CN103595895A - Color correction method and image processing apparatus - Google Patents
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Abstract
The invention provides a color correction method and an image processing device. The method comprises the following steps: obtaining a first image of a guide table, wherein the guide table comprises a plurality of color blocks, and each color block corresponds to a standard value; obtaining a plurality of first measurement values according to the first image, wherein each first measurement value corresponds to one of the standard values; generating a calibration table according to the first measurement value and the standard value; and determining whether a recurrence condition is satisfied. The method further comprises: if the recursive condition is not satisfied, a second image of the derivative table is obtained, a plurality of second measurement values are obtained according to the second image, the second measurement values are adjusted according to the correction table to generate a plurality of third measurement values, and the correction table is updated according to the third measurement values and the standard values until the recursive condition is satisfied. Therefore, the method can automatically generate the correction table.
Description
Technical field
The invention relates to a kind of color calibration method and image processing apparatus.
Background technology
In general, when a scanner obtains an image for an object, the brightness of object reality might not equal the brightness in obtained image.Between the brightness of object and the brightness of image, can exist nonlinear distortion (distortion).This distortion can represent with following equation (1).
Y?∝X
γ...(1)
The brightness value that wherein X is object, the brightness value that Y is image, γ is a parameter.Because exist above-mentioned non-linear relation when obtaining image, so scanner can be done gamma correction to the brightness in this image (luminance) or colourity (chrominance) after obtaining image, and (gamma correction) removes such distortion.Gamma correction is to carry out the error in compensating images in nonlinear mode, makes the brightness value of object and the brightness value after image rectification linear.Gamma correction can represent with following equation (2).
Y′∝Y
1/γ...(2)
Wherein Y ' is the brightness value through gamma correction.γ is the parameter that gamma correction is used.Therefore,, after the computing of equation (2), between Y ' and X, just can become linear relation.
In order to reach the effect of above-mentioned gamma correction, common way has matching test and digital.The way of matching test is to utilize nonlinear electronic circuit to produce the operation result of approximate aforesaid equation (2).
Digital way is directly to calculate the exponent arithmetic of aforesaid equation (2).Yet, on some devices, can not do in real time exponent arithmetic, therefore precalculated input and output can be stored in a look-up table (lookup table).In the time that gamma correction will be carried out, just can obtain the brightness value after adjustment by inquiring about this look-up table.
It is very efficient only utilizing a γ cover to be used on different scanners.But the numerical value of a γ might not be applicable to all scanners.If will produce corresponding γ by artificial mode for each scanner, can spend very many time.Therefore, how to produce automatically the γ subject under discussion that area research personnel are concerned about for this reason.
Summary of the invention
Embodiments of the invention provide a kind of color calibration method and image processing apparatus, can produce automatically a checking list.
One embodiment of the invention provides a kind of color calibration method, for image processing apparatus.Color calibration method comprises: obtain first image of leading table, this leads table and comprises a plurality of color lumps, and the corresponding standard value of each color lump; According to the first image, obtain a plurality of the first measured values, wherein one of them of the corresponding above-mentioned standard value of each the first measured value; According to the first measured value and standard value, produce a checking list; And whether the judgement condition of pulling over meets.This color calibration method also comprises: if the condition of pulling over does not meet, obtain second image of leading table, according to the second image, obtain a plurality of the second measured values, according to checking list, adjust the second measured value to produce a plurality of the 3rd measured values, and upgrade checking list until meet the condition of pulling over according to the 3rd measured value and standard value.
In one embodiment, above-mentioned checking list comprises a plurality of the first output valves, corresponding first index of each first output valve.The above-mentioned step according to the first measured value and standard value generation checking list comprises: the first index of setting section is the first measured value; The first output valve of setting corresponding the first measured value is standard value; And, the first output valve of not corresponding the first measured value of generation.
In one embodiment, the above-mentioned judgement whether satisfied step of condition of pulling over comprises: judge whether the number of times of pulling over meets the critical value of pulling over; And number of times meets the critical value of pulling over if this pulls over, judge that the condition of pulling over is satisfied.The above-mentioned step according to the 3rd measured value and standard value renewal checking list also comprises: upgrade the number of times of pulling over.
In one embodiment, the above-mentioned judgement whether satisfied step of condition of pulling over comprises: according to the first measured value and standard value, calculate an error amount, or calculate this error amount according to the 3rd measured value and standard value; Judge whether this error amount is less than an error critical value; And, if error amount is less than error critical value, judge that the condition of pulling over is satisfied.
