CN101489023A - Green noise error diffusion method based on tone dependency and related printing apparatus - Google Patents
Green noise error diffusion method based on tone dependency and related printing apparatus Download PDFInfo
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- CN101489023A CN101489023A CNA200910037014XA CN200910037014A CN101489023A CN 101489023 A CN101489023 A CN 101489023A CN A200910037014X A CNA200910037014X A CN A200910037014XA CN 200910037014 A CN200910037014 A CN 200910037014A CN 101489023 A CN101489023 A CN 101489023A
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Abstract
The invention relates to a green noise error diffusion method of tone dependence, comprising: setting first and second thresholds, and determining two-value numerical value of the color gradation value of input image according to the first and second thresholds; subtracting the color gradation by the two-value numerical value to generate error value; executing error diffusion on the error value to generate error diffusion accumulated value; regulating the color gradation value based on the error diffusion accumulated value; executing magnetic hysteresis filtration on the two-value numerical value to generate output dependence feedback value; and regulating the color gradation value based on the output dependence feedback value.
Description
Technical field
Relevant a kind of halftoning (half-tone) image processing technique of the present invention refers to a kind of green noise error diffusion method based on tone dependency and related printing apparatus thereof that promotes print quality especially.
Background technology
Technology is applied on the printing device widely in the halftoning image place, the halftoning image processing technique is the halftoning image of two-value with the continuous tone video conversion, whether printing device is printed according to the pixel decision of this two-value image, to produce the print result near the continuous tone image.Frequency modulation (Frequency Modulation) halftoning image treatment method often uses on ink-jet printer, and as error diffusion method, but the method is easy to generate the phenomenon of hue shift at laser printer.Amplitude modulation (Amplitude Modulation) halftoning image treatment method often uses at laser printer, but the method is easy to generate Moore line (Moire) when duplicating (Copy).
The characteristic of green noise (Green-Noise) error diffusion method can solve the phenomenon of laser printer hue shift between Frequency And Amplitude Modulation halftoning image treatment method, also can reduce the Moore line that produces when duplicating.Please refer to Fig. 1 and Fig. 2, Fig. 1 and Fig. 2 are the schematic diagram of the function mode of the traditional green noise error method of diffusion of explanation.Wherein, Fig. 1 represents that Fig. 2 then represents through the pixel color range value after the diffusion of error diffusion device through the revised pixel color range of output feedback device value.Shown in Figure 1A, (its color range value is 155, (x-1 for x, y) the present pixel of handling of expression, y-1), (x, y-1), (x+1, y-1), (x-1 y) is the pixel handled, (x+1, y), (x-1, y+1), (x, y+1), (x+1 y+1) is untreated pixel.Figure 1B then represents to export the distribution schematic diagram of feedback weighted value,
*(x, y), numerical value 0.8 is that (x, second output feedback weighted value y), numerical value 1.2 are pixel (x, first output feedback weighted value y) to pixel to the pixel that expression is handled at present.Fig. 1 C then represent Figure 1A pixel (x, neighborhood pixels y) (x-1, y) and (x is y-1) according to the resulting output backoff values of output feedback weighted value of Figure 1B.Fig. 1 D represents that then (x y) adds resulting correction color range value after the output backoff values of Fig. 1 C to Figure 1A pixel.
Please then refer to Fig. 2, because Fig. 1 D pixel (x, correction color range value 359 y) is greater than threshold value 127, and therefore (x, two-value numerical value y) is made as 255, shown in Fig. 2 A with pixel.Fig. 2 B then represents the distribution schematic diagram of an error diffusion weighted value,
*The pixel that expression is handled at present (x, y), two numerical value 0.5 difference represent pixel (x, first error diffusion weighted value y) and second error diffusion weighted values.(x, (x, the error amount of two-value numerical value 255 y) equals (100) to pixel among Figure 1A for color range value 155 y) and the pixel among Fig. 2 A.Fig. 2 C represents that then error amount (100) is according to the resulting error diffusion value of the error diffusion weighted value of Fig. 2 B.At last, with the error diffusion value of Fig. 2 C diffuse to Fig. 2 A pixel (x, neighborhood pixels y) (x+1, y) and (x, y+1), the pixel color range value after can obtaining spreading is shown in Fig. 2 D.Repeat the flow process of Fig. 1 and Fig. 2, finish up to all processes pixel.
