Method and circuit for recognition of colors

In a method for preparing and recognizing colors on a colored image with the aid of a light source of known spectral composition, each color location corresponding to a color location in a color space, said color locations being defined by color component triplets representing the spatial coordinates of said color locations in said color space, said color space including at least one spatial color range being defined by at least one color location,

• the steps comprising:
• preparatory to color recognition
• selecting in said colors of said image a number of test points, each test point having a test point color;
• illuminating said image with said light source;
• photo-electrically measuring the color component triplets of the selected point colors;
• defining a certain identification symbol for each selected test point color;
• assigning the defined identification symbols to the color locations corresponding to respective selected test point colors;
• surrounding the color location of each test point color with selected color locations so as to form shells of successively increasing size around the color location of the color location of the corresponding test point color,
• calling-up said selected color locations shell by shell at successively increasing distances from the color location of the corresponding test point color,
• checking each called-up color location to determine whether an identification symbol has already been allotted thereto
• assigning the identification symbol allotted to a corresponding selected test point color to said called-up color location, provided no identification symbol has already been allotted to said called-up color location, all color locations bearing the same identification symbol thereby forming a color recognition region around the color locations of each corresponding selected test point color, each color recognition region representing a corresponding color range,
• thereafter performing the color recognition steps of:
• photo-electrically scanning said colored image so as to obtain the color component triplets corresponding to each image color,
• calling-up the color locations represented by said color component triplets and the identification symbols associated therewith, and
• reading out said identification symbols, whereby the image colors are identified.

In an apparatus preparing for, and recognizing colors on a colored image with the aid of a light source of known spectral composition to illuminate said colored image, each image color corresponding to a color location in a color space, said color locations being defined by a color component triplet representing the spatial coordinates of said color locations in said color space, selected image colors being denoted as test point colors and the image colors being identifiable by corresponding color identification symbols,

• comprising in combination:
• photo-electric transducer means for scanning said colored image and for measuring the color component triplets of the test point colors and of the image colors to be identified,
• analog-to-digital converter means postcoupled to said photo-electric transducer means for converting the measured analog component triplets into digitized color component triplets,
• color recognition memory means postcoupled to said analog-to-digital converter means, and including a plurality of first storage locations for storing said color identification symbols, said first storage locations being addressable by said digitized color component triplets,
• an identification symbol processor connected to said color recognition memory means, and including
• an input stage for the assignment of the identification symbols to the test point colors, respectively,
• a sample list being defined by the digitized color component triplets associated with the color locations of said test point colors, and the identification symbols assigned to the color locations of said test point colors, respectively,
• test point color memory means connected to said analog-to-digital converter means and to said input stage, and including a plurality of second storage locations for storing said sample list,
• address-control means connected to said color recognition memory means and to said test point color memory means for selecting addresses of said test point color memory means and of said color recognition memory means, and for calling up chosen color locations represented by said digitized color component triplets, and
• processing means connected to said test point color memory means, to said address control means, and to said color recognition means for determining the spatial distances separating called-up color locations represented by said called-up digitized color component triplets from said color locations of said test point colors represented by color component triplets contained in said sample list, respectively, and for determining the identification symbols to be assigned to the called-up digitized color component triplets, the so determined identification symbols being storable in said color recognition memory means and being capable of being called up therefrom.

An apparatus for recognizing colors on a colored image with the aid of a light source of known spectral composition to illuminate said colored image, each image color corresponding to a color location in a color space, said color locations being defined by a color component triplet representing the spatial coordinates of said color locations in said color space, selected image colors being denoted as test point colors and the image colors being identifiable by corresponding color identification symbols,

• comprising in combination:
• photo-electric transducer means for scanning said colored image and for measuring the color component triplets of the test point colors and of the image colors to be identified,
• analog-to-digital converter means postcoupled to said photo-electric transducer means for converting the measured analog component triplets into digitized color component triplets,
• color recognition memory means postcoupled to said analog-to-digital converter means, and including a plurality of first storage locations for storing said color identification symbols, said first storage locations being addressable by said digitized color component triplets, and
• an identification symbol processor connected to said color recognition memory means, including
• an input stage for the assignment of the identification symbols to the test point colors, respectively, a sample list being defined by the digitized color component triplets associated with the color locations of said test point colors and the identification symbols assigned to the color locations of said test point colors, respectively,
• test point color memory means connected to said analog-to-digital converter means and to said input stage, and including a plurality of second storage locations for storing said sample list,
• a shell being defined by surrounding the color location of each test point with selected color locations so as to form a multiplicity of shells of successively increasing size around the corresponding test point color, each shell having a plurality of shell coordinates, the shell coordinates of all shells defining a shell list,
• shell memory means including a plurality of third storage locations for storing said shell list,
• address-control means connected to said test point color memory means and to said shell memory means for addressing said test point color memory means and said shell memory means,
• processing means connected to said test point color memory means, to said shell memory means and to said color recognition memory means for determining selected addresses from said sample list and from said shell list for addressing said color recognition memory means by said selected addresses, and for determining the identification symbols to be assigned to the called-up addresses of said color recognition memory means, and
• switching means for checking whether said first storage locations of said color recognition memory means are free from any identification symbols already stored therein.