Image forming apparatus for outputting a halftone image and image forming method

An image forming method being configured to execute halftone processing using a dithering matrix on input image, output a halftone image, perform correction on the halftone image to shift a pixel at a correction position, and generate an image with a converted lower resolution based on the corrected image, wherein the matrix includes a plural sub-matrices, wherein an arrangement of a threshold in a first sub-matrix is configured to form a first halftone dot having a first line shape for an input image with a predetermined density, wherein an arrangement of a threshold in a second sub-matrix is configured to form a second halftone dot with the same angle as the first line shape and having a center position different from the first halftone dot for the input image with the predetermined density, and wherein the first and second halftone dot form a line shape with a predetermined screen angle.

BACKGROUND

Field of the Disclosure

The present disclosure generally relates to image forming and, more particularly, to an image forming apparatus and an image forming method.

Description of the Related Art

As a technique for achieving both size reduction and cost reduction in a tandem color image forming apparatus, a technique for correcting image data to cancel distortion resulting from curvature of a main-scan line is proposed. A technique for reproducing an image with a high resolution in a pseudo manner by using a spot-multiplexing technique is proposed. However, if these two techniques are used at the same time, there is a possibility that unevenness occurs in an image on a recording medium. As a technique for improving the unevenness, a method (Japanese Patent Application Laid-Open No. 2017-130751) is discussed in which in a case where two vector components representing the period of a halftone dot in a dithering matrix used for pseudo halftone processing have a combination of even numbers, thresholds are arranged so that the number of pixels in a sub-scanning direction, which constitute a halftone dot, becomes always even. Using this method, unevenness in density of an image on a recording medium can be suppressed without limiting the halftone dot period in the dithering matrix. Therefore, the occurrence of moire between colors can be prevented with less restrictions on the screen ruling and the screen angle of the dithering matrix.

In the technique discussed in Japanese Patent Application Laid-Open No. 2017-130751, the shape of a halftone dot formed with a high resolution in a pseudo manner using a spot-multiplexing technique is reversed in a sub-scanning direction before and after a correction position where image data is corrected so as to cancel distortion resulting from curvature of a main-scan line. Accordingly, the shape of a halftone dot appearing before the correction position is different from the shape of a halftone dot appearing after the correction position. As a result, there is a possibility that unevenness in an image on a recording medium occurs, especially, in an image forming apparatus using a laser scanner (scanning-type optical system).

In the case of executing screen processing, a line shape of a predetermined screen angle is formed of a plurality of halftone dots having different central points and the same screen angle. In this configuration, the line shape slightly fluctuates. This processing makes it difficult to recognize unevenness of an image when correction in the sub-scanning direction is performed before and after the correction position.

SUMMARY

According to one or more aspects of the present disclosure, an image forming apparatus includes a controlling portion having a processor which executes a set of instructions or having a circuitry, the controlling portion being configured to execute halftone processing using a dithering matrix on input image data with a first resolution, and output the image data having been subjected to the halftone processing, perform correction on the image data having been subjected to the halftone processing to shift a pixel in a sub-scanning direction at a correction position in a main-scanning direction, the correction position being determined based on correction information for correcting distortion resulting from curvature of a scan line to form an image according to the output image data, and generate image data with a converted resolution by performing resolution conversion processing on the corrected image data to convert the resolution of the image data from the first resolution to a second resolution lower than the first resolution, wherein the dithering matrix includes a plurality of sub-matrices, wherein an arrangement of a threshold in a first sub-matrix is configured so as to form a first halftone dot having a first line shape for an input image with a predetermined density, wherein an arrangement of a threshold in a second sub-matrix adjacent to the first sub-matrix is configured so as to form a second halftone dot with the same angle as the first line shape and having a center position different from the first halftone dot for the input image with the predetermined density, and wherein the first halftone dot and the second halftone dot form a line shape with a predetermined screen angle in an image having been subjected to the halftone processing, the image being obtained after executing the halftone processing on the input image with the predetermined density by using the first sub-matrix and the second sub-matrix.

DESCRIPTION OF THE EMBODIMENTS

Various exemplary embodiments, features, and aspects of the present disclosure will be described in detail below with reference to the accompanying drawings. The configurations illustrated in the following exemplary embodiments are merely examples, and the present disclosure is not limited to the following exemplary embodiments illustrated in the drawings.

The present exemplary embodiment illustrates an example of a multi-function peripheral (MFP) having a plurality of functions, such as a copy function and a printer function, as a color image forming apparatus.FIG. 1is a block diagram illustrating an example of a configuration of a printing system according to the present exemplary embodiment. The printing system illustrated inFIG. 1includes an MFP100and a personal computer (PC)120. The MFP100and the PC120are connected to each other via a network130such as a local area network (LAN).

The MFP100includes a central processing unit (CPU)101, a memory102, a hard disk drive (HDD)103, a scanner unit104, a printer unit105, a Page Description Language (PDL) processing unit106, a raster image processor (RIP) unit107, an image processing unit108, a display unit109, and a network interface (I/F)110. These units are connected to one another via an internal bus111.

The CPU101, which may include one or more processors, one or more memories, circuitry, or a combination thereof, may collectively control the MFP100. The memory102includes a read-only memory (ROM) that stores various commands (including application programs) executed by the CPU101to control the MFP100and various data, and a random access memory (RAM) that functions as a work area for the CPU101. The HDD103is a large-capacity storage medium that stores various programs, image data, and the like. The scanner unit104optically reads a document that is placed on a platen glass or the like (not illustrated), and acquires image data in bitmap format.

The PDL processing unit106analyzes PDL data included in a print job received from the PC120, and generates a display list (DL) as intermediate data. The generated DL is sent to the RIP unit107. The RIP unit107executes rendering processing based on the received DL and generates contone (multivalued) bitmap image data. The term “contone bitmap image data” refers to image data having an 8-bit or 10-bit depth and multiple gradation levels, representing colors in a color space, such as an RGB color space, and having information on these colors for each discrete pixel. Specifically, drawing bitmap data and attribute bitmap data are generated. Prior to the generation of these pieces of data, the attribute information on a drawing target object is generated for each pixel. The attribute information used in this case is determined in accordance with the following criteria.