Green noise error method of diffusion is in bright color range, and middle color range and dark rank are the image fault of regular lines still, so this known techniques still has the space of improvement.
Summary of the invention
Technical problem to be solved by this invention provides a kind of green noise error diffusion method based on tone dependency and related printing apparatus thereof, to solve the problem in the prior art.
The invention provides a kind of green noise error diffusion method based on tone dependency, in order to handle continuous tone input image, this continuous tone input image system is arranged in a two-dimensional array, and with (x, y) represent this continuous tone to import the position of one of image specific pixel, this specific pixel can comprise a plurality of colors, and this method includes following steps: the color stage value according to one of this specific pixel first color produces one of this first color first output feedback weighted value and one second output feedback weighted value; Carry out an output feedback operation according to this first output feedback weighted value of this first color of this specific pixel and this second output feedback weighted value and revise the color range value to produce one of this first color; According to this color range value of this first color of this specific pixel to produce one of this first color first threshold value and one second threshold value; Decide one of this first color output two-value numerical value according to this correction color range value of this first color of this specific pixel and this first threshold value and this second threshold value; According to this color range value of this first color of this specific pixel to produce one of this color value first error diffusion weighted value and one second error diffusion weighted value; And according to this first color of this specific pixel should output two-value numerical value and this first error diffusion weighted value and this second error diffusion weighted value, carry out an error diffusion operation.
The invention provides a kind of printing equipment that is used for handling continuous tone input image, this continuous tone input image system is arranged in a two-dimensional array, and with (x, y) represent this continuous tone to import the position of one of image specific pixel, this specific pixel can comprise a plurality of colors, and this printing equipment includes first adder, second adder, door comparison means, subtracter, error diffusion device, output feedback device.First adder includes one first end and one second end, this first end system receives the color stage value of one of this specific pixel first color, this second end system receives one of this first color of diffusing to this specific pixel error diffusion value, revises the color range value with one of this first color of producing this specific pixel first; Second adder includes one first end and one second end, this first end system receives this first correction color range value of this first color, this second end system receives one of this first color of being fed back to this specific pixel output backoff values, revises the color range value with one of this first color of producing this specific pixel second; The door comparison means includes one first end and one second end, this color range value of this first color of this first end system this specific pixel of reception is to produce one first threshold value and one second threshold value, this second end system receives this second correction color range value of this first color, this door comparison means is this second this first threshold value and this second threshold value of revising color range value and this first color of this first color relatively, with one of this first color of producing this specific pixel two-value numerical value; Subtracter includes one first end and one second end, this first end system receives this first correction color range value of this first color of this specific pixel, this second end system receives this two-value numerical value of this first color of this specific pixel, with one of this first color of producing this specific pixel error amount; The error diffusion device includes one first end and one second end, this color range value of this first color of this first end system this specific pixel of reception is to produce one first error diffusion weighted value and one second error diffusion weighted value, this second end system receives this error amount of this first color of this specific pixel, with one of this first color of producing this specific pixel error diffusion value; The output feedback device includes one first end and one second end, this first end system receives this color range value of this first color of this specific pixel and exports the feedback weighted value to produce one first output feedback weighted value and one second, this second end system receives this two-value numerical value of this first color of this specific pixel, with one of this first color of producing this specific pixel output backoff values.Wherein, printing equipment is a laser printer or a multifunctional paper feeding machine.
Green noise error diffusion method based on tone dependency of the present invention and related printing apparatus improvement prior art thereof can improve the image fault of the regular lines on bright color range, middle color range and dark rank, and then promote the quality of image printing.
Description of drawings
The present invention will be described in detail below with reference to accompanying drawings, and in conjunction with the embodiments and description:
Fig. 1 is the schematic diagram of the function mode of the traditional green noise error method of diffusion of explanation.
Fig. 2 is the schematic diagram of the function mode of the traditional green noise error method of diffusion of explanation.
Fig. 3 is the schematic diagram of the present invention in order to one of the printing equipment embodiment that handles an input image.
Fig. 4 A is the broken line graph of each numerical value of door comparison means shown in Figure 3.
Fig. 4 B is the broken line graph of each numerical value of error diffusion device shown in Figure 3.
Fig. 4 C is the broken line graph of each numerical value of output feedback device shown in Figure 3.