In one embodiment, the first above-mentioned measured value comprises a minimum measured value and a greatest measurement.The step of the first output valve of not corresponding the first measured value of above-mentioned generation comprises: corresponding the first output valve of the first index that setting is less than minimum measured value is the first preset value; Corresponding the first output valve of the first index that setting is greater than greatest measurement is the second preset value; And produce remaining first output valve with an interpolative operation method.
In one embodiment, the first above-mentioned index comprises second index, and the second index corresponds to second output valve in the first output valve.The above-mentioned step according to the 3rd measured value and standard value renewal checking list comprises: set up a temporary transient checking list, this temporary transient checking list comprises a plurality of the 3rd output valves, and corresponding the 3rd index of each the 3rd output valve; The 3rd index of setting section is the 3rd described measured value; The 3rd output valve of setting corresponding the 3rd measured value is standard value; Produce the 3rd output valve that does not correspond to the 3rd measured value; One of them using the second output valve as the 3rd index is to obtain the 4th output valve in the 3rd output valve; And to set the second output valve be the 4th output valve.Therefore,, by the second index and the second output valve, can produce the checking list after renewal.
In one embodiment, the above-mentioned step of calculating an error amount according to the first measured value and standard value comprises: calculate residual sum of squares (RSS) between the first measured value and standard value to obtain this error amount.The above-mentioned step according to the 3rd measured value and standard value error of calculation value comprises: calculate residual sum of squares (RSS) between the 3rd measured value and standard value to obtain error amount.
From another one angle, one embodiment of the invention provides a kind of image processing apparatus, comprises image acquisition unit and processor.Image acquisition unit is to obtain first image of leading table.This leads table and comprises a plurality of color lumps, and the corresponding standard value of each color lump.Processor is to be coupled to image acquisition unit, in order to obtain a plurality of the first measured values according to the first image, and one of them of the corresponding above-mentioned standard value of each the first measured value wherein.Processor is in order to produce a checking list according to the first measured value and standard value, and judges whether the condition of pulling over meets.If pull over, condition does not meet, processor is also in order to obtain second image of leading table, according to the second image, obtain a plurality of the second measured values, according to checking list, adjust the second measured value to produce a plurality of the 3rd measured values, and upgrade checking list until meet the condition of pulling over according to the 3rd measured value and standard value.
In one embodiment, above-mentioned checking list comprises a plurality of the first output valves, and corresponding first index of each first output valve.Processor is also the first measured value in order to the first index of setting section, and the first output valve of setting corresponding the first measured value is standard value, and produces the first output valve that does not correspond to the first measured value.
In one embodiment, above-mentioned processor is also in order to judge whether the number of times of pulling over meets the critical value of pulling over.If pull over, number of times meets the critical value of pulling over, and processor is also satisfied in order to judge the condition of pulling over.Processor also, in order to when according to the 3rd measured value and standard value renewal checking list, upgrades the number of times of pulling over.
In one embodiment, above-mentioned processor is also in order to calculate an error amount according to the first measured value and standard value, or calculates this error amount according to the 3rd measured value and standard value.Processor is also in order to judge whether this error amount is less than an error critical value.If error amount is less than error critical value, processor is also satisfied in order to judge the condition of pulling over.
In one embodiment, the first above-mentioned measured value comprises a minimum measured value and a greatest measurement.Processor is also less than minimum measured value corresponding the first output valve of the first index in order to set is first preset value, corresponding the first output valve of the first index that setting is greater than greatest measurement is second predicted value, and produces remaining first output valve with interpolative operation method.
In one embodiment, the first above-mentioned index comprises second index, and this second index corresponds to second output valve in above-mentioned the first output valve.Processor is also in order to set up a temporary transient checking list, and this temporary transient checking list comprises a plurality of the 3rd output valves, and corresponding the 3rd index of each the 3rd output valve.Processor is also the 3rd measured value in order to the 3rd index of setting section, the 3rd output valve of setting corresponding the 3rd measured value is standard value, produce the 3rd output valve that does not correspond to the 3rd measured value, one of them using the second output valve as the 3rd index to be to obtain the 4th output valve in the 3rd output valve, and set the second output valve the 4th output valve for this reason.Therefore,, by the second index and the second output valve, can produce the checking list after renewal.
In one embodiment, above-mentioned processor is also in order to calculate residual sum of squares (RSS) between the first measured value and standard value to obtain above-mentioned error amount.Or the residual sum of squares (RSS) between processor calculating the 3rd measured value and standard value is to obtain this error amount.