In a case of being specified by a character drawing command (character type or character code): text attribute

In a case of being specified by a line drawing command (coordinate point, length, and thickness): line attribute

In a case of being specified by a graphics drawing command (rectangle, shape, and coordinate point): graphics attribute

In a case of being specified by an image drawing command (set of points): image attribute

Based on the attribute information, pixels to be drawn in accordance with the processing resolution of the printer unit105are formed and drawing bitmap data in which information (multivalued) on a color to be drawn in each pixel is input is generated. The present exemplary embodiment is based on the premise that pseudo high-resolution processing for drawing a dot with a resolution (e.g., 1,200 dpi) higher than the resolution (e.g., 600 dpi) of the printer unit105, is performed. Accordingly, the resolution of the drawing bitmap data to be generated in this case is 1,200 dpi. Further, attribute bitmap data storing attribute information for each pixel is generated so as to correspond to each pixel of the drawing bitmap. The generated drawing bitmap and attribute bitmap are temporarily stored in the memory102or the HDD103, or are sent to the image processing unit108.

The image processing unit108performs necessary image processing on the bitmap format image data to be printed corresponding to the print job from the PC120or optically read by the scanner unit104. The image processing unit108will be described in detail below. The bitmap format image data obtained after the image processing is sent to the printer unit105.

The printer unit105forms an electrostatic latent image in such a manner that a laser scanner (not illustrated) irradiates exposure light (laser beam) by an electrophotographic method based on the image data generated by the image processing unit108, and forms a single color toner image by developing the electrostatic latent image. Then, the printer unit105forms a multicolored toner image by superimposing the single color toner images and forms a color image on a recording medium by transferring the multicolored toner image onto the recording medium (sheet) and fixing the multicolored toner image.

The display unit109includes a liquid crystal panel or the like having a touch screen function and on which various kinds of information are displayed. In addition, a user performs various operations and provides various instructions via a screen displayed on the display unit109. The network I/F110is an interface for performing communication, such as transmission and reception of a print job, with the PC120connected via the network130.

The components of the image forming apparatus are not limited thereto. For example, an input unit including a mouse, a keyboard, and the like may be provided for the user to perform various operations, in place of a touch screen. Components may be added appropriately to the configuration of the image forming apparatus, and the configuration may be changed appropriately depending on the intended use or the like thereof.

FIG. 2is a block diagram illustrating an internal configuration of the image processing unit108. The image processing unit108includes a color conversion processing unit201, a halftone processing unit202, a phase transfer processing unit203, and a pseudo high-resolution processing unit204. Each processing unit will be described below. In the present exemplary embodiment, it is assumed a case where the image processing unit108is implemented by a hardware circuit such as an application specific integrated circuit (ASIC). However, the configuration of the image processing unit108is not limited to this configuration. For example, a general-purpose processor, such as the CPU101, and a hardware circuit may cooperate with each other to implement various kinds of image processing. For example, various kinds of image processing can be implemented by a processor such as the CPU101reading a command that configures an image processing program, and executing the command.

The color conversion processing unit201performs color conversion processing for converting a color space of input image data into a color space supported by the printer unit105. In a case where the printer unit105is a four-color four-drum tandem printer unit that uses toner of four colors in total, i.e., cyan (C), magenta (M), yellow (Y), and black (K), the color space is converted into a CMYK color space.

The halftone processing unit202performs halftone processing by dithering for each color screen for the image data whose color space has been converted into the color space supported by the printer unit105. Dithering uses a threshold matrix (dithering matrix) in which different thresholds are arranged within a matrix having a predetermined size. The halftone processing unit202sequentially develops the dithering matrix on the multivalued bitmap data, which is input image data, in the form of tile and compares a threshold with an input pixel value. If the result of the comparison indicates that the input pixel value is greater than the threshold, and the halftone processing unit202turns on the pixel, and if the result of the comparison indicates that the input pixel value is less than or equal to the threshold, the halftone processing unit202turns off the pixel, thereby representing a halftone image. By the halftone processing, the input image data with continuous gradation (multivalued bitmap data) is converted into halftone image data (binary bitmap data) with area gradation made up of halftone dots. Different dithering matrices for each color screen may be used. The present exemplary embodiment is characterized by dithering matrices as described in detail below.

The phase transfer processing unit203performs line shift processing to shift the line of the image data (in this case, binary bitmap data) obtained after the halftone processing in the sub-scanning direction, thereby correcting the deviation (curvature) of a laser beam scan line of each color of CMYK. This line shift processing is also referred to as “phase transfer processing”.FIGS. 3A and 3Beach illustrate an example of curve characteristics of a scan line of a laser beam. A curve301illustrated inFIG. 3Aindicates characteristics in a case where the laser beam scan line deviates in the upward direction of the sub-scanning direction (conveyance direction of a sheet) as the laser beam scan line advances in a main-scanning direction. A curve302illustrated inFIG. 3Bindicates characteristics in a case where the laser beam scan line deviates downward in the sub-scanning direction as the laser beam scan line advances in the main-scanning direction. InFIG. 3AandFIG. 3B, a straight line300indicates ideal characteristics of the scan line in a case where a scan is performed in a direction perpendicular to the sub-scanning direction, which does not deviate in the sub-scanning direction as the laser beam scan line advances in the main-scanning direction.FIG. 4Aillustrates curve characteristics (amount of deviation) of the laser beam scan line, and a curve401indicates the curve characteristics of the laser beam corresponding to the main-scanning width. On the other hand,FIG. 4Billustrates an amount of correction (correction characteristics) at the time of correcting the curve characteristics illustrated inFIG. 4A. As can be seen fromFIGS. 4A and 4B, the correction characteristics indicated by a curve402are opposite characteristics that cancel out the curve characteristics of the curve401.

FIGS. 5A and 5Beach illustrate an example of specific correction values (correction data) that are used in the phase transfer processing. InFIG. 5A, the vertical axis represents the amount of correction and the horizontal axis represents the pixel position in the main-scanning direction. InFIG. 5A, each of P1, P2, . . . , Pn indicates a point (transfer point) at which the scan line deviates by one pixel in the sub-scanning direction due to the above-described curve characteristics. The pixel position of the transfer point in the main-scanning direction is also referred to as a “transfer position” or “correction position”.FIG. 5Billustrates the direction in which the scan line up to the next transfer point is shifted at each of the transfer points P1, P2, . . . , Pn. The shift direction at the transfer point includes an upward direction and a downward direction. For example, the transfer point P2is a point at which the line should be further shifted by one pixel in the upward direction up to the next transfer point P3. Accordingly, the transfer direction at the transfer point P2corresponds to the upward direction (↑). Similarly, at the transfer point P3, the transfer direction corresponds to the upward direction (↑) up to the next transfer point P4. The transfer direction at the transfer point P4corresponds to the downward direction (↓) different from the previously described direction.