Fig. 5 (including Fig. 5 A and Fig. 5 B) is the distribution schematic diagram of each weighted value of error diffusion device shown in Figure 3 and output feedback device.
Fig. 6 is the schematic diagram of the present invention's one two-value image.
Fig. 7 is the flow chart of one of green noise error diffusion method based on tone dependency of the present invention example operation.
Embodiment
Please refer to Fig. 3, Fig. 3 is the schematic diagram of the present invention in order to one of the printing equipment 300 of handling continuous tone input image embodiment, this continuous tone input image system is arranged in a two-dimensional array, and with (x, y) represent this continuous tone to import the position of one of image specific pixel, this specific pixel comprises three colors, for example cyan, carmetta, yellow, its color range value use respectively C (x, y), M (x, y), Y (x, y) expression, (x y) illustrates present embodiment, in like manner applicable to carmetta and yellow with cyan C.As shown in Figure 3, printing equipment 300 includes (but being not limited to) first adder 310, second adder 320, door comparison means 330, subtracter 340, error diffusion device 350 and output feedback device 360.
Door comparison means 330 includes one first end and one second end, and the color range value C of this cyan of this first end system this specific pixel of reception (x, y), to produce one first threshold value t1 and one second threshold value t2.Please in the lump with reference to figure 4A, Fig. 4 A is the t1 of door comparison means 330 shown in Figure 3 and the threshold value broken line graph of t2, and (x y) can obtain a corresponding threshold value by the color range value C of cyan.This second end system receives this second correction color range value C12 (x of this cyan, y), this door comparison means 320 is this second correction color range value C12 (x of this cyan relatively, y) and this first threshold value t1 of this cyan and this second threshold value t2, with one of this cyan of producing this specific pixel output two-value numerical value D (x, y).
Note that above-mentioned printing equipment 300 can be a laser printer or a multifunctional paper feeding machine, but the present invention is not limited thereto.
Please note the first above-mentioned threshold value t again
1More than or equal to the second threshold value t
2, then when this cyan of this specific pixel this second revise color range value C12 (x, during y) greater than this first threshold value t1, then export one first numerical value D1 as this output two-value numerical value D of this cyan of this specific pixel (x, y); When this cyan of this specific pixel this second revise color range value C12 (x, during y) less than this second threshold value t2, then export a second value D2 as this output two-value numerical value D of this cyan of this specific pixel (x, y); And this second correction color range value C12 (x that works as this cyan of this specific pixel, y) in the time of between this first threshold value t1 and this second threshold value t2, then according to a two-value image (for example Fig. 6 is the schematic diagram of a two-value image) decide this cyan of this specific pixel this output two-value numerical value D (x, y).
The first above-mentioned numerical value D1 can be set at 255, and second value D2 can be set at 0, but the present invention is not limited thereto.
Note that each above-mentioned parameter (comprises a1, a2, b1, b2, t
1, t
2) can be set in a fixed numbers, to carry out follow-up running.
Please refer to Fig. 7, Fig. 7 is the flow chart of one of green noise error diffusion method based on tone dependency of the present invention example operation, its comprise following step (if note that and can obtain roughly the same result, then the following step and non-limiting will be according to shown in Figure 7 carrying out in proper order):
Step 702: beginning.
Step 704: the color range value of one of one of continuous tone input image specific pixel first color.
Step 706: this color range value according to this first color of this specific pixel produces one of this first color first output feedback weighted value and one second output feedback weighted value.
Step 708: carry out an output feedback operation according to this first output feedback weighted value of this first color of this specific pixel and this second output feedback weighted value and revise the color range value to produce one of this first color.
Step 710: according to this color range value of this first color of this specific pixel to produce one of this first color first threshold value and one second threshold value.
Step 712: judge that whether this correction color range value is greater than this first threshold value.If this revises the color range value greater than this first threshold value, execution in step 720; Otherwise, execution in step 730.
Step 720: export one first numerical value.Execution in step 760.
Step 730: judge that whether this correction color range value is less than this second threshold value.If this revises the color range value less than this second threshold value, execution in step 740; Otherwise, execution in step 750.
Step 740: export a second value.Execution in step 760.
Step 750: this output two-value numerical value that decides this first color of this specific pixel according to a two-value image.Execution in step 760.
Step 760: according to this color range value of this first color of this specific pixel to produce one of this particular color value first error diffusion weighted value and one second error diffusion weighted value.