Based on above-mentioned, the color calibration method that the embodiment of the present invention provides and image processing apparatus, can produce automatically checking list and upgrade this checking list in the mode of pulling over.
For above-mentioned feature and advantage of the present invention can be become apparent, special embodiment below, and coordinate accompanying drawing to be described in detail below.
Accompanying drawing explanation
Fig. 1 illustrates the calcspar of image processing apparatus according to an embodiment;
Fig. 2 is according to the schematic diagram of an embodiment account for color corrective system;
Fig. 3 A and Fig. 3 B lead the example schematic of table according to an embodiment explanation;
Fig. 4 and Fig. 5 set up the schematic diagram of a checking list according to an embodiment explanation;
Fig. 6 to Fig. 9 illustrates according to an embodiment schematic diagram that upgrades checking list;
Figure 10 is according to the flow chart of an embodiment account for color bearing calibration;
Figure 11 is according to the flow chart of the second embodiment account for color bearing calibration.
Description of reference numerals:
100: image processing apparatus;
110: image acquisition unit;
120: processor;
130: memory;
132: color corrected system;
210: acquisition module;
220: correction module;
230: the module of pulling over;
300: lead table;
310 (1)～310 (A): color lump;
400: checking list;
410 (0)～410 (255): output valve;
420 (0)～420 (255): index;
700: temporary transient checking list;
710 (0)～710 (255): output valve;
720 (0)～720 (255): index;
S1002, S1004, S1006, S1008, S1010, S1012, S1014, S1102, S1104, S1106, S1108, S1110, S1112, S1114: the step of color calibration method.
Embodiment
[the first embodiment]
Fig. 1 illustrates the calcspar of image processing apparatus according to an embodiment.
Please refer to Fig. 1, image processing apparatus 100 comprises image acquisition unit 110, processor 120 and memory 130.For example, image processing apparatus 100 can be set to scanner, digital still camera, digit camera, computer or server.
Fig. 2 is according to the schematic diagram of an embodiment account for color corrective system.
Please refer to Fig. 2, color corrected system 132 comprises acquisition module 210, correction module 220 and the module 230 of pulling over.
Fig. 3 A and Fig. 3 B lead the example schematic of table according to an embodiment explanation.
Please refer to Fig. 3 A and Fig. 3 B, lead table 300 and comprised color lump 310 (1)～310 (A).Color in a color lump is all identical, and a color lump can correspond to a standard value.For instance, color lump 310 (1) is to correspond to standard value " 0 ", and color lump 310 (2) is to correspond to standard value " 11 ", by that analogy.Leading table 300 is color lumps 310 (1)～310 (A) that standard is provided, and allows image processing apparatus 100 produce checking list according to these color lumps 310 (1)～310 (A) and corresponding standard value.
In this embodiment, each standard value means the numerical value of brightness.For example, yet in other embodiments, each standard value also can mean the numerical value of chroma (, red, green, blue).Or, each square also can be corresponding other standard value, the present invention is not subject to the limits.
In order to produce checking list, acquisition module 210 can be obtained an image of leading table 300, and can obtain a plurality of measured values (also claiming the first measured value) according to this image.For instance, acquisition module 210 can be obtained the color value of a plurality of pixels in the region of corresponding color lump 310 (1) in image.Acquisition module 210 can calculate the average of these color values, the measured value " 2 " of usining as corresponding color lump 310 (1).Similarly, acquisition module 210 also can be obtained the color value of a plurality of pixels in the region of corresponding color lump 310 (2) in image, and calculates the measured value " 4 " of on average usining as corresponding color lump 310 (2) of these color values, by that analogy.
Yet due to the error on some hardware or noise, the measured value that corresponds to same color lump might not be identical with standard value.For example, measured value " 2 " and standard value " 0 " are all to correspond to color lump 310 (1), but between error be 2; Measured value " 4 " and standard value " 11 " are all to correspond to color lump 310 (2), but between error be 7.Correction module 220 can produce checking list according to these measured values and standard value shown in Fig. 3 B.
Fig. 4 and Fig. 5 set up the schematic diagram of a checking list according to an embodiment explanation.
Please refer to Fig. 4, checking list 400 has comprised output valve 410 (0)～410 (255), and these output valves 410 (0)～410 (255) correspond to respectively index 420 (0)～420 (255).The running of checking list 400 is: when a numerical value of input, correction module 220 can be assigned this numerical value as the index of checking list 400 and export corresponding output valve.For instance, if the numerical value of input is " 2 ", this numerical value can be taken as index 420 (2), and exports corresponding output valve 410 (2).
