IMAGE PROCESSING APPARATUS AND IMAGE PROCESSING METHOD
20170289399 · 2017-10-05
Assignee
Inventors
Cpc classification
H04N1/4058
ELECTRICITY
H04N2201/0094
ELECTRICITY
H04N1/4057
ELECTRICITY
International classification
Abstract
An image processing apparatus capable of improving image quality of binarized image data is provided. The image processing apparatus includes a generation part that generates a binarized image data. The binarized image data comprises a first cell, containing a first dot pattern in which an outside pixel density is higher than an inside pixel density; and a second cell, containing a second dot pattern in which an inside pixel density is higher than an outside pixel density.
Claims
1. An image processing apparatus, comprising: a generation part, generating a binarized image data, wherein the binarized image data comprises a first cell, containing a first dot pattern in which an outside pixel density is higher than an inside pixel density; and a second cell, containing a second dot pattern in which an inside pixel density is higher than an outside pixel density.
2. The image processing apparatus according to claim 1, wherein in the binarized image data, the first dot pattern and the second dot pattern are alternately arranged.
3. The image processing apparatus according to claim 1, wherein in the binarized image data, the first dot pattern and the second dot pattern are arranged adjacent to each other in a row direction and a column direction.
4. The image processing apparatus according to claim 1, wherein the binarized image data contains the first dot patterns or the second dot patterns, and the first or the second dot patterns are arranged at substantially 45°.
5. The image processing apparatus according to claim 1, wherein the binarized image data contains the first dot patterns, and the first dot patterns are arranged in point symmetry.
6. The image processing apparatus according to claim 1, wherein the binarized image data contains the second dot patterns, and the second dot patterns are arranged in point symmetry.
7. The image processing apparatus according to claim 1, wherein the first dot pattern formed in the first cell has a substantially circular shape.
8. The image processing apparatus according to claim 1, wherein a region other than the second dot pattern formed in the second cell is a substantially circular shape.
9. An image processing apparatus, comprising an acquisition part, acquiring a multitone original image data; and a generation part, dividing the multitone original image data into a plurality of regions, to generate a binarized image data based on a plurality of dither matrices of multiple types having different threshold value arrangements in each of the regions.
10. The image processing apparatus according to claim 9, wherein based on the plurality of the dither matrices, the generation part generates the binarized image data in which a plurality of dot patterns of multiple types are formed, wherein when tone values of all pixels contained in the region change respectively from a highlight side to a shadow side, each of the plurality of the dot patterns grows in different manners from each other.
11. The image processing apparatus according to claim 10, wherein the binarized image data has a plurality of cells respectively corresponding to the plurality of the regions, and the plurality of the dither matrices comprises: a first dither matrix, forming a first dot pattern that grows from an inside toward an outside of the cell when the tone value of each of all the pixels contained in the region changes from the highlight side to the shadow side; and a second dither matrix, forming a second dot pattern that grows from the outside toward the inside of the cell when the tone value of each of all the pixels contained in the region changes from the highlight side to the shadow side.
12. The image processing apparatus according to claim 11, wherein the plurality of the cells are arranged in a matrix, and the first dot patterns and the second dot patterns are alternately arranged side by side in a row direction and a column direction of the plurality of cells.
13. An image processing method for generating a binarized image data, comprising: acquiring a multitone original image data; and dividing the multitone original image data into a plurality of regions, and carrying out a halftone process in each of the regions using any of a plurality dither matrices of multiple types having different threshold value arrangements, to generate the binarized image data.
14. The image processing method according to claim 13, wherein the binarized image data comprises a first cell, containing a first dot pattern in which an outside pixel density is higher than an inside pixel density; and a second cell, containing a second dot pattern in which an inside pixel density is higher than an outside pixel density.
15. The image processing method according to claim 14, comprising: alternately arranging the first dot pattern and the second dot pattern in the binarized image data.