Step 762: being somebody's turn to do of this first color according to this specific pixel exported two-value numerical value and this first error diffusion weighted value and this second error diffusion weighted value, carries out an error diffusion operation.
Step 764: judge whether to finish whole continuous tone input image.If finished whole continuous tone input image, execution in step 766; Otherwise, get back to step 704.
Step 766: finish.
About each assembly that each step shown in Figure 7 please be arranged in pairs or groups shown in Figure 3, can understand between each assembly and how to operate, and for description for purpose of brevity, so the operation of each step just repeats no more among Fig. 7.It should be noted that, the step of above-mentioned flow process only for the present invention for feasible embodiment, and unrestricted restrictive condition of the present invention, and under the situation of the present invention's spirit, the method can comprise other intermediate steps in addition or several steps can be merged into one step, to do suitable variation.
Above-described embodiment only is used for illustrating the present invention's technical characterictic, is not the category that is used for limiting to the present invention.Green noise error diffusion method based on tone dependency that the present invention disclosed and related printing apparatus improvement prior art thereof can improve the image fault of the regular lines on bright color range, middle color range and dark rank, and then promote the quality of image printing.
The above only is the present invention's preferred embodiment, and all equalizations of being done according to the present patent application claim change and modify, and all should belong to the present invention's covering scope.
Claims (14)
1. green noise error diffusion method based on tone dependency, in order to handle continuous tone input image, this continuous tone input image system is arranged in a two-dimensional array, and with (x, y) represent this continuous tone to import the position of one of image specific pixel, this specific pixel can comprise a plurality of colors, and this method includes following steps:
Color stage value according to one of this specific pixel first color produces one of this first color first output feedback weighted value and one second output feedback weighted value;
Carry out an output feedback operation according to this first output feedback weighted value of this first color of this specific pixel and this second output feedback weighted value and revise the color range value to produce one of this first color;
According to this color range value of this first color of this specific pixel to produce one of this first color first threshold value and one second threshold value;
Decide one of this first color output two-value numerical value according to this correction color range value of this first color of this specific pixel and this first threshold value and this second threshold value;
According to this color range value of this first color of this specific pixel to produce one of this color value first error diffusion weighted value and one second error diffusion weighted value; And
Being somebody's turn to do of this first color according to this specific pixel exported two-value numerical value and this first error diffusion weighted value and this second error diffusion weighted value, carries out an error diffusion operation.
2. the method for claim 1 is characterized in that, carries out this output feedback operation and comprises with the step of this correction color range value of this first color of producing this specific pixel:
According to one of this first output feedback weighted value of this first color of the color stage value of this first color of one of this specific pixel neighborhood pixels and this specific pixel and this first color value that this second output feedback weighted value produces this specific pixel output backoff values; And
This color range value of this first color of this specific pixel is added that this output backoff values of this first color is to produce this correction color range value of this first color.
3. method as claimed in claim 2 is characterized in that, this neighborhood pixels for the position that is positioned at this two-dimensional array (x-1, y) and position (x, pixel y-1).
4. the method for claim 1, it is characterized in that, this first threshold value of this first color of this specific pixel is more than or equal to this second threshold value, and decides the step of this output two-value numerical value of this first color to comprise according to this correction color range value and this first threshold value and this second threshold value:
When this first color of this specific pixel should revise color range value greater than this first threshold value the time, then export one first numerical value this output two-value numerical value as this first color of this specific pixel;
When this first color of this specific pixel should revise color range value less than this second threshold value the time, then export a second value this output two-value numerical value as this first color of this specific pixel; And
When this first color of this specific pixel should revise color range value between this first threshold value and this second threshold value the time, then decide this output two-value numerical value of this first color of this specific pixel according to a two-value image.
5. method as claimed in claim 4 is characterized in that, this first numerical value is 255.
6. method as claimed in claim 4 is characterized in that, this second value is 0.
7. the method for claim 1 is characterized in that, the step of carrying out this error diffusion operation comprises:
This color range value of this first color of this specific pixel is deducted this output two-value numerical value of this first color to produce one of this first color error amount; And
This first error weighted value and this second error weighted value according to this first color of this specific pixel spread this error amount to this first color of one of this specific pixel neighborhood pixels.
