Method and apparatus for partial recorrection of color recognition spaces in printing techniques

Claim 2

Method for partial follow-up correction of color recognition spaces in color recognition, in which identification symbols in the colors to be recognized are assigned to the color locations or, respectively, the color component triads of trichromatically measured sample points and in which, for the formation of color recognition spaces around the sample color locations, identification symbols for the corresponding color locations are determined from the identification symbols of the sample color locations, whereby color locations with the same identification symbol respectively form one color recognition space, characterized in that at least one additional sample color location or, respectively, its color component triad is marked at a color recognition space in the spatial environment of the subsequent boundary correction and, if need be, a different identification symbol is assigned thereto, in that the previously accomplished allocation of identification symbols is negated for the color locations lying around the additional sample color location within a spatial cancel area; and in that each color location of the cancel area is newly occupied with an identification symbol determined from the identification symbols of the sample color locations.

Claim 3

Method according to claim 1 characterized in that the additional sample color location is marked by means of trichromatic measurement of a further sample point.

Claim 4

Method according to claim 1 characterized in that the cancel area is formed of cups around the additional sample color location in that the color locations lying within the cup are called in cup-by-cup with in-creasing distances from the additional sample color location up to the boundaries of the cancel area and the allocated identification symbols are cancelled.

Claim 5

Method according to claim 3, characterized in that the cups are designed as spherical cups and the cancel areas have a spherical shape.

Claim 6

Method according to claim 3 characterized in that the formation of the cancel area is terminated when it becomes tangential to a neighboring cancel area.

Claim 7

Method according to claim 1, characterized in that color locat-ions are called in for the formation of the cancel area and are checked as to their association with the cancel area, and in that the allocated identi-fication symbols are cancelled in case the called-in color locations lie within the boundaries of the cancel area.

Claim 8

Method according to claim 6, characterized in that the bound-aries of the cancel area are prescribed.

Claim 9

Method according to claim 6, characterized in that the bound-aries of the cancel area are calculated.

Claim 10

Method according to claim 7 or 8 characterized in that the cups are designed as spherical cups, the cancel areas have a spherical shape and the boundaries of the spherical cancel area are fixed by means of the radius.

Claim 11

Method according to claim 8 characterized in that the radius of the cancel area is determined from the spatial distance of the additional sample color location from that sample location lying closest to it which has an identification symbol which differs with respect to the additional sample color location.

Claim 12

Method according to claim 8 characterized in that the radius of the cancel area is determined from the spatial distance of the additional sample color location from that color location whose identification symbol or, respectively, association with a color recognition space is not to be changed in the subsequent boundary direction.

Claim 13

Method according to claim 11, characterized in that the appertaining color location is marked by means of trichromatic measurement of the color components in the colors to be recognized.

Claim 14

Method according to claim 6 characterized in that the respective spatial distance between the additional sample color location and a called-in color location is determined, and in that the association of the called in color location to the cancel area is identified by means of comparison of the distance to the radius of the cancel area.

Claim 15

Method according to claim 1, characterized in that, for re-occupying the cancel area, each color location of the cancel area has the identification symbol of that sample color location assigned to it which lies at the greatest spatial proximity to it.

Claim 16

Method according to claim 14, characterized in that, for re-occupying the cancel area, respectively equidistant cups are placed around the individual sample color locations and the color locations within said cups are checked as to their non-occupation with identification symbols, and in that the identification symbols of the respectively central sample color locations are assigned to the non-occupied color locations.

Claim 17

Method according to claim 14, characterized in that, for the re-occupation of the cancel area, the color locations are called in cup-by-cup with increasing intervals from the additional sample color location, in that the respective spatial distances of a called-in color location to all sample color locations are determined and compared to one another, and in that the called-in color locations respectively have the identification symbol of the sample color location assigned to them which lies at the closest spatial proximity.

Claim 18

Method according to claim 14, characterized in that the color locations are called in for the re-occupation of the cancel area and are checked for their non-occupation with identification symbols, in that, in case of a non-occupation, the respective spatial dis-tances of a called-in color location to all sample color locations are identified and compared to one another, and in that the identification symbol of the sample color location lying at the close spatial proximity is assigned to the non-occupied color locations.

Claim 19

Method according to claim 3, characterized in that the cup coordinates (xsm, ysm and zsm of all color locations participating in the formation of the mth spherical cup derive from the number of whole numbers which suffice the spherical equation M = r2 = x2sm + y2sm + z2sm

Claim 20

Method according to claim 18, characterized in that the cup-coordinates (xsm, ysm, zsm) of a locations participating in the formation of the mth spherical shell are determined by means of permutation and operational sign reversal from at least one ordered coordinate triad which fulfills the spherical equation with the radius m.