16. The image processing method according to claim 14, comprising: in the binarized image data, arranging the first dot pattern and the second dot pattern adjacent to each other in a row direction and a column direction.
17. The image processing method according to claim 14, wherein the binarized image data contains the first dot patterns or the second dot patterns, and arranging the first or the second dot patterns at substantially 45°.
18. The image processing method according to claim 14, wherein the binarized image data contains the first dot patterns or the second patterns, and arranging the first or the second dot patterns in point symmetry.
19. The image processing method according to claim 14, wherein the first dot pattern formed in the first cell has a substantially circular shape, and a region other than the second dot pattern formed in the second cell is a substantially circular shape.
20. The image processing method according to claim 14, wherein based on the plurality of the dither matrices, generating the binarized image data in which the first and the second dot patterns are different types, wherein when tone values of all pixels contained in the region change respectively from a highlight side to a shadow side, each of the plurality of the dot patterns grows in different manners from each other.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
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DESCRIPTION OF THE EMBODIMENTS
[0039] Hereinafter, embodiments of the disclosure are explained in detail using the drawings. Moreover, all of the embodiments explained hereinafter show general or specific examples. The numerical values, shapes, materials, components, arrangement positions and connection forms of the components, steps and order of the steps shown in the following embodiments are examples and do not intend to limit the invention. In addition, among the components in the following embodiments, the components not recited in the independent claims are explained as arbitrary components.
Embodiments
1-1. Functional Configuration of Printing Apparatus
[0040] First of all, a functional configuration of a printing apparatus 2 according to an embodiment is explained with reference to
[0041] The printing apparatus 2 (an example of an image processing apparatus) according to an embodiment is, for example, a laser printer for printing binarized image data 4 onto a paper 6. As shown in
[0042] The acquisition part 8 acquires original image data 16 transmitted from, for example, the external terminal apparatus. The original image data 16 is, for example, multitone gray scale image data having an 8-bit tone value (“0” to “255”). As shown in
[0043] The generation part 10 divides the original image data 16 into a plurality of regions 19 (19a, 19b, 19c and 19d), and carries out a halftone process in each of the regions 19. Moreover, each of the plurality of regions 19 contains, for example, a total of 64 pixels 18 in an 8×8 pixel array. The generation part 10 carries out the halftone process, and as a result, the binarized image data 4 is generated in which a large number of halftone dots (first halftone dots 20 and second halftone dots 22) are formed and the halftone dots contain one or a plurality of pixels to form a dot. The halftone process is, for example, an amplitude modulated (AM) halftone process by dithering using either the first dither matrix 24 or the second dither matrix 26 (described later) stored in the memory part 12.
[0044] Furthermore, in the binarized image data 4, a plurality of cells 30 are two-dimensionally arranged, in which the cells 30 are unit regions having either the first halftone dot 20 (an example of a first dot pattern) or the second halftone dot 22 (an example of a second dot pattern) formed therein.
[0045] As shown in
[0046] Herein, the pixel 28 having the pixel value of “255” is a white pixel in which no dot is formed; the pixel 28 having the pixel value of “0” is a black pixel in which a dot is formed.
[0047] The opposite situation is also possible in the case of a negative/positive inverted image which has undergone a process of reversing white and black of the image. However, even in binarizing the negative/positive inverted image, only the left and right cells 30 are interchanged, and an image substantially the same as that of the present embodiment can be generated. Therefore, in the present embodiment, the case of the negative/positive inverted image does not need to be considered.
[0048] The plurality of cells 30 respectively correspond to the plurality of regions 19 in the original image data 16. That is, in the example shown in
[0049] The memory part 12 is a memory for storing the first dither matrix 24 and the second dither matrix 26. As shown in
[0050] The printing part 14 prints, on to the paper 6, the binarized image data 4 generated by the generation part 10. Moreover, the printing part 14 forms a large number of first halftone dots 20 and second halftone dots 22 on the paper 6 by fixing a black toner to the paper 6. Since the large number of first halftone dots 20 and second halftone dots 22 are formed on the paper 6 in this way, the binarized image data 4 is printed onto the paper 6.