When setting up checking list 400, the index 420 (0)～420 (255) of correction module meeting setting section is the measured value shown in Fig. 3 B, and the output valve of corresponding these measured values of setting is above-mentioned standard value.For instance, standard value " 0 " is to correspond to measured value " 2 ", thus correction module 220 can to set index 420 (2) be measured value " 2 ", and setting output valve 410 (2) is standard value " 0 ".Standard value " 11 " is the amount of corresponding to side value " 4 ", thus correction module 220 to set index 420 (4) be measured value " 4 ", and the output valve 410 (4) of this measured value of correspondence just can be set to standard value " 11 ".Standard value " 22 " is to correspond to measured value " 5 ", thus correction module 220 can to set index 420 (5) be measured value " 5 ", and setting output valve 410 (5) is standard value " 22 ".In the present embodiment, the number of standard value is 24, therefore only has 24 output valves (for example, output valve 410 (2), 410 (4), 410 (5) and 410 (204)) can be set to corresponding standard value.Correction module 220 also can produce the output valve that does not correspond to measured value.Specifically, correction module 220 can first be obtained one (also claiming minimum measured value, i.e. measured value " 2 ") minimum in measured value, and obtains wherein one (also claiming greatest measurement, i.e. measured value " 204 ") of maximum.The corresponding output valve 410 (0) of index 420 (0)～420 (1) that correction module 220 meeting settings are less than minimum measured value is first preset value with 410 (1).It is second preset value that correction module 220 also can be set the corresponding output valve 410 (205)～410 (255) of index 420 (205)～420 (255) that is greater than greatest measurement.For example, and correction module 220 can produce remaining output valve (, output valve 410 (3)) with an interpolative operation method.
Please refer to Fig. 5, in this embodiment, it is 0 that correction module 220 is set the first preset values, and to set the second preset value be 255.In other words, output valve 410 (0) can be set to " 0 " with 410 (1); And output valve 410 (205)～410 (255) can be set to " 255 ".Correction module 220 can be carried out an interpolative operation method according to output valve 410 (2) and 410 (4) and produce output valve 410 (3).For example, correction module 220 can calculate output valves 410 (2) with 410 (4) on average to produce output valve 410 (3).
Yet in other embodiments, correction module 220 also can be carried out interpolative operation method with a low pass filter.Or correction module 220 can produce an exponential function or polynomial function according to output valve 410 (2), 410 (4), 410 (5) and 410 (204) etc.Correction module 220 can calculate output valve 410 (3) according to the function producing, and the present invention is also not subject to the limits.In addition,, when the color value of a pixel is when more multibyte (that is, being greater than 8 bytes) represents, checking list 400 can comprise more index and output valve.And the first preset value can be set to different numerical value from the second preset value, the present invention is also not subject to the limits.
After calculating checking list 400, the module of pulling over 230 can judge whether the condition of pulling over meets.If this pulls over, condition meets, and correction module 220 can output calibration table 400.After this, after acquisition module 210 is obtained an image, correction module 220 just can be adjusted the color value in this image according to checking list 400.Yet when the condition of pulling over is not satisfied, the renewal checking list 400 that correction module 220 can be lasting, until the condition of pulling over is satisfied.
In upgrading the process of checking list 400, acquisition module 210 can be obtained and leads another image (also claiming the second image) of table 300 and obtain a plurality of measured values (also claiming the second measured value) according to this image.Correction module 220 can be adjusted these second measured values to produce a plurality of measured values (also claiming the 3rd measured value) according to current checking list 400.Correction module 220 can upgrade checking list 400 according to standard value and these the 3rd measured values, until the module 230 judgement conditions of pulling over of pulling over are satisfied.
Fig. 6 to Fig. 9 illustrates according to an embodiment schematic diagram that upgrades checking list.
Please refer to Fig. 6, corresponding to color lump 310 (1)～310 (3), with 310 (A), the second measured value that acquisition module 210 is obtained is respectively " 0 ", " 3 ", " 5 " ... " 204 ".Correction module 220 can be adjusted these second measured values to produce the 3rd measured value " 0 ", " 6 ", " 22 " according to checking list 400 ... " 255 ".For instance, correction module 220 is the index as checking list 400 by " 3 ", can obtain output valve " 6 "; Correction module 220 is the index as checking list 400 by " 5 ", can obtain output valve " 22 ".It should be noted that acquisition module 210 is for same color lump, twice obtained measured value might not be identical.For instance, for color lump 310 (2), the measured value that acquisition module 210 is obtained is for the first time " 4 " (as shown in Figure 3 B), but the measured value of obtaining is for the second time " 3 ".
