JP3206781B2 - Color conversion processor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color conversion processing apparatus for performing color adjustment of a color image by a user's specification and color correction in accordance with the color reproduction characteristics of an input / output device.

[0002]

2. Description of the Related Art For example, a conventional color conversion processing device used in a color printer has a configuration as shown in FIG. In the color conversion processing device 5 shown in FIG. 8, the color signals R, G, and B corresponding to red, green, and blue are converted by the matrix processing unit 51 into color material signals cmy corresponding to cyan, magenta, and yellow. Further, each of the color material signals cmy is converted to an LUT (look-up ta).
ble) The color material signals C, M, and Y are supplied to a processing unit and supplied to an output device (not shown). In the color conversion processing device 5 shown in FIG. 8, after performing color correction by matrix processing on a color image according to the color material of the output device,
Correction suitable for the gradation of the output device is performed by LUT processing.

As another conventional example, Adobe S
pages Description Language PostScript (Adobe System) by systems Incorporated
There is a method of designating the procedure of the color conversion process using a language called msIncorporated (registered trademark). For example, according to the “Page Description Language PostScript (registered trademark) Reference Manual Second Edition” issued by ASCII Corporation, color conversion is represented by a combination of matrix processing and procedural processing in two stages, and the color conversion characteristics are described on the page. It is defined by the description language PostScript. That is, as shown in FIG. 9, the set of the procedure processing unit 61 and the matrix processing unit 62 is the first stage, the set of the procedure processing unit 63 and the matrix processing unit 64 is the second stage, It is assumed that the color conversion processing device 6 is configured by combining the first stage and the second stage. The procedure processing units 61 and 63 are, for example, LUT processing units.

In the color conversion processing device 6 shown in FIG. 9, signals A, B, and C of an arbitrary color system are subjected to, for example, LUT processing in a procedure
After being converted into _A (A), D _B (B), and D _C (C), the matrix processing unit 62 converts the signals L, M,
Converted to N. The signal signals L, M and N are subjected to, for example, an LUT process in a procedure
After being converted into _L (L), D _M (M), and D _N (N), the matrix processing unit 64 further converts the signals into XYZ color system signals X, Y, and Z.

[0005]

However, in the above-mentioned conventional technique, the processing unit of the color conversion processing, that is,
Although parameters such as matrix processing, LUT processing, and procedural processing can be changed, the number and order of processing units are fixed. For this reason, there is a disadvantage that complicated color conversion cannot be performed.

For example, FIG. 10 shows NTSC RγGγBγ
FIG. 2 is a block diagram illustrating a color conversion processing device for converting a signal into a YCbCr signal, performing color adjustment by matrix processing, and converting the signal into a CIE1976L ^* a ^* b ^* signal. In the device shown in FIG. 10, the NTSC RγGγBγ signal is converted into a YCbCr signal by a matrix processing unit 701, and color adjustment is performed by a matrix processing unit 702.
The NTSC RγG is again processed by the matrix processing unit 702.
It is converted to a γBγ signal. As described above, by temporarily converting to YCbCr signals and performing color adjustment, Y, Cb, Cr
Can be adjusted independently, so that, for example, hue and saturation can be easily changed without changing brightness. The NTSC RγGγBγ signal after color adjustment is output to the inverse γ processing unit 7.
At 04, the signal is subjected to inverse gamma processing to become an NTSC RGB intensity signal. The NTSC RGB intensity signal is converted into XYZ signals by matrix processing unit 705, X / X _O in the matrix processing unit 706, Y / Y _O, performs a calculation of Z / Z _O, function LUT processor 707 f (X /
X _O ), f (Y / Y _O ), and f (Z / Z _O ) are obtained, and L ^* , a ^* , and b ^* are obtained by the matrix processing unit 708. The matrix processing unit 706, the LUT processing unit 707, and the matrix processing unit 708 convert an XYX color system into an L ^* a ^* b ^* color system based on a well-known conversion formula.

When the input / output color space is fixed in advance as in a conventional stand-alone copying machine or the like, it does not matter if the number and order of processing units are fixed. Since the devices connected to the network are unique to various color spaces, it is becoming an important issue to cope with complicated color conversion in order to enable mutual conversion.