1-2. Method for Forming First Halftone Dot and Second Halftone Dot
[0051] Herein, the method for forming the first halftone dot 20 and the second halftone dot 22 by the generation part 10 is explained with reference to
[0052] When the generation part 10 carries out the halftone process on the original image data 16, the first dither matrix 24 and the second dither matrix 26 are alternately used in a row direction (the transverse direction in
[0053] Specifically, each pixel value of 64 pixels 18 in the 8×8 pixel array contained in the upper left region 19a in the original image data 16 shown in
[0054] Similarly, when carrying out the halftone process on the original image data 16, the generation part 10 compares each pixel value of 64 pixels 18 in the 8×8 pixel array contained in the upper right region 19b in the original image data 16 shown in
[0055] Similarly, when carrying out the halftone process on the original image data 16, the generation part 10 compares each pixel value of 64 pixels 18 in the 8×8 pixel array contained in the lower left region 19c in the original image data 16 shown in
[0056] Similarly, when carrying out the halftone process on the original image data 16, the generation part 10 compares each pixel value of 64 pixels 18 in the 8×8 pixel array contained in the lower right region 19d in the original image data 16 shown in
[0057] As shown in
1-3. First Dither Matrix and Second Dither Matrix
[0058] Next, the first dither matrix 24 and the second dither matrix 26 are explained with reference to
[0059] As shown in
[0060] Specifically, as shown in
[0061] On the other hand, as shown in
1-4. Flow of Process Performed by Printing Apparatus
[0062] Next, a flow of a process (image processing method) performed by the printing apparatus 2 according to an embodiment is explained with reference to
[0063] As shown in
[0064] Back to step S4, if the printing mode is not the predetermined printing mode (NO in S4), a general dither matrix is selected (S8). Moreover, the “general dither matrix” refers to a type of dither matrix arranged in a direction inclined 0° with respect to the row direction and the column direction. Then, steps S6 and S7 are carried out similarly to the above.
[0065] Herein, specific examples of the binarized image data 4 generated by the halftone process according to an embodiment are shown.
[0066] Moreover, a size of the binarized image data 4 shown in each of
[0067] In the binarized image data 4 shown in each of
[0068] As clear from
1-5. Effect
[0069] Next, effects obtained by the printing apparatus 2 according to an embodiment are explained. The inventors discovered that, as a distance between halftone dots in the binarized image data 4 increases, a feeling of roughness that occurs in the binarized image data 4 becomes stronger. As in the conventional halftone process explained in the part “Description of the Related Art,” if each of the large number of halftone dots grows from inside toward outside of the cell 30 in a constant step cycle, since the distance between the halftone dots in the binarized image data 4 becomes relatively larger, the feeling of roughness that occurs in the binarized image data 4 may become stronger.
[0070] With respect to this, as described above, by the printing apparatus 2 according to an embodiment, the first halftone dot 20 and the second halftone dot 22 that grow in different manners from each other are formed in the binarized image data 4. Accordingly, as shown in
[0071] Furthermore, as shown in
Variants
[0072] The above has explained the image processing apparatus according to the embodiments of the invention. However, the invention is not limited to these embodiments. For example, the above embodiments may be properly combined with each other.
[0073] For example, in the above embodiments, the printing apparatus 2 is configured as a laser printer. However, the printing apparatus 2 is not limited thereto, but may be configured as, for example, an inkjet printer or a multifunction peripheral (MFP) or the like. In the case where the printing apparatus 2 is configured as a multifunction peripheral, the acquisition part 8 will acquire the original image data 16 read by a scanner. In addition, in the case where the printing apparatus 2 is configured as a multifunction peripheral, the printing part 14, while reciprocally moving a recording head (not illustrated) in a direction substantially perpendicular to a conveyance direction of the paper 6, discharges black ink from the recording head to the paper 6 at proper timings, so as to form a large number of halftone dots on the paper 6.