Please refer to Fig. 7, temporary transient checking list 700 comprises output valve 710 (0)～710 (255), and output valve 710 (0)～710 (255) corresponds to respectively index 720 (0)～720 (255).Correction module 220 can be set index 720 (0), 720 (6), 720 (22) and 720 (255) and be respectively the 3rd measured value " 0 ", " 6 ", " 22 " and " 255 ".And output valve 710 (0), 710 (6), 710 (22), be corresponding standard value " 0 ", " 11 ", " 22 " and " 255 " with 710 (255).
Please refer to Fig. 8, correction module 220 can calculate according to an interpolative operation method and not correspond to the output valve 710 (1)～710 (5) of the 3rd measured value, with 710 (11).For example, correction module 220 produces output valve 710 (11) in the mode of linear interpolation, and its value is " 14 ".
With another one angle, checking list 400 can represent in order to lower equation (3) and (4) with temporary transient checking list 700.
M
n＝{m
n，0，m
n，1，...，g
n，255}...(3)
G
n＝{g
n，0，g
n，1，...，g
n，255}...(4)
Wherein, M
nchecking list 400 while representing to upgrade for the n time, n is positive integer.M
n, 0be illustrated in while upgrading for the n time, the 0th output valve 410 (0) in checking list 400, by that analogy.G
nthe temporary transient checking list 700 producing while representing to upgrade for the n time, and g
n, 0be illustrated in while upgrading for the n time, the 0th output valve 710 (0) in temporary transient checking list 700, by that analogy.The step that checking list 400 and temporary transient checking list 700 is synthetic can represent in order to lower equation (5)～(7).
M
n+1＝{m
n+1，0，m
n+1，1，...，m
n+1，255}...(5)
m
n+1，j＝g
n，t...(6)
t＝m
n，j...(7)
In other words, j output valve m in the checking list 400 upgrading for the n time
n, jcan be taken as index value t.Correction module 220 can find according to this index value t the output valve g of temporary transient checking list 700
n, t.Output valve g
n, tcan be taken as j output valve m in the checking list 400 while upgrading for the n+1 time
n+1, j.
The step of above-mentioned renewal checking list 400 can be repeated, until the module 230 judgement conditions of pulling over of pulling over are satisfied.In one embodiment, the module of pulling over 230 can judge whether the number of times of pulling over meets the critical value of pulling over, and if so, judges that the condition of pulling over is satisfied.When each checking list 400 is updated, the number of times of pulling over all can be updated.For instance, the initial value of the number of times of pulling over is 0, and the number of times of pulling over when each checking list 400 is updated can be increased 1, and the critical value of pulling over is 3.When the number of times of pulling over is more than or equal to 3, the module of pulling over 230 can judge that the number of times of pulling over has met the critical value of pulling over.In other words, if checking list 400 is updated after 3 times, just the condition of pulling over is satisfied.Yet in other embodiments, the initial value of the number of times of pulling over is 3, the number of times of pulling over when each checking list 400 is updated can be reduced 1, and the critical value of pulling over is 0, and the module 230 of pulling over when the number of times of pulling over is less than or equal to 0 can judge that the number of times of pulling over meets the critical value of pulling over.Yet the critical value of pulling over also can be set to 5,10 or other numerical value, the present invention is also not subject to the limits.
In one embodiment, after producing or upgrading checking list 400, the module of pulling over 230 can be calculated an error amount between measured value and standard value.If this error amount is less than an error critical value, the module of pulling over 230 can the judgement condition of pulling over be satisfied.For instance, pull over module 230 can be carried out error of calculation value according to following equations (8).
Wherein, R
nit is the error amount while upgrading checking list 400 the n time.J and k are integer.K represents to lead the number of color lump in table 300.I
n, jbe illustrated in while upgrading checking list 400 the n time j the corresponding measured value of color lump.S
jrepresent j the corresponding standard value of color lump.It should be noted that and calculating R
1time, i
1, jdo not have adjustment (that is, the i through checking list
1, jbe the first measured value).Calculating R
2time, i
2, jcan pass through checking list M
1adjustment (that is, i
2, jbe the 3rd measured value, rather than the second measured value).Produce checking list M at every turn
nafter, the module of pulling over 230 just can be calculated and error in judgement value R
nwhether be less than an error critical value.If error amount R
nbe less than this error critical value, the module of pulling over 230 can judge that the condition of pulling over is satisfied, and output calibration table M
n.