Further, even if the number and order of the processing units are variable to cope with complicated color conversion, there is a disadvantage that the complicated color conversion as shown in FIG. 10 takes a long processing time.

Accordingly, an object of the present invention is to enable complicated color conversion and to shorten the processing time.

[0010]

As shown in FIG. 1, according to the present invention, a processing unit constituting a color conversion is represented by processing unit type data indicating a type of a processing unit and a processing parameter. A plurality of processing unit connection means 11; a plurality of processing units connected by the processing unit connection means 11; a synthesis determination means 21 for determining whether or not the plurality of processing units can be synthesized based on the processing unit type data; 2
(1) processing unit synthesizing means (22) for synthesizing a plurality of processing units based on the judgment of (1);
3, a non-conversion determining unit 31 for determining whether the processing unit is a non-conversion process based on the processing unit type data of the processing unit synthesized by the processing unit synthesizing unit 22 and the processing parameter, A processing unit deletion unit 32 for deleting a processing unit based on the determination of the determination unit 31, and combining and deleting processing units as much as possible based on the determination of the combination determination unit 21 and the non-conversion determination unit 31. It has a control means 33 for repeating.

[0011]

Since the processing units can be freely connected in number and order by the processing unit connection means, complicated color conversion can be expressed.

Further, the number of processing units can be reduced by the processing unit synthesizing means 22, and unnecessary processing units can be deleted by the processing unit deleting means 32, so that unnecessary processing can be omitted, thereby shortening the processing time. Can be done.

[0013]

An embodiment of the present invention will be described with reference to FIG.

The color conversion processing apparatus shown in FIG. 2 is roughly divided into a processing unit initialization block 1 for initializing a connection state of each processing unit according to a color conversion method, and a processing unit that can be combined. It comprises a combining block 2 for combining, a non-conversion deletion block 3 for deleting a processing unit that does not perform conversion, and a processing unit sequence storage device 4 for storing a connection state of each processing unit.

Before performing the color conversion, an initialization command is sent to the processing unit initialization block 1 to connect the color conversion processing units so that a predetermined color conversion is performed. The processing unit connection means 11 provided in the processing unit initialization block 1 converts the designated color conversion, for example, from the NTSC RGBγ signal of FIG. 10 to the YCbCr signal, performs color adjustment by matrix processing, and performs the CIE1976L ^* a ^* b ^* signal. The color conversion processing unit is connected so as to represent the conversion to, and this is stored in the processing unit column storage means 41 of the processing unit column storage device 4. Information about each processing unit, that is, the processing unit type data and the processing parameter are stored in the processing unit sequence storage unit 41 in the order of execution in the processing unit. For each processing unit, a combining / deleting process is performed as described below, and the processing unit type data and the processing parameter are changed according to the result of the combining / deleting process. Further, the arrangement position in the processing unit sequence storage means 41 is also changed. In addition, the address of the first processing unit of the connected processing unit sequence is set in the data of the target processing unit designating unit 42 that indicates the processing unit to be subjected to the processing unit rearrangement, for example, in a pointer that indicates the address of the target processing unit. The connected processing unit sequence at this time is shown in [Step 1] of FIG. Processing unit type data is described above each processing unit in the figure, and processing parameters are described below. For example, the processing unit type data of the processing unit 701 is “matrix 3 × 3”, and the processing parameters are matrix coefficients of a11 to a33. In the figure, reference numeral 709 denotes a dummy processing unit for indicating the end of the processing unit sequence, which has only the processing unit type data “end”, has no processing parameter, and is combined with another processing unit and is not converted. Cannot be deleted, and is not used for actual color conversion processing.

In this embodiment, matrix processing, inverse γ conversion processing, and LUT processing are taken as examples of processing units. However, the present invention is not limited to this, and other processing units can be used.

Next, the work data initialization means 12 of the processing unit initialization block 1 converts the data held in the synthesis result storage means 24 and the non-conversion deletion result storage means 34 into
For example, it is cleared to 0.

Next, control is transferred to the synthesis block 2. The combination control unit 23 calls the combination determination unit 21. The combining determination unit 21 determines whether the target processing unit pointed to by the target processing unit designating unit 42 stored in the processing unit storage unit 41 and a processing unit continuous with the target processing unit can be combined.
The processing unit type data of the processing unit is used for the determination. For example, since the processing units 701 and 702 in FIG. 3 are both a matrix of “3 × 3” and “3 × 3 + constant” in the matrix processing, both are processed into one “3” as in the following equation.
It is determined that the combination can be performed with the matrix processing unit 710 of the “× 3 + constant” type, and the combination determination unit 21 returns the determination result.