8. method as claimed in claim 7 is characterized in that, this neighborhood pixels for the position that is positioned at this two-dimensional array (x+1, y) and position (x, pixel y+1).
9. the method for claim 1 is characterized in that, these a plurality of colors comprise cyan, carmetta, yellow.
10. one kind is used for handling the printing equipment that a continuous tone is imported image, this continuous tone input image system is arranged in a two-dimensional array, and so that (on behalf of this continuous tone, x y) import the position of one of image specific pixel, this specific pixel can comprise a plurality of colors, and this printing equipment includes:
One first adder, include one first end and one second end, this first end system receives the color stage value of one of this specific pixel first color, this second end system receives one of this first color of diffusing to this specific pixel error diffusion value, revises the color range value with one of this first color of producing this specific pixel first;
One second adder, include one first end and one second end, this first end system receives this first correction color range value of this first color, this second end system receives one of this first color of being fed back to this specific pixel output backoff values, revises the color range value with one of this first color of producing this specific pixel second;
One door comparison means, include one first end and one second end, this color range value of this first color of this first end system this specific pixel of reception is to produce one first threshold value and one second threshold value, this second end system receives this second correction color range value of this first color, this door comparison means is this second this first threshold value and this second threshold value of revising color range value and this first color of this first color relatively, with one of this first color of producing this specific pixel two-value numerical value;
One subtracter, include one first end and one second end, this first end system receives this first correction color range value of this first color of this specific pixel, this second end system receives this two-value numerical value of this first color of this specific pixel, with one of this first color of producing this specific pixel error amount;
One error diffusion device, include one first end and one second end, this color range value of this first color of this first end system this specific pixel of reception is to produce one first error diffusion weighted value and one second error diffusion weighted value, this second end system receives this error amount of this first color of this specific pixel, with one of this first color of producing this specific pixel error diffusion value; And
One output feedback device, include one first end and one second end, this first end system receives this color range value of this first color of this specific pixel and exports the feedback weighted value to produce one first output feedback weighted value and one second, this second end system receives this two-value numerical value of this first color of this specific pixel, with one of this first color of producing this specific pixel output backoff values.
11. printing equipment as claimed in claim 10 is characterized in that, this first threshold value is greater than or equal to this second threshold value, and this door comparison means is used for:
When this of this first color of this specific pixel second when revising color range value, then export one first numerical value this output two-value numerical value as this first color of this specific pixel greater than this first threshold value;
When this of this first color of this specific pixel second when revising color range value, then export a second value this output two-value numerical value as this first color of this specific pixel less than this second threshold value; And
Second revise color range value between this first threshold value and this second threshold value the time when this of this first color of this specific pixel, then decide this output two-value numerical value of this first color of this specific pixel according to a two-value image.
12. the printing equipment as described in the claim 11 is characterized in that this first numerical value is 255.
13. the printing equipment as described in the claim 11 is characterized in that second value is 0.
14. the printing equipment as described in the claim 10 is characterized in that it is a laser printer or a multifunctional paper feeding machine.
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Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
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CN102158630A (en) * | 2011-05-31 | 2011-08-17 | 武汉大学 | Image-tone-based adaptive green-noise screening method |
CN105635523A (en) * | 2015-12-30 | 2016-06-01 | 珠海奔图电子有限公司 | Image processing method, image processing device and image forming device |
CN109421264A (en) * | 2017-08-30 | 2019-03-05 | 三纬国际立体列印科技股份有限公司 | Ink ejecting method and three-dimensional printing device |
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2009
- 2009-01-22 CN CNA200910037014XA patent/CN101489023A/en active Pending
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
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CN102158630A (en) * | 2011-05-31 | 2011-08-17 | 武汉大学 | Image-tone-based adaptive green-noise screening method |
CN102158630B (en) * | 2011-05-31 | 2012-10-10 | 武汉大学 | Image-tone-based adaptive green-noise screening method |
CN105635523A (en) * | 2015-12-30 | 2016-06-01 | 珠海奔图电子有限公司 | Image processing method, image processing device and image forming device |
CN105635523B (en) * | 2015-12-30 | 2018-08-10 | 珠海赛纳打印科技股份有限公司 | Image processing method, image processing apparatus and image forming apparatus |
CN109421264A (en) * | 2017-08-30 | 2019-03-05 | 三纬国际立体列印科技股份有限公司 | Ink ejecting method and three-dimensional printing device |
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