That above equation (8) calculates is residual sum of squares (RSS) (sum of squared error).Yet in other embodiments, the module of pulling over 230 also can be used mean square deviation (mean squared error) or absolute residuals and (sum of absolute error) to carry out error of calculation value, the present invention is also not subject to the limits.
In the present embodiment, when error amount is less than error critical value or the number of times of pulling over, meet while pulling over critical value, the module of pulling over 230 can the judgement conditions of pulling over be satisfied.Yet in other embodiments, the module of pulling over 230 also can be less than error critical value and the number of times of pulling at error amount and meet while pulling over critical value, just the judgement condition of pulling over is satisfied.
Figure 10 is according to the flow chart of an embodiment account for color bearing calibration.
Please refer to Figure 10, in step S1002, acquisition module 210 can be obtained first image of leading table.This leads table and comprises a plurality of color lumps, and the corresponding standard value of each color lump.
In step S1004, acquisition module 210 can be obtained a plurality of the first measured values according to the first image, wherein the corresponding standard value of each first measured value.
In step S1006, correction module 220 can produce checking list according to the first measured value and standard value.
In step S1008, the module of pulling over 230 can judge that whether the condition of pulling over is satisfied.If pull over, condition is satisfied, can finish this flow process.
If pull over, condition is not yet satisfied, and in step S1010, acquisition module 210 can be obtained second image of leading table, and obtains a plurality of the second measured values according to the second image.In step S1012, correction module 220 can be adjusted the second measured value to produce a plurality of the 3rd measured values according to checking list.In step S1014, correction module 220 can upgrade checking list according to the 3rd measured value and standard value.
Yet each step has described in detail as above in Figure 10, at this, just do not repeat repeating.
[the second embodiment]
The second embodiment and the first embodiment are similar, at this, difference are only described.In the first embodiment, when acquisition module 210 is obtained measured value for the first time, correction module 220 can't utilize checking list to adjust these the first measured values.Yet in a second embodiment, after acquisition module 210 is obtained measured value each time, correction module 220 all can be adjusted these measured values according to checking list.
Figure 11 is according to the flow chart of the second embodiment account for color bearing calibration.
Please refer to Figure 11, in step S1102, making program at the beginning of correction module 220 can be carried out with the module 230 of pulling over.Correction module 220 can be set an initial checking list, and each output valve wherein can equal corresponding index.That is, in a second embodiment, the m in aforesaid equation (3)
1, ican equal i.The module of pulling over 230 can be set pull over critical value and error critical value.
In step S1104, acquisition module 210 can be obtained an image of leading table 300, and obtains a plurality of measured values of this image.
In step S1106, correction module 220 can be adjusted these measured values according to checking list.It should be noted that when step S1106 is performed for the first time, because the output valve in checking list equals corresponding index, the measured value after therefore adjusting is identical with the measured value before adjustment.
In step S1108, the module of pulling over 230 can be carried out error of calculation value by the measured value according to standard value and after adjusting.That is, in a second embodiment, each measured value i in aforesaid equation (8)
n, jall being corrected module 220 adjusted according to checking list.
In step S1110, whether the module of pulling over 230 can the judgement condition of pulling over meet.In a second embodiment, when error amount is less than error critical value or the number of times of pulling over, meet while pulling over critical value, the module of pulling over 230 condition of can judgement pulling over is satisfied.If the condition of pulling over is satisfied, the flow process of Figure 11 can be moved to end.
If the condition of pulling over is not yet satisfied, in step S1112, correction module 220 can produce temporary transient checking list by the measured value according to standard value and after adjusting.It should be noted that when step S1112 is performed for the first time, because the measured value after adjusting is identical with the measured value before adjustment, the temporary transient checking list therefore producing can be equal to the checking list (as shown in Figure 5) producing for the first time in the first embodiment.
In step S1114, correction module 220 can merge temporary transient checking list and checking list, and gets back to step S1104.It should be noted that when step S1114 is performed for the first time, merging the checking list can be identical with temporary transient checking list.Specifically, above-mentioned equation (6) can be rewritten as following equation (9) and (10) with (7).
t＝m
1，j＝j...(9)
m
2，j＝g
1，t＝g
1，j...(10)
In sum, color calibration method provided by the invention and image processing apparatus, can produce checking list by the mode of pulling over.Therefore minimizing convergence that, the error between measured value and standard value can be gradually.