Claim 21

Method according to claims 18 or 19, characterized in that the color coordinates (xi, yi, zi) of the color locations to be called in around a sample color location are calculated as a cup center front the cup coordinates (xsm, ysm, zsm) and the color coordinates (xpn, ypn, zpn) of the appertaining sample color location according to the equations: xi = xpn + xsm yi = ypn + ysm zi = zpn + zsm

Claim 22

Method according to claim 1, characterized in that the spatial distances (d) between a first color location with the color c-ordinates (x1, y1, z1) and a second color location with the color coordinates (x2, y2, z2) are calculated according to the vectorial equation: d = (x2 - x1)2 + (y2 - y1) + (z2 - z1)

Claim 23

Method according to claim 1, characterized in that memory locations of a first memory (color recognition storage) are assigned to the color locations, said memory locations being addressable by means of the digitized color coordinates of the color locations, and in that the identification symbols of the color locations are deposited at the allocated memory locations.

Claim 24

Method according to claim 22, characterized in that the color coordinates are digitized with different resolution.

Claim 25

Method according to claim 22, characterized in that a sample list formed from the color coordinate triads of the sample points and the allocated identification symbols and a list of additional samples formed from the color coordinate triads of the additionally measured sample points and the allocated identification symbols are deposited in a second memory (sample memory) and the cup coordinates of the individual cups being likewise deposited under continuous addresses as a cup list in a third memory (cup memory), and in that the addresses of the second and third memory are called in and the color coordinates and, respectively, addresses of the first memory are determined from the sample list and/or the list of additional samples as well as from the cup list.

Claim 26

25, Method according to claim 22, characterized in that the addresses of the first memory are continuously called in and are checked as to their association to the address area which corresponds to the cancel area.

Claim 27

Method according to one of the claims 1, 2 and 3 characterized in that the color coordinates correspond to the trichromatic chromatometry value signals (R, G, B).

Claim 28

Method according to one of the claims 1, 2 and 3 characterized in that the color coordinates correspond to the chrominance signals (x,y) and to the brightness signal (z), and in that the chrominance signals (x, y) and the brightness signal (z) are gained by means of coordinate transformation of the RGB color space into the chrominance/luminance color space.

Claim 29

Method according to one of the claims 1, 2 and 3 characterized in that the color coordinates correspond to the cylinder color coordinates (saturation, tint, luminance), and in that the cylinder color coordinates (saturation, tint, luminance) are gained by means of a coordinate transformation of the chrominance/luminance color space into the saturation/tint/brightness color space.

Claim 30

Method according to one of the claims 1, 2 and 3 characterized in that the identification symbols are displayed.

Claim 31

Method according to claim 1 characterized in that sectional planes (chrominance planes) through the color space or, respectively, through the color recognition spaces are displayed on a monitor.

Claim 32

Method according to claim 30, characterized in that the identification symbols deposited in the first memory are loaded into an image repetition memory, in that the identification symbols of one memory level (z level) are cyclically read out, in that a triad of color signals is allocated to each identification symbol, and in that the color signals drive a color monitor.

Claim 33

Method according to claim 30 or 31, characterized in that the sectional planes of the color recognition spaces displayed on the color monitor are re-adjusted with the assistance of a cursor by means of cor-responding substitution of identification symbols.

Claim 34

Circuit arrangement for executing the method according to claim 1, comprising a light source of a known spectral composition for illumina-ting the colored surfaces to be investigated, comprising three opto-electronic transducers for measuring the color coordinate of sample points in the surfaces, and comprising a color recognition storage for the accep-tance of identification symbols, said color identification storage being connected via analog-to-digital converters to the opto-electronic transducer and being addressable by means of digitized color coordinates, characterized by an input stage for the allocation of identification symbols, a sample memory connected to the input stage and to the analog-to-digital conver-ters, said sample memory being provided for the deposit of sample lists formed from the color coordinates of the measured sample point and the allocated identification symbols, a cup memory for the deposit of the cup coordinates in the form of a cup list, an arithmetic circuit for calculating and calling in the addresses of the color recognition storage and for determining the appertaining identification symbols, said arithmetic cir-cuit being connected to the sample memory, the cup memory, and the color recognition storage, an address control unit for calling in the sample lists and the cup lists, said address control unit being connected to the sample memory, the cup memory and the arithmetic circuit, and a circuit stage for checking the called-in memory locations as to their occupation with identification symbols.

Claim 35

Circuit arrangement according to claim 33, characterized in that a display unit for the identification symbols is postconnected to the color recognition storage.

Claim 36

Circuit arrangement according to claim 34, characterized by an image repetition memory for the identification symbols connected to the color recognition storage, a color monitor for the display of sectional surfaces through the color space, said color monitor being drivable by the color signals by a color generator connected to the image repetition mem-ory and the color monitor, said color generator allocating a freely selectable triad of color signals to each read-out identification symbol for the drive of the color monitor, and by a control circuit for calling in the memory addresses and for the substitution of identification symbols, said control circuit being connected to the image repetition memory.