dot correction method (4) Regarding the action of each block in the pattern recognition unit 41 shown in FIG.
【The invention's effect】
As described above, according to the present invention, the following actions and effects can be obtained with respect to the contents of each claim.
According to the present invention, the line width in the sub-scanning direction of the horizontal line segment is thickened without impairing the shape of the image data developed in the form of a bitmap, and the vertical line segment and the horizontal line segment in the electrophotographic image data processing apparatus. The line width ratio can be made uniform.
[0057]
Further, it is possible to simplify the extraction of pixels to be thickened in the line width in the sub-scanning direction by the image data processing apparatus, and to improve the efficiency of creating image correction data.
[0058]
In addition, it is possible to select whether or not to increase the line width in the sub-scanning direction of the horizontal line in the electrophotographic image data processing apparatus, and confirm the effect of increasing the line width in the sub-scanning direction by the user. Can be made easier.
[Brief description of the drawings]
FIG. 1 is a configuration diagram illustrating a digital copying machine to which a print control unit, which is an embodiment of an image data processing apparatus according to the present invention, is applied.
FIG. 2 is a block diagram for explaining in detail a print control unit shown in FIG. 1;
FIG. 3 is a diagram showing an example of a timing chart in an operation of reading image data in units of one pixel by a second pixel clock from a first temporary storage unit.
4 is a block diagram illustrating a schematic configuration example of an image processing unit illustrated in FIG. 2;
5 is a block diagram illustrating a schematic configuration example of an image processing unit illustrated in FIG. 2. FIG.
6 is a block diagram illustrating a schematic configuration example of an image processing unit illustrated in FIG. 2;
7 is a diagram illustrating a specific configuration example of a window which is a main part of the image processing unit illustrated in FIGS. 4 to 6; FIG.
FIG. 8 is a diagram showing a state in which image data is sequentially shifted one pixel at a time in a shift register that constitutes a window arranged for the image processing means.
FIG. 9 is a block diagram illustrating an example of the internal configuration of a pattern recognition unit and a relationship with a window.
FIG. 10 is a diagram for explaining a specific configuration example and operation of a memory block;
FIG. 11 is a diagram for explaining an example of an array image of corrected image data when a horizontal line is thickened;
FIG. 12 is a diagram for explaining an example of an array image of corrected image data when a horizontal line is thickened.
FIG. 13 is a diagram for explaining an example of an array image of corrected image data when a horizontal line is thickened.
FIG. 14 is a diagram showing a specific example of a circuit in code information replacing means.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Digital copying machine, 2 ... Image reading part, 3 ... Signal processing part, 4 ... Image printing part, 5 ... Contact glass, 6 ... Light source, 7 ... 1st mirror, 8 ... 1st scanning unit, 9 ... 2nd Mirror, 10 ... third mirror, 11 ... second scanning unit, 12 ... imaging optical system, 13 ... CCD sensor, 14 ... amplifier, 15 ... A / D converter, 16 ... image processing unit, 18 ... printing control unit , 19 ... LD modulation unit, 20 ... LD unit, 22 ... cylinder unit, 23 ... polygon mirror, 24 ... fθ lens, 26 ... photoconductor drum, 27 ... photodetector, 31 ... first temporary storage means, 32 ... Image processing means 33 ... second temporary storage means 40 ... window 40U ... upper area 40D ... lower area 40L ... left area 40R ... right area 40C ... core area 41 ... pattern recognition unit 42 ... Memory block, 43 Video data output unit 44 ... Timing control unit 45 ... Sub-scanning counting unit 46 ... Code information replacement means 411 ... Core region recognition unit 412 ... Peripheral region recognition unit 412U ... Upper region recognition unit 412R ... Right region Recognizing unit, 412L: Left region recognizing unit, 412D: Lower region recognizing unit, 413, 414 ... MUX, 415 ... Inclination calculating unit, 416 ... Position calculating unit, 417 ... Discriminating unit, 418 ... Gate, 421 ... Pattern memory.

Claims (3)

Window means of main scanning M pixels × sub-scanning N lines (M and N are both integers) for extracting the data of each pixel in a predetermined area centering on the target pixel of the image data developed in the form of a bitmap , Recognizing the line segment shape of the boundary portion between the black pixel region and the white pixel of the image data extracted through the window means, and determining the feature of the recognized line segment shape for the target pixel of the image data. Pattern recognition means for generating multi-bit code information to be represented, and when the line shape recognized by the pattern recognition means is selectively corrected and thickened, the pixels constituting the line segment shape are thickened. A determination unit that determines whether or not the pixel is a target pixel by using at least a part of the code information; and a pixel that is determined as a thickening target by the determination unit. In the image data processing apparatus comprising: memory block means for reading out and outputting correction data stored in advance according to the address, the code data generated by Sub-scanning counting means is provided for counting the number of lines in the sub-scanning direction, and the discrimination means discriminates the pixel to be thickened, and the pixel is one line below or one line below the horizontal line black pixel. Multi-bit code information other than the part of the code information used for the determination of the pixel to be thickened by the determination means, Replace with the multi-bit code information generated by the multi-bit count value output from the sub-scanning counting means, and An image data processing apparatus which reads out and outputs correction data corresponding to an address from the memory block using the changed code information as an address. 2. The image data processing according to claim 1, further comprising sub-scan count setting means for repeating a count value set in advance for a count value of the number of lines in the sub-scan direction counted by the sub-scan count means. apparatus. When it is determined by the determination means that the pixel is a pixel to be thickened, and the pixel is multi-bit code information indicating that the pixel is a white pixel on one line or one line below the horizontal line black pixel The multi-bit code information other than the part of the code information used for the determination of the pixel to be thickened by the determination unit is based on the multi-bit sub-scan count value output from the sub-scan count unit. Code information replacement means for selecting whether or not to replace the generated multi-bit code information is provided, and the code information from the code information replacement means is used as an address, and correction data corresponding to the address is read from the memory block 3. The image data processing apparatus according to claim 1, wherein the image data processing apparatus outputs the image data.

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