Finally it should be noted that: each embodiment, only in order to technical scheme of the present invention to be described, is not intended to limit above; Although the present invention is had been described in detail with reference to aforementioned each embodiment, those of ordinary skill in the art is to be understood that: its technical scheme that still can record aforementioned each embodiment is modified, or some or all of technical characterictic is wherein equal to replacement; And these modifications or replacement do not make the essence of appropriate technical solution depart from the scope of various embodiments of the present invention technical scheme.
Claims (14)
1. a color calibration method, for an image processing apparatus, is characterized in that, this color calibration method comprises:
Obtain one first image of leading table, wherein this is led table and comprises a plurality of color lumps, and the corresponding standard values of each those color lump;
According to this first image, obtain a plurality of the first measured values, wherein one of them of each those corresponding those standard values of first measured values;
According to those first measured values and those standard values, produce a checking list;
Judge whether the condition of pulling over meets; And
If this is pulled over, condition does not meet, obtain one second image that this leads table, according to this second image, obtain a plurality of the second measured values, according to this checking list, adjust those second measured values to produce a plurality of the 3rd measured values, and upgrade this checking list until meet this condition of pulling over according to those the 3rd measured values and those standard values.
2. color calibration method according to claim 1, it is characterized in that, this checking list comprises a plurality of the first output valves, and each those corresponding one first index of first output valves wherein comprise according to the step that those first measured values and those standard values produce this checking list:
Those of setting section the first index is those first measured values;
Those first output valves of setting corresponding those the first measured values are those standard values; And
Produce not those first output valves of corresponding those the first measured values.
3. color calibration method according to claim 1, is characterized in that, judges that this whether satisfied step of condition of pulling over comprises:
Judge whether the number of times of pulling over meets the critical value of pulling over; And
If this is pulled over, number of times meets this critical value of pulling over, and judges that this condition of pulling over is satisfied;
The step of wherein upgrading this checking list according to those the 3rd measured values and those standard values also comprises:
Upgrade this number of times of pulling over.
4. color calibration method according to claim 1, is characterized in that, judges that this whether satisfied step of condition of pulling over comprises:
According to those first measured values and those standard values, calculate an error amount, or calculate this error amount according to those the 3rd measured values and those standard values;
Judge whether this error amount is less than an error critical value; And
If this error amount is less than this error critical value, judge that this condition of pulling over is satisfied.
5. color calibration method according to claim 2, is characterized in that, those first measured values comprise a minimum measured value and a greatest measurement, wherein produces the not step of those the first output valves of corresponding those the first measured values and comprises:
Corresponding those first output valves of those first index that setting is less than this minimum measured value are one first preset value;
Corresponding those first output valves of those first index that setting is greater than this greatest measurement are one second preset value; And
With an interpolative operation method, produce remaining those first output valve.
6. color calibration method according to claim 2, it is characterized in that, those first index comprise one second index, and this second index corresponds to one second output valve in those first output valves, the step of wherein upgrading this checking list according to those the 3rd measured values and those standard values comprises:
Set up a temporary transient checking list, wherein this temporary transient checking list comprises a plurality of the 3rd output valves, and corresponding one the 3rd index of each those the 3rd output valve;
Those of setting section the 3rd index is those the 3rd measured values;
Those the 3rd output valves of setting corresponding those the 3rd measured values are those standard values;
Produce those the 3rd output valves that do not correspond to those the 3rd measured values;
One of them using this second output valve as those the 3rd index is to obtain one the 4th output valve in those the 3rd output valves; And
Setting this second output valve is the 4th output valve.
7. color calibration method according to claim 4, is characterized in that, the step of calculating an error amount according to those first measured values and those standard values comprises:
Calculate a residual sum of squares (RSS) between those first measured values and those standard values to obtain this error amount;
The step of wherein calculating this error amount according to those the 3rd measured values and those standard values comprises:
Calculate a residual sum of squares (RSS) between those the 3rd measured values and those standard values to obtain this error amount.
8. an image processing apparatus, is characterized in that, comprising:
One image acquisition unit, in order to obtain one first image of leading table, wherein this is led table and comprises a plurality of color lumps, and the corresponding standard values of each those color lump; And
One processor, is coupled to this image acquisition unit, in order to obtain a plurality of the first measured values according to this first image, and one of them of each those corresponding those standard values of first measured values wherein;
Wherein, this processor is in order to produce a checking list according to those first measured values and those standard values, and judges whether the condition of pulling over meets;
Wherein, if this is pulled over, condition does not meet, one second image that this processor is led table in order to obtain this, according to this second image, obtain a plurality of the second measured values, according to this checking list, adjust those second measured values to produce a plurality of the 3rd measured values, and upgrade this checking list until meet this condition of pulling over according to those the 3rd measured values and those standard values.