The pseudo high-resolution processing unit204performs processing (pseudo high-resolution processing) to convert the halftone image data obtained after the phase transfer processing into data representing a high resolution in a pseudo manner by reducing the resolution. By this processing, the bitmap data with a resolution (e.g., 1,200 dpi) at the time of halftone processing is converted into bitmap data with a lower resolution (e.g., 600 dpi) both in the main-scanning direction and in the sub-scanning direction. The lower resolution is the resolution of the printer unit105.FIGS. 6A to 6Cschematically illustrates the pseudo high-resolution processing.FIG. 6Aillustrates a processing-target pixel (interest pixel601) and a processing rectangle602in binary bitmap data to which the pseudo high-resolution processing is applied. The pseudo high-resolution processing is performed by performing sampling while shifting the processing rectangle602and by performing a product sum operation using a multivalued filter within the area of the processing rectangle602. In this case, the processing rectangle602is an area formed of nine pixels including the interest pixel601and eight adjacent pixels. InFIG. 6A, shaded cells603each indicate the position (sampling position) of the interest pixel601for which sampling is performed. An arrangement interval (sampling interval) between the sampling positions603is determined by the reduction rate of the resolution in the main-scanning direction (lateral direction) and in the sub-scanning direction (longitudinal direction). In the present exemplary embodiment, the resolution conversion is performed from 1,200 dpi into 600 dpi both in the main-scanning direction and in the sub-scanning direction, and thus the sampling interval is 2 (=1,200/600) pixels, i.e., sampling is performed every two pixels.FIG. 6Bis an enlarged view of the processing rectangle602, andFIG. 6Cis a conceptual diagram of the multivalued filter corresponding to the processing rectangle602. The multivalued filter according to the present exemplary embodiment has nine product sum operation coefficients “a” corresponding to the respective pixels constituting the processing rectangle602.FIG. 6Dillustrates a specific example of the product sum operation coefficients “a” within the multivalued filter illustrated inFIG. 6C. Assuming that the coordinates of the interest pixel601are represented by (i, j) and the pixel value is represented by I (i, j), an output value OUT, which is the result of the product sum operation, is obtained by the following expression (1).

The above-described expression (1) means that the product of the pixel value I (i, j) of each pixel, which is represented by binary values within the processing rectangle602, and the product sum operation coefficient “a” corresponding to the coordinates is summed for the nine pixels and the sum is normalized into 16 values “0 to 15”. This makes it possible to convert the number of gradation levels from 2 into 16 while converting the resolution of the image data from 1,200 dpi into 600 dpi. By performing the pseudo high-resolution processing as described above, the effect of spot-multiplexing is obtained and it is possible to perform printing with a resolution higher than the actual resolution in a pseudo manner In this way, since it is possible to express an image whose resolution corresponds to 1,200 dpi by using 600 dpi bitmap data in the above-described example, even in the case where the capability of the printer unit105corresponds to a print resolution of 600 dpi, it is possible to print text or a line whose resolution corresponds to 1,200 dpi.

Next, a processing flow in the image processing unit108during print processing will be described.FIG. 7is a flowchart illustrating a processing flow in the image processing unit108. A series of processes in the processing is carried out by the CPU101reading a computer-executable program describing a procedure to be described below, loading from the ROM into the RAM in the memory102, and executing the loaded program.

In step701, in response to a print instruction, the CPU101acquires drawing bitmap data and attribute bitmap data generated by the RIP unit107. In step702, the color conversion processing unit201converts a color space (in this case, an RGB color space) of each pixel of the drawing bitmap into a color space (in this case, a CMYK color space) supported by the printer unit105by using a color conversion look-up table (LUT) or a matrix operation.

In step703, the halftone processing unit202selects a dithering matrix based on the attribute information about each pixel of the attribute bitmap. For example, in a case of the text attribute or line attribute, a high screen ruling dithering matrix is selected, and in a case of the graphics attribute or image attribute, a low screen ruling dithering matrix is selected. Further, the halftone processing unit202performs halftone processing on each pixel in the drawing bitmap by using the selected dithering matrix. In this way, the bitmap data (halftone image data) in which each multivalued pixel value of the drawing bitmap is converted into a binary value is generated. The dithering matrix used in the present exemplary embodiment will be described in detail below.

In step704, the phase transfer processing unit203corrects the curvature of the laser beam scan line by performing the above-described phase transfer processing on the binary bitmap data (e.g., 1,200 dpi) obtained after the halftone processing. In step705, the pseudo high-resolution processing unit204generates the multivalued bitmap data (e.g., 600 dpi) whose number of values is greater than two by performing the above-described pseudo high-resolution processing on the corrected binary bitmap data on which the phase transfer processing has been performed. The generated multivalued bitmap data is sent to the printer unit105and subjected to the print processing.

Next, the dithering matrix used in the present exemplary embodiment and advantageous effects of the dithering matrix will be described in detail with reference toFIGS. 8A and 8B,FIGS. 9A and 9B,FIGS. 10A, 10B, and 10C, andFIGS. 11A, 11B, and 11C.

FIGS. 8A and 8Beach illustrate an example of the dithering matrix according to the present exemplary embodiment. A dithering matrix800illustrated inFIG. 8Aincludes four cells (sub-matrices)801,802,803, and804, each of which forms a halftone dot. The sub-matrices801and802are adjacent to each other in the lateral direction, and the sub-matrices803and804are also adjacent to each other in the lateral direction. The number of thresholds in the sub-matrix801is the same as the number of thresholds in the sub-matrix802.FIGS. 9A and 9Beach illustrate an example of a growth order of cells that constitute the dithering matrix according to the present exemplary embodiment.FIG. 9Aillustrates a cell growth order900. Cells801to804illustrated inFIGS. 8A and 8Bare each configured to have the same growth order and different thresholds by integral-multiplying the cell growth order900by the total number of cells and then adding different values less than the total number of cells to each cell. For example, in the present exemplary embodiment, the cell growth order900has a value ranging from 0 to 35. The thresholds of the cells801to804are each obtained by multiplying the cell growth order900by 4, and adding 0 to the cell801, adding 1 to the cell802, adding 2 to the cell803, and adding 3 to the cell804. The threshold included in the cell801ranges from 0 to 140. The threshold included in the cell802ranges from 1 to 141. The threshold included in the cell803ranges from 2 to 142. The threshold included in the cell804ranges from 3 to 143. The value of each threshold is obtained by normalizing the value less than a maximum input pixel value according to the input pixel value of image data input to the halftone processing unit202. In the present exemplary embodiment, the maximum input pixel value of the image data input to the halftone processing unit202is 255, and thus the threshold is normalized to a value ranging from 0 to 254. Thus, the cells801to804include the maximum threshold143before normalization. Accordingly, after the normalization, the cell801includes a threshold ranging from 0 to 249, the cell802includes a threshold ranging from 2 to 250, the cell803includes a threshold ranging from 4 to 252, and the cell804includes a threshold ranging from 5 to 254. Cells arranged to have different thresholds and the same order of thresholds included in the respective cells as described above are each generally referred to as a sub-matrix. The cells801to804are arranged in such a manner that a halftone dot has a predetermined periodicity at a predetermined angle. This halftone dot cycle can be represented by two vectors. A first vector805has components of 6 in the main-scanning direction and −6 in the sub-scanning direction. A second vector806has components of 6 in the main-scanning direction and 6 in the sub-scanning direction. The length of each of the two vectors is obtained by the square-root of sum of squares of the components and is about 8.49. A cycle of a halftone dot is generally represented by screen ruling and is obtained by dividing a resolution by a length of a vector. The dithering matrix800represented by the two vectors forms halftone dots each having a screen ruling of 141 lpi and an angle of 45 degrees at a resolution of 1,200 dpi. In the cell growth order900, the same growth orders are set point-symmetrically to a growth center901that corresponds to the center of two pixels in the sub-scanning direction.