[0019]

(Equation 1) Here, a11 to a33 are matrix coefficients of the matrix processing unit 701 b11 to b33 are matrix coefficients of the matrix processing unit 702 c1 to c3 are matrix processing units 702 and 710
H11 to h33 are matrix coefficients of the matrix processing unit 710, and x1 to x3 are input variables.

Other possible conditions for synthesis include, for example, m
Matrix with row n columns (m × n) and l rows and m columns (l × m)
, The LUT processing and the γ conversion processing are continuous. Further, the present invention is not limited to the continuation of the same kind, and as described in JP-A-1-108867, when the LUT and the matrix are continuous, they can be combined to represent the matrix processing in the LUT format. is there.

When the synthesizing determination means 21 returns that synthesizable, the synthesizing control means 23 instructs the processing unit synthesizing means 22 to perform synthesizing. The processing unit synthesizing means 22 is a processing unit 7 shown in FIG.
The processing parameters of 01 and 702 are combined, created as a new processing unit 710 (FIG. 4 [Step 2]), and unnecessary processing units 701 and 702 are deleted (FIG. 4 [Step 3]). The processing unit 710 is inserted and connected (FIG. 4 [Step 4]), and the processing unit sequence storage unit 41 is connected.
Update the processing column held by. At this time, the data of the target processing unit designating means 42 is also updated so as to indicate the combined processing unit 710. Then, a predetermined value, for example, 1 is set in the synthesis result storage means 24 in order to store that the synthesis has been performed. This completes one synthesis process (FIG. 5 [Step 5]).

The combining control unit 23 until the combining determination unit 21 returns a combination impossible or the target processing unit designating unit 42 points to the end processing unit 709 of the processing unit sequence.
Repeatedly executes the above synthesis (FIG. 6 [Step 6]). Next, the control is shifted to the non-conversion deletion block 3, and the non-conversion deletion control means 331 calls the non-conversion determination means 31. The non-conversion determination unit 31 determines whether the target processing unit processing unit pointed to by the target processing unit designating unit 42 stored in the processing unit sequence storage device 4 can be deleted in the non-conversion unit. For the determination, both the processing unit type data of the target processing unit and the processing parameter are used. For example, the previously combined processing unit 7
Consider 10 decisions. Since the processing unit 710 is a “3 × 3 + constant” type of matrix processing, the non-conversion determination unit 31 determines that the processing unit is a non-conversion processing unit if the matrix parameter and the constant term as processing parameters satisfy the following conditions.

H _ij = 1, i = j h _ij = 0, i ≠ j c _i = 0 Other non-conversion processing determination conditions of the processing unit type include:
For example, in the case of 3 × 3 matrix processing, whether the matrix is a unit matrix, in the case of LUT processing, whether the input and output values of the LUT are the same, and in the case of γ correction or inverse γ correction, γ = 1
And so on.

If the non-conversion judgment means 31 returns a judgment result indicating that deletion is possible, the no-conversion deletion control means 331
Instructs the processing unit deletion unit 32 to delete the non-conversion processing unit. The processing unit deletion unit 32 deletes the non-conversion processing unit, reconnects the processing units before and after it, and updates the processing sequence stored in the processing unit sequence storage unit 41. At this time,
The data of the target processing unit designating unit 42 is also updated so as to point to the next processing unit after the deleted processing unit. And
In order to store the fact that the deletion has been performed, the data is set to, for example, 1 in the no-conversion deletion result storage means 34. This completes one non-conversion deletion process.

The non-conversion deletion control unit 331 executes the non-conversion deletion processing until the non-conversion determination unit 31 returns a deletion impossible or the target processing unit designating unit 42 indicates the end processing unit 709 of the processing unit sequence. Is repeatedly executed.

In the next repetition control means 332, the data of the target processing unit designating means 42
It is checked whether it points to the processing unit 09, and if it does not point to the end, the target processing unit designating unit 42 is changed to point to the next processing unit currently pointing, and control is transferred to the combining control unit 23, and the processing unit combining And the conversion-free processing unit deletion is repeated.