9. image processing apparatus according to claim 8, is characterized in that, this checking list comprises a plurality of the first output valves, and corresponding one first index of each those first output valve;
Wherein, this processor is also those first measured values in order to those first index of setting section, and those first output valves of setting corresponding those the first measured values are those standard values, and produces those first output valves that do not correspond to those the first measured values.
10. image processing apparatus according to claim 8, is characterized in that, this processor is also in order to judge whether the number of times of pulling over meets the critical value of pulling over;
If this is pulled over, number of times meets this critical value of pulling over, and this processor is also satisfied in order to judge this condition of pulling over;
Wherein this processor, also in order to when upgrading this checking list according to those the 3rd measured values and those standard values, upgrades this number of times of pulling over.
11. image processing apparatus according to claim 8, is characterized in that, this processor is also in order to calculate an error amount according to those first measured values and those standard values, or calculate this error amount according to those the 3rd measured values and those standard values;
Wherein, this processor is also in order to judge whether this error amount is less than an error critical value;
If this error amount is less than this error critical value, this processor is also satisfied in order to judge this condition of pulling over.
12. image processing apparatus according to claim 9, it is characterized in that, those first measured values comprise a minimum measured value and a greatest measurement, this processor is also less than this minimum measured value corresponding those first output valves of those first index in order to set are one first preset value, corresponding those first output valves of those first index that setting is greater than this greatest measurement are one second predicted value, and produce remaining those first output valve with an interpolative operation method.
13. image processing apparatus according to claim 9, it is characterized in that, those first index comprise one second index, and this second index corresponds to one second output valve in those first output valves, wherein this processor is also in order to set up a temporary transient checking list, wherein this temporary transient checking list comprises a plurality of the 3rd output valves, and corresponding one the 3rd index of each those the 3rd output valve;
Wherein, this processor is also those the 3rd measured values in order to those the 3rd index of setting section, those the 3rd output valves of setting corresponding those the 3rd measured values are those standard values, produce those the 3rd output valves that do not correspond to those the 3rd measured values, one of them using this second output valve as those the 3rd index to be to obtain one the 4th output valve in those the 3rd output valves, and to set this second output valve be the 4th output valve.
14. image processing apparatus according to claim 11, it is characterized in that, this processor is also in order to calculate a residual sum of squares (RSS) between those first measured values and those standard values to obtain this error amount, or calculates a residual sum of squares (RSS) between those the 3rd measured values and those standard values to obtain this error amount.
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| TW101129559 | 2012-08-15 | ||
| TW101129559A TWI527428B (en) | 2012-08-15 | 2012-08-15 | Color calibration method and image processing device using the same |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104132897A (en) * | 2014-08-16 | 2014-11-05 | 西北农林科技大学 | Measuring method and device for nitrogen content of plant leaf on basis of handheld equipment |
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| US20030025925A1 (en) * | 2001-03-27 | 2003-02-06 | Global Graphics Software Limited | Establishing a reference printer state using a recursive tone scale matching |
| US6809837B1 (en) * | 1999-11-29 | 2004-10-26 | Xerox Corporation | On-line model prediction and calibration system for a dynamically varying color reproduction device |
| US20050018256A1 (en) * | 2003-07-25 | 2005-01-27 | Xerox Corporation | Method for improved characterization of single-pass bi-directional printers |
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- 2012-08-15 TW TW101129559A patent/TWI527428B/en not_active IP Right Cessation
- 2012-09-19 CN CN201210349245.6A patent/CN103595895A/en active Pending
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| US6809837B1 (en) * | 1999-11-29 | 2004-10-26 | Xerox Corporation | On-line model prediction and calibration system for a dynamically varying color reproduction device |
| US20030025925A1 (en) * | 2001-03-27 | 2003-02-06 | Global Graphics Software Limited | Establishing a reference printer state using a recursive tone scale matching |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN104132897A (en) * | 2014-08-16 | 2014-11-05 | 西北农林科技大学 | Measuring method and device for nitrogen content of plant leaf on basis of handheld equipment |
| CN104132897B (en) * | 2014-08-16 | 2018-11-06 | 西北农林科技大学 | A kind of nitrogenous measuring method of plant leaf blade based on handheld device and device |
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| Publication number | Publication date |
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| TW201408038A (en) | 2014-02-16 |
| TWI527428B (en) | 2016-03-21 |
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Application publication date: 20140219 |