[0074] For example, in the above embodiments, two types of halftone dots are formed in the binarized image data 4. However, the invention is not limited thereto, and three or more types of halftone dots, for example, may be formed.
[0075] For example, in the above embodiments, an adjacent pair of first halftone dots 20 are arranged side by side in the direction inclined 45° with respect to the row direction and the column direction respectively of the plurality of cells 30. However, the invention is not limited thereto, and the first halftone dots 20 may be arranged side by side in a direction inclined at an arbitrary angle (e.g., 30°). With regard to the second halftone dot 22, similarly, the second halftone dots 22 may be arranged side by side in a direction inclined at an arbitrary angle (e.g., 30°) with respect to the row direction and the column direction respectively of the plurality of cells 30.
[0076] In addition, a noise component may be intentionally added to each threshold value of the first dither matrix 24 and the second dither matrix 26 explained in the above embodiments. Accordingly, due to counterbalance between the noise component and a noise component caused by hardware, the image quality of the binarized image data 4 can be further improved.
Other Variants
[0077] In addition, the above image processing apparatus may be configured as, specifically, a computer system including a microprocessor, a read-only memory (ROM), a random access memory (RAM), a hard disk drive, a display unit, a keyboard, a mouse and so on. The RAM or the hard disk drive stores a computer program therein. The microprocessor operates in accordance with the computer program, and thereby the image processing apparatus achieves its functions. Herein, the computer program is configured by combining a plurality of opcodes showing instructions to a computer in order to achieve a predetermined function.
[0078] Furthermore, a part of or all of the components that compose the above image processing apparatus may include a system large-scale integration (LSI). The system LSI is a supermultifunctional LSI manufactured by integrating a plurality of components on a chip, and includes, for example, a computer system including a microprocessor, a ROM, a RAM and so on. In this case, the computer program is stored in the ROM. The microprocessor operates in accordance with the computer program, and thereby the system LSI achieves its functions.
[0079] In addition, a field-programmable gate array (FPGA) that can be programmed after manufacture of the LSI, may be utilized for the integrated circuit.
[0080] Furthermore, a part of or all of the components that compose the above image processing apparatus may include an IC card or a single module detachable from the image processing apparatus. The IC card or the module is a computer system including a microprocessor, a ROM, a RAM and so on. The IC card or the module may include the above supermultifunctional LSI. The microprocessor operates in accordance with the computer program, and thereby the IC card or the module achieves its functions. The IC card or the odule may have tamper resistance.
[0081] In addition, the invention may be the method shown above. In addition, the invention may be a computer program carrying out the method by a computer, or may be a digital signal including the above computer program.
[0082] Furthermore, the invention may record the above computer program or the above digital signal in a computer readable non-transitory recording medium such as, for example, a flexible disk, a hard disk, a CD-ROM, a magneto-optical drive (MO), a digital versatile disc (DVD), a DVD-ROM, a DVD-RAM, a Blu-ray® Disc (BD), a semiconductor memory or the like. In addition, the invention may be the above digital signal recorded in these non-transitory recording media.
[0083] In addition, the invention may transmit the above computer program or the above digital signal via a telecommunication line, a wireless or wired communication line, a network represented by the Internet, data broadcasting or the like.
[0084] In addition, the invention may be a computer system including a microprocessor and a memory, wherein the memory stores the above computer program, and the microprocessor operates in accordance with the above computer program.
[0085] In addition, the above computer program or the above digital signal may be recorded in the above non-transitory recording media to be transferred, or may be transferred via the above network or the like, so as to be carried out by another independent computer system.
[0086] The image processing apparatus of the invention may be applied as, for example, an inkjet printer or a laser printer.