On the other hand, if the target processing unit designating means 42 points to the end, it is checked whether data is set in the combined result storing means 24 and the non-conversion deletion result storing means 34. If data is set in either one of them, it is determined that the processing unit has been rearranged, the control is transferred to the determination result initializing means 12, and the processing unit sequence is synthesized / deleted again. This is because the rearrangement of the entire processing unit sequence is performed again because two originally non-consecutive processing units may be connected and combined in some cases due to the rearrangement of the processing units.

If no data has been set in both, it is determined that further processing unit reordering is not possible, and the reordering of the processing unit sequence is terminated (FIG. 7 [Step 7]). Then, since the terminal processing unit 709 of the processing unit sequence stored in the processing unit sequence storage unit 41 is unnecessary, the terminal processing unit 709 is deleted, and then the end of initialization is output to end the initialization of the color conversion process. Thereafter, the color conversion processing of the input image is started.

[0029]

As described above, according to the present invention, a processing unit sequence in which color conversion processing units are freely connected is formed, and the synthesis and deletion of the processing units therein are repeatedly performed to simplify the color conversion processing. This makes it possible to carry out complicated color conversion processing, and the processing time can be shortened.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an outline of the present invention.

FIG. 2 is a block diagram showing an embodiment of the present invention.

FIG. 3 is a diagram illustrating an example of a color conversion processing unit sequence.

FIG. 4 is an explanatory diagram showing a procedure of combining and deleting processing units.

FIG. 5 is an explanatory diagram showing a procedure of combining and deleting processing units following FIG. 4;

FIG. 6 is an explanatory diagram showing a procedure of combining and deleting processing units following FIG. 5;

FIG. 7 is an explanatory diagram showing a procedure of combining and deleting processing units following FIG. 6;

FIG. 8 is a block diagram showing a first conventional example.

FIG. 9 is a block diagram showing a second conventional example.

FIG. 10 is a diagram illustrating an example of a color conversion process.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Processing unit initialization block, 11 ... Processing unit connection means, 12 ... Work data initialization means, 2 ... Synthesis block, 21 ... Synthesis determination means, 22 ... Processing unit synthesis means, 2
DESCRIPTION OF SYMBOLS 3 ... Synthesis control means, 24 ... Synthesis result storage means, 3 ... Non-conversion deletion block, 31 ... Non-conversion determination means, 32 ... Processing unit deletion means, 33 ... Synthesis deletion control means, 331 ... Non-conversion deletion control means, 332 ... repetition control means, 34 ... non-conversion deletion result storage means, 4 ... processing unit sequence storage device, 41 ...
Processing unit sequence storage means, 42... Target processing unit designating means, 5
... color conversion processing in the first conventional example, 6 ... color conversion processing in the second conventional example, 7 ... example of color conversion processing, 700 ... part of the color conversion processing, 701 to 703, 705, 706, 7
08, 710 to 712: Matrix processing unit, 704
... Inverse γ conversion processing unit, 707 LUT processing unit, 709
… Terminal processing unit

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H04N 1/46-1/64 G06T 1/00 510

Claims (4)

(57) [Claims] 1. A processing unit connection unit for connecting a plurality of processing units each including processing unit type data representing a type of a processing unit constituting color conversion and a processing parameter; and a plurality of processes connected by the processing unit connection unit. A combination determining unit that determines whether a unit can be combined based on the processing unit type data; and a processing unit combining unit that combines a plurality of processing units based on the determination of the combination determining unit. Color conversion processing device. 2. The color conversion processing device according to claim 1, further comprising a combination control unit that repeats the combination of the processing units as much as possible based on the determination by the combination determination unit. 3. A non-conversion determining unit for determining whether the processing unit is a non-conversion process based on the processing unit type data of the processing unit synthesized by the processing unit synthesizing unit and the processing parameter; 2. The color conversion processing device according to claim 1, further comprising a processing unit deleting unit that deletes the processing unit based on the determination by the determining unit. 4. The apparatus according to claim 3, further comprising a composition / deletion control means for repeating composition and deletion of processing units as much as possible based on the judgment of the composition judgment means and the judgment of the no-conversion judgment means. Color conversion processor.