FIGS. 10A, 10B, and 10Ceach illustrate a halftone dot formed using the dithering matrix illustrated inFIG. 8A.FIG. 10Aillustrates binary bitmap data (1,200 dpi) obtained by performing halftone processing on the drawing bitmap in which all input pixel values are 84 by using the dithering matrix800, and then performing phase transfer processing. InFIG. 10A, location1001indicates a transfer point (see the transfer point P3illustrated inFIG. 4B) at which the line should be shifted by one pixel in the upward direction of the sub-scanning direction. It can be seen that the halftone dot within a second area is shifted by one pixel (one line) in the upward direction of the sub-scanning direction with the transfer point1001as a boundary. In a first area and the second area, halftone dots are connected and ON pixels are arranged in a line shape. The line on which the ON pixels are arranged is formed in the direction of the vector805. As the input pixel value increases, the area ratio is increased so as to increase the line in the direction of the vector806, thereby allowing the halftone dots to grow.FIG. 10Billustrates multivalued bitmap data (600 dpi) obtained after performing pseudo high-resolution processing on the binary bitmap data (1,200 dpi) obtained after the phase transfer processing as illustrated inFIG. 10A. In the first area illustrated inFIG. 10B, halftone dots are formed in such a manner that pixel values 10 are arranged on the left side of pixel values 14 as indicated by frames1003in the main-scanning direction and pixel values 4 are arranged on the right side of the pixel values 14. On the other hand, in the second area, halftone dots are formed in such a manner that pixel values 4 are arranged on the left side of pixel values 14 as indicated by frames1004in the main-scanning direction and pixel values 10 are arranged on the right side of the pixel values 14. It can be seen that halftone dots in the first area and the second area illustrated inFIG. 10Bare formed in a point symmetrical manner, while the total number of halftone dots in the first area is the same as that in the second area.FIG. 10Cschematically illustrates halftone dots formed by emitting a laser beam by the laser scanner using the multivalued bitmap data illustrated inFIG. 10B. The laser scanner sequentially emits exposure light (laser beam) corresponding to pixel values in the main-scanning direction. It is known that, for example, when the responsiveness of exposure light to pixel values has no linearity, the arrangement of pixel values in the main-scanning direction is greatly influenced. In the first area illustrated inFIG. 10C, halftone dots in which pixel values 9 are arranged on the left side of pixel values 13 as indicated by frames1005in the main-scanning direction and pixel values 0 are arranged on the right side of the pixel values 13, are formed by using the laser scanner. In the second area illustrated inFIG. 10C, halftone dots in which pixel values 2 are arranged on the left side of pixel values 13 as indicated by frames1006in the main-scanning direction and pixel values 8 are arranged on the right side of the pixel values 13, are formed by using the laser scanner. Thus, it can be seen that, in the case of using the dithering matrix800, halftone dots formed on a recording medium by using the laser scanner in the first area are different from those in the second area. In this case, in the above-described situation, on a recording medium, different halftone dots are formed in the first area and the second area, which are formed on both sides of the transfer point as a boundary, and the first and second areas are reproduced with different densities and colors.

A dithering matrix810illustrated inFIG. 8Bincludes four cells801,804,811, and812, each of which forms one halftone dot. The number of cells in the dithering matrix810is the same as the number of cells in the dithering matrix800. However, the thresholds included in the cells811and812are shifted by one pixel in the sub-scanning direction relative to the cells801and804. A cell growth order902indicates the growth order of the cells811and812. A growth center903of the cell growth order900is shifted upward by one pixel in the sub-scanning direction relatively to the growth center901of the cell growth order900. Since the arrangement of the cells801,804,811, and812is similar to that in the dithering matrix800, the dithering matrix810forms halftone dots each having a screen ruling of 141 lpi and an angle of 45 degrees at a resolution of 1,200 dpi.

FIG. 11Aillustrates binary bitmap data (1,200 dpi) obtained by performing halftone processing on the drawing bitmap in which all input pixel values are 84 by using the dithering matrix810, and then performing phase transfer processing. InFIG. 11A, location1101indicates a transfer point (see the transfer point P3illustrated inFIG. 5B) at which the line should be shifted by one pixel in the upward direction of the sub-scanning direction. It can be seen that the halftone dot within the second area is shifted by one pixel (one line) in the upward direction of the sub-scanning direction with the transfer point1101as a boundary. In the first area and the second area, halftone dots1102are connected and ON pixels are arranged in a line shape. As described above, the growth center of the cells811and812is shifted by one pixel relative to the cells801and804. Accordingly, it can be seen that the halftone dots fluctuate as compared withFIG. 10A.FIG. 11Billustrates multivalued bitmap data (600 dpi) obtained after performing pseudo high-resolution processing on the binary bitmap data (1,200 dpi) obtained after the halftone processing as illustrated inFIG. 11A. In the first area illustrated inFIG. 11B, halftone dots indicated by solid line frames1103and halftone dots indicated by broken line frames1104are formed. Also, in the second area, halftone dots indicated by the frames1103and halftone dots indicated by the frames1104are formed.FIG. 11Cschematically illustrates halftone dots formed by emitting a laser beam by the laser scanner using the multivalued bitmap data illustrated inFIG. 11B. In the first area illustrated inFIG. 11C, halftone dots indicated by solid line frames1105and halftone dots indicated by broken line frames1106are formed by using the laser scanner. In the present exemplary embodiment, the cells811and812whose the growth center is shifted by one pixel in the sub-scanning direction are arranged in the direction of the vector806. As a result, as illustrated inFIG. 11A, it can be seen that the line on which the ON pixels are arranged in the direction of the vector805fluctuates in the direction of the vector806as compared withFIG. 10A. Thus, it is possible to form the same halftone dots in the first area and the second area, which are formed on both sides of the transfer point as a boundary, regardless of the responsiveness of the laser scanner. The cells whose growth center is shifted by one pixel in the sub-scanning direction can also be arranged in the direction of the vector805, or in the direction of the sum of the vectors805and806. In a case where the cells whose growth center is shifted by one pixel in the sub-scanning direction are arranged in the direction of the vector805, it is possible to suppress fluctuations of halftone dots having a line shape. However, the intervals between halftone dots having a line shape in the direction of the vector806may be uneven, and thus considerable attention needs to be paid.

In the present exemplary embodiment, the description has been given of an example of the dithering matrix having a screen ruling of 141 lpi and an angle of 45 degrees at a resolution of 1,200 dpi, and including the first vector having components of 6 in the main-scanning direction and −6 in the sub-scanning direction, and the second vector having components of 6 in the main-scanning direction and 6 in the sub-scanning direction. However, the present disclosure is not limited to this example, as long as the vectors each include an even number of components in the main-scanning direction and the sub-scanning directions. The dithering matrix according to the present exemplary embodiment includes a combination of four cells. However, the configuration of the dithering matrix is not limited to this example. For example, eight or 16 cells may be combined and a half of the cells may be arranged so as to shift the growth center by one pixel in the sub-scanning direction with respect to the remaining half of the cells.

While in the present exemplary embodiment, a configuration has been described as an example in which the phase transfer processing is performed in the sub-scanning direction, the present disclosure is not limited to this configuration. For example, the phase transfer processing may be performed in the main-scanning direction. In this case, the direction in which the growth center of the halftone dots is shifted corresponds to the main-scanning direction that is the same as the direction in which the phase transfer processing is performed.

As described above, in the present exemplary embodiment, the dithering matrix is used in which the cell growth center is shifted by one pixel relatively in the sub-scanning direction in a plurality of cells constituting the dithering matrix forming halftone dots in a line shape. In this way, the same halftone dots can be formed in the first area and the second area, which are formed on both sides of the transfer point as a boundary, regardless of the responsiveness of the laser scanner, and thus the first and second areas can be reproduced with the same density and color.

In the first exemplary embodiment, a case has been described where the halftone processing unit202uses the dithering matrix that forms halftone dots in a line shape. In a second exemplary embodiment, a case is described where the halftone processing unit202uses a dithering matrix that forms halftone dots in a circular shape. The present exemplary embodiment differs from the first exemplary embodiment only in regard to the configuration of the dithering matrix used by the halftone processing unit202. Accordingly, portions similar to those in the first exemplary embodiment described above are denoted by the same reference numerals, and only different portions will be described below.

The dithering matrix used in the present exemplary embodiment and advantageous effects of the dithering matrix will be described in detail with reference toFIGS. 12A and 12B,FIGS. 13A and 13B,FIGS. 14A, 14B, and 14C, andFIGS. 15A, 15B, and15C.

FIGS. 12A and 12Beach illustrate an example of the dithering matrix according to the present exemplary embodiment. A dithering matrix1200illustrated inFIG. 12Aincludes four cells1201,1202,1203, and1204, each of which forms one halftone dot.

FIGS. 13A and 13Beach illustrate an example of a growth order of cells constituting the dithering matrix according to the present exemplary embodiment.FIG. 13Aillustrates a cell growth order1300. The cells1201to1204illustrated inFIG. 12Aare each configured to have the same growth order and different thresholds by integral-multiplying the cell growth order1300by the total number of cells and then adding different values less than the total number of cells to each cell. For example, in the present exemplary embodiment, the cell growth order1300has a value ranging from 0 to 39. The thresholds of the cells1201to1204are each obtained by multiplying the cell growth order1300by 4, and adding 0 to the cell1201, adding 1 to the cell1202, adding 2 to the cell1203, and adding 3 to the cell1204. The threshold included in the cell1201ranges from 0 to 156. The threshold included in the cell1202ranges from 1 to 157. The threshold included in the cell1203ranges from 2 to 158. The threshold included in the cell1204ranges from 3 to 159. The value of each threshold is obtained by normalizing a value less than a maximum input pixel value based on the input pixel value of image data input to the halftone processing unit202. In the present exemplary embodiment, the maximum input pixel value of the image data input to the halftone processing unit202is 255, and thus the threshold is normalized to a value ranging from 0 to 254. As a result, the cells1201to1204include the maximum threshold159before normalization. Accordingly, after the normalization, the cell1201includes a threshold ranging from 0 to 249, the cell1202includes a threshold ranging from 1 to 250, the cell1203includes a threshold ranging from 3 to 252, and the cell1204includes a threshold ranging from 4 to 254. A halftone dot cycle according to the present exemplary embodiment can be represented by two vectors. A first vector1205has components of 8 in the main-scanning direction and −4 in the sub-scanning direction. A second vector1206has components of 4 in the main-scanning direction and 8 in the sub-scanning direction. The length of each of the two vectors is about 8.49. The dithering matrix1200represented by the two vectors forms halftone dots each having a screen ruling of 134 lpi and an angle of 27 degrees at a resolution of 1,200 dpi. In the cell growth order1300, the same growth orders are set point-symmetrically to a growth center1301which corresponds to the center of two pixels in the sub-scanning direction.

FIGS. 14A, 14B, and 14Ceach illustrate an example of halftone dots formed using the dithering matrix illustrated inFIG. 12A.FIG. 14Aillustrates binary bitmap data (1,200 dpi) obtained by performing halftone processing on the drawing bitmap in which all input pixel values are 100 by using the dithering matrix1200, and then performing phase transfer processing. InFIG. 14A, a broken line1401indicates a transfer point (see the transfer point P3illustrated inFIG. 5B) at which the line should be shifted by one pixel in the upward direction of the sub-scanning direction. It can be seen that the halftone dot within the second area is shifted by one pixel (one line) in the upward direction of the sub-scanning direction with the transfer point1401as a boundary. In the first area and the second area, a plurality of halftone dots1402in which ON pixels are arranged in a circular shape is present. The halftone dots1402are formed in the direction of the vectors1205and1206. As the input pixel value increases, the area ratio is increased so as to increase the area of the shape in a circular shape with the growth center1301as a center, thereby allowing the halftone dots to grow.FIG. 14Billustrates multivalued bitmap data (600 dpi) obtained after performing pseudo high-resolution processing on the binary bitmap data (1,200 dpi) obtained after the phase transfer processing as illustrated inFIG. 14A. In the first area illustrated inFIG. 14B, halftone dots indicated by solid line frames1403are formed. In the second area illustrated inFIG. 14B, halftone dots indicated by broken line frames1404are formed. The halftone dots in the first area and the second area illustrated inFIG. 14Bare formed in a point symmetrical manner, while the total number of halftone dots in the first area is the same as that in the second area.FIG. 14Cschematically illustrates halftone dots formed by emitting a laser beam by the laser scanner using the multivalued bitmap data illustrated inFIG. 14B. In the first area illustrated inFIG. 14C, halftone dots indicated by solid line frames1405are formed by using the laser scanner. In the second area illustrated inFIG. 14C, halftone dots indicated by broken line frames1406are formed by using the laser scanner. As illustrated inFIG. 14C, it can be seen that, in a case of using the dithering matrix1200, the sum of halftone dots formed on a recording medium by using the laser scanner in the first area may be different from that in the second area. In this way, in the above-described situation, on a recording medium, different halftone dots are formed in the first area and the second area, which are formed on both sides of the transfer point as a boundary, and the first and second areas are reproduced with different densities and colors.

A dithering matrix1210illustrated inFIG. 12Bincludes four cells1201,1202,1211, and1212, each of which forms one halftone dot. The number of cells in the dithering matrix1210is the same as the number of cells in the dithering matrix1200. However, the thresholds included in the cells1211and1212are shifted by one pixel in the sub-scanning direction relative to the cells1201and1202. A cell growth order1302indicates the growth order of the cells1211and1212. It can be seen that a growth center1303of the cell growth order1302is shifted downward by one pixel in the sub-scanning direction with respect to the growth center1301of the cell growth order1300. Since the arrangement of the cells1201,1202,1211, and1212is similar to that in the dithering matrix1200, the dithering matrix1210forms halftone dots each having a screen ruling of 134 lpi and an angle of 27 degrees at a resolution of 1,200 dpi.

FIG. 15Aillustrates binary bitmap data (1,200 dpi) obtained by performing halftone processing on the drawing bitmap in which all input pixel values are 100 by using the dithering matrix1210, and then performing phase transfer processing. InFIG. 15A, a broken line1501indicates a transfer point (see the transfer point P3illustrated inFIG. 5B) at which the line should be shifted by one pixel in the upward direction of the sub-scanning direction. It can be seen that the halftone dot within the second area is shifted by one pixel (one line) in the upward direction of the sub-scanning direction with the transfer point1501as a boundary. In the first area and the second area, halftone dots1502in which ON pixels are arranged in a circular shape are present. However, as described above, the growth center of the cells1211and1212is shifted by one pixel relative to the cells1201and1202. Therefore, it can be seen that halftone dots fluctuate as compared withFIG. 14A.FIG. 15Billustrates multivalued bitmap data (600 dpi) obtained after performing pseudo high-resolution processing on the binary bitmap data (1,200 dpi) obtained after the phase transfer processing as illustrated inFIG. 15A. In the first area illustrated inFIG. 15B, halftone dots indicated by solid line frames1503and halftone dots indicated by broken line frames1504are formed. Also, in the second area, halftone dots indicated by the frames1503and halftone dots indicated by the frames1504are formed.FIG. 15Cschematically illustrates halftone dots formed by emitting a laser beam by the laser scanner using the multivalued bitmap data illustrated inFIG. 15B. In the first area illustrated inFIG. 15C, halftone dots indicated by solid line frames1505and halftone dots indicated by broken line frames1506are formed by using the laser scanner. In the present exemplary embodiment, the cells1211and1212whose the growth center is shifted by one pixel in the sub-scanning direction are arranged in the direction of the sum of the vectors1205and1206. As a result, as illustrated inFIG. 15A, the halftone dots located in the direction of the sum of the vectors1205and1206fluctuate in a staggered manner as compared withFIG. 14A. With this configuration, it is possible to form the same halftone dots in the first area and the second area, which are formed on both sides of the transfer point as a boundary, regardless of the responsiveness of the laser scanner.

The cells whose growth center is shifted by one pixel in the sub-scanning direction can also be arranged in the direction of the vector1205, or in the direction of the vector1206.

Also, in the present exemplary embodiment, the combination of the first vector and the second vector is not limited, as long as the vectors each include an even number of components in the main-scanning direction and the sub-scanning directions. While the dithering matrix according to the present exemplary embodiment includes a combination of four cells, the configuration of the dithering matrix is not limited to this example. For example, 8 or 16 cells may be combined and a half of the cells may be arranged so as to shift the growth center by one pixel in the sub-scanning direction with respect to the remaining half of the cells.

While in the present exemplary embodiment, the description has been given of a configuration in which the phase transfer processing is performed in the sub-scanning direction, the present disclosure is not limited to this configuration. For example, the phase transfer processing may be performed in the main-scanning direction. In this case, the direction in which the growth center of the halftone dots is shifted corresponds to the main-scanning direction that is the same as the direction in which the phase transfer processing is performed.

In the present exemplary embodiment, the dithering matrix used by the halftone processing unit202is a dithering matrix that forms halftone dots in a circular shape. However, there is no need to use the dithering matrix forming halftone dots in a circular shape for all attributes and all color screens. For example, a dithering matrix forming halftone dots in a circular shape may be used as the low screen ruling dithering matrix, and a dithering matrix forming halftone dots in a line shape may be used as the high screen ruling dithering matrix. Further, for example, the dithering matrix used for each color screen converted into CMYK color space may be changed and combined with other matrices by using, for example, cyan for the dithering matrix according to the second exemplary embodiment and magenta for the dithering matrix according to first exemplary embodiment.

As described above, in the present exemplary embodiment, the dithering matrix is used in which the cell growth center is shifted by one pixel relatively in the sub-scanning direction in a plurality of cells constituting the dithering matrix forming halftone dots in a circular shape. Consequently, the same halftone dots can be formed in the first area and the second area, which are formed on both sides of the transfer point as a boundary, regardless of the responsiveness of the laser scanner, and thus the first and second areas can be reproduced with the same density and color.

In the first and second exemplary embodiments, a case is described where the halftone processing unit202uses the dithering matrix in which the components of the first and second vectors are a combination of even numbers. In a third exemplary embodiment, a case is described where a dithering matrix in which the components of the first and second vectors are a combination of odd numbers is used. The third exemplary embodiment differs from the first and second exemplary embodiments only in regard to the configuration of the dithering matrix used by the halftone processing unit202. Accordingly, portions similar to those in the first and second exemplary embodiment described above are denoted by the same reference numerals, and only different portions will be described below.

The dithering matrix used in the present exemplary embodiment and advantageous effects of the dithering matrix will be described in detail with reference toFIGS. 16A and 16B,FIGS. 17A and 17B,FIGS. 18A, 18B, and 18C, andFIGS. 19A, 19B, and19C.

FIGS. 16A and 16Beach illustrate an example of the dithering matrix according to the present exemplary embodiment. A dithering matrix1600illustrated inFIG. 16Aincludes four cells1601,1602,1603, and1604, each of which forms one halftone dot.

FIGS. 17A and 17Beach illustrate an example of a growth order of cells constituting the dithering matrix according to the present exemplary embodiment.FIG. 17Aillustrates a cell growth order1700. The cells1601to1604illustrated inFIG. 16Aare each configured to have the same growth order and different thresholds by integral-multiplying the cell growth order1700by the total number of cells and then adding different values less than the total number of cells to each cell. For example, in the present exemplary embodiment, the cell growth order1700has a value ranging from 0 to 24. The thresholds of the cells1601to1604are each obtained by multiplying the cell growth order1700by 4, and adding 0 to the cell1601, adding 1 to the cell1602, adding 2 to the cell1603, and adding 3 to the cell1604. The threshold included in the cell1601ranges from 0 to 96. The threshold included in the cell1602ranges from 1 to 97. The threshold included in the cell1603ranges from 2 to 98. The threshold included in the cell1604ranges from 3 to 99. The value of each threshold is obtained by normalizing a value less than a maximum input pixel value based on the input pixel value of image data input to the halftone processing unit202is used. In the present exemplary embodiment, the maximum input pixel value of the image data input to the halftone processing unit202is 255, and thus the threshold is normalized to a value ranging from 0 to 254. Thus, the cells1601to1604include the maximum threshold99before normalization. Accordingly, after the normalization, the cell1601includes a threshold ranging from 0 to 246, the cell1602includes a threshold ranging from 3 to 249, the cell1603includes a threshold ranging from 5 to 251, and the cell1604includes a threshold ranging from 8 to 254. A halftone dot cycle according to the present exemplary embodiment can be represented by two vectors. A first vector1605has components of 5 in the main-scanning direction and −5 in the sub-scanning direction. A second vector1606has components of 5 in the main-scanning direction and 5 in the sub-scanning direction. The length of each of the two vectors is about 7.07. The dithering matrix1600represented by the two vectors forms halftone dots each having a screen ruling of 170 lpi and an angle of 45 degrees at a resolution of 1,200 dpi. In the cell growth order1700, the same growth orders are set point symmetrically to a growth center1701which corresponds to the center of two pixels in the sub-scanning direction.

FIGS. 18A, 18B, and 18Ceach illustrate an example of halftone dots formed using the dithering matrix illustrated inFIG. 16A.FIG. 18Aillustrates binary bitmap data (1,200 dpi) obtained by performing halftone processing on the drawing bitmap in which all input pixel values are 70 by using the dithering matrix1600, and then performing phase transfer processing. InFIG. 18A, a broken line1801indicates a transfer point (see the transfer point P3illustrated inFIG. 5B) at which the line should be shifted by one pixel in the upward direction of the sub-scanning direction. It can be seen that the halftone dot within the second area is shifted by one pixel (one line) in the upward direction of the sub-scanning direction with the transfer point1801as a boundary. In the first area and the second area, a plurality of halftone dots1802in which ON pixels are arranged in a circular shape is present. The halftone dots1802are formed in the direction of the vectors1605and1606. As the input pixel value increases, the area ratio is increased so as to increase the area of the shape in a circular shape with the growth center1701as a center, thereby allowing the halftone dots to grow.FIG. 18Billustrates multivalued bitmap data (600 dpi) obtained after performing pseudo high-resolution processing on the binary bitmap data (1,200 dpi) obtained after the phase transfer processing as illustrated inFIG. 18A. In the first area illustrated inFIG. 18B, halftone dots indicated by solid line frames1803and halftone dots indicated by dashed-dotted line frames1804are formed. In the second area illustrated inFIG. 18B, halftone dots indicated by broken line frames1805and halftone dots indicated by dashed-two dotted line frames1806are formed. The halftone dots in the first area and the second area illustrated inFIG. 18Bare formed in a point symmetrical manner, while the total number of halftone dots in the first area is the same as that in the second area.FIG. 18Cschematically illustrates halftone dots formed by emitting a laser beam by the laser scanner using the bitmap data illustrated inFIG. 18B. In the first area illustrated inFIG. 18C, halftone dots indicated by solid line frames1807and halftone dots indicated by dashed-dotted line frames1808are formed by using the laser scanner. In the second area illustrated inFIG. 18C, halftone dots indicated by broken line frames1809and halftone dots indicated by dashed-two dotted line frames1810are formed by using the laser scanner. As illustrated inFIG. 18C, in a case of using the dithering matrix1600, halftone dots formed on a recording medium through the laser scanner in the first area may be different from those in the second area. In other words, in the above-described situation, on a recording medium, different halftone dots are formed in the first area and the second area, which are formed on both sides of the transfer point as a boundary, and the first and second areas are reproduced with different densities and colors.

A dithering matrix1610illustrated inFIG. 16Bincludes four cells1601,1603,1611, and1612, each of which forms one halftone dot. The number of cells in the dithering matrix1610is the same as the number of cells in the dithering matrix1600. However, the thresholds included in the cells1611and1612are shifted by one pixel in the main-scanning direction relative to the cells1601and1603. A cell growth order1702indicates the growth order of the cells1611and1612. It can be seen that a growth center1703of the cell growth order1702is shifted rightward by one pixel in the main-scanning direction with respect to the growth center1701of the cell growth order1700. Since the arrangement of the cells1601,1603,1611, and1612is similar to that in the dithering matrix1600, the dithering matrix1610forms halftone dots each having a screen ruling of 170 lpi and an angle of 45 degrees at a resolution of 1,200 dpi.

FIG. 19Aillustrates binary bitmap data (1,200 dpi) obtained by performing halftone processing on the drawing bitmap in which all input pixel values are 70 by using the dithering matrix1610, and then performing phase transfer processing. InFIG. 19A, a broken line1901indicates a transfer point (see the transfer point P3illustrated inFIG. 5B) at which the line should be shifted by one pixel in the upward direction of the sub-scanning direction. It can be seen that the halftone dot within the second area is shifted by one pixel (one line) in the upward direction of the sub-scanning direction with the transfer point1901as a boundary. In the first area and the second area, a plurality of halftone dots1902in which ON pixels are arranged in a circular shape is present. However, as described above, the growth center of the cells1611and1612is shifted by one pixel relative to the cells1601and1603. Accordingly, it can be seen that halftone dots fluctuate as compared withFIG. 18A.FIG. 19Billustrates multivalued bitmap data (600 dpi) obtained after performing pseudo high-resolution processing on the binary bitmap data (1,200 dpi) obtained after the phase transfer processing as illustrated inFIG. 19A. In the first area illustrated inFIG. 19B, halftone dots indicated by solid line frames1903, halftone dots indicated by dashed-dotted line frames1904, halftone dots indicated by broken line frames1905, and halftone dots indicated by dashed-two dotted line frames1906are formed. Also, in the second area, halftone dots indicated by the frames1903, halftone dots indicated by the frames1904, halftone dots indicated by the frames1905, and halftone dots indicated by the frames1906are formed.FIG. 19Cschematically illustrates halftone dots formed by emitting a laser beam by the laser scanner using the multivalued bitmap data illustrated inFIG. 19B. In the first area illustrated inFIG. 19C, halftone dots indicated by solid line frames1907, halftone dots indicated by dashed-dotted line frames1908, halftone dots indicated by broken line frames1909, and halftone dots indicated by dashed-two dotted line frames1910are formed by using the laser scanner. In the present exemplary embodiment, the cells1611and1612whose the growth center is shifted by one pixel in the main-scanning direction are arranged in the direction of the vector1606. As a result, as illustrated inFIG. 19A, it can be seen that halftone dots located in the direction of the vector1606are shifted as compared withFIG. 18A. Consequently, it is possible to form the same halftone dots in the first area and the second area, which are formed on both sides of the transfer point as a boundary, regardless of the responsiveness of the laser scanner.

The cells whose growth center is shifted by one pixel in the main-scanning direction can also be arranged in the direction of the vector1605, or in the direction of the sum of the vectors1605and1606.

Also, in the present exemplary embodiment, the combination of the first vector and the second vector is not limited, as long as the vectors each include an odd number of components in the main-scanning direction and the sub-scanning directions. The dithering matrix according to the present exemplary embodiment includes a combination of four cells. However, the configuration of the dithering matrix is not limited to this example. For example, 8 or 16 cells may be combined and a half of the cells may be arranged so as to shift the growth center by one pixel in the main-scanning direction with respect to the remaining half of the cells.

While in the present exemplary embodiment, a configuration has been described in which the phase transfer processing is performed in the sub-scanning direction, the present disclosure is not limited to this configuration. For example, the phase transfer processing may be performed in the main-scanning direction. In this case, the direction in which the growth center of halftone dots is shifted corresponds to the sub-scanning direction perpendicular to the direction in which the phase transfer processing is performed.

In the third exemplary embodiment, a configuration has been described in which the components of the first and second vectors in the main-scanning direction and the sub-scanning direction are a combination of odd numbers in the dithering matrix used by the halftone processing unit202. However, the dithering matrix need not necessarily be used for all color screens. The dithering matrix used for each color screen converted into a CMYK color space may be changed. For example, the dithering matrix to be adopted may be appropriately changed for each color by using, for example, cyan for the dithering matrix according to the third exemplary embodiment and magenta for the dithering matrix according to the first or second exemplary embodiment. Alternatively, different dithering matrices may be used as the high screen ruling dithering matrix and the low screen ruling dithering matrix, respectively.

As described above, in the present exemplary embodiment, the dithering matrix has been used in which the cell growth center is shifted by one pixel relatively in the main-scanning direction in a plurality of cells constituting the dithering matrix in which the components of the first and second vectors are a combination of odd numbers. Consequently, the same halftone dots can be formed in the first area and the second area, which are formed on both sides of the transfer point as a boundary, regardless of the responsiveness of the laser scanner, and thus the first and second areas can be reproduced with the same density and color.

The units described throughout the present disclosure are exemplary and/or preferable modules for implementing processes described in the present disclosure. The term “unit”, as used herein, may generally refer to firmware, software, hardware, or other component, such as circuitry or the like, or any combination thereof, that is used to effectuate a purpose. The modules can be hardware units (such as circuitry, firmware, a field programmable gate array, a digital signal processor, an application specific integrated circuit or the like) and/or software modules (such as a computer readable program or the like). The modules for implementing the various steps are not described exhaustively above. However, where there is a step of performing a certain process, there may be a corresponding functional module or unit (implemented by hardware and/or software) for implementing the same process. Technical solutions by all combinations of steps described and units corresponding to these steps are included in the present disclosure.

Other Embodiments

Embodiments of the present disclosure can also be realized by a computerized configuration(s) of a system or apparatus that reads out and executes computer executable instructions recorded on a storage medium (e.g., non-transitory computer-readable storage medium) to perform the functions of one or more of the above-described embodiment(s) of the present disclosure, and by a method performed by the computerized configuration(s) of the system or apparatus by, for example, reading out and executing the computer executable instructions from the storage medium to perform the functions of one or more of the above-described embodiment(s). The computerized configuration(s) may comprise one or more of a processor, memory, central processing unit (CPU), micro processing unit (MPU), circuitry, or combinations thereof, and may include a network of separate computers or separate computer processors. The computer executable instructions may be provided to the computerized configuration(s), for example, from a network or the storage medium. The storage medium may include, for example, one or more of a hard disk, a random-access memory (RAM), a read only memory (ROM), a storage of distributed computing systems, an optical disk (such as a compact disc (CD), digital versatile disc (DVD), or Blu-ray Disc (BD)™), a flash memory device, a memory card, and the like.

This application claims the benefit of priority from Japanese Patent Applications No. 2017-243007, filed Dec. 19, 2017, and No. 2018-086501, filed Apr. 27, 2018, which are each hereby incorporated by reference herein in their entirety.