Color sorting system and method

A method of real time image recognition of moving items having a plurality of color values for processing the items on the basis of color variations, comprising the following steps:

• constructing a look up table having memory locations addressable by the color values of items or portions thereof to be processed, where each addressable memory location is stored with a datum indicating an item or a portion thereof has acceptable or rejectable color values;
• capturing a color image of said moving items;
• normalizing said color values of said captured color image and using said normalized color values to address said look up table;
• expanding around a central color value a range of color values having said datum stored in corresponding look up table locations to compensate for any of system noise, a range of color variation, and optical variations;
• and
• reading out said datum from said look up table and determining which items or portions thereof are to be processed based on said acceptable or rejectable values as determined by said datum.

A method of analyzing and processing moving items corresponding to images represented by rows of pixels, each pixel having a value, said method comprising the following steps:

• capturing one of said images;
• normalizing each pixel value of said one of said captured images;
• designating pixels within said image, said pixels representing moving items, or portions thereof, and satisfying a criterion for processing said moving items;
• expanding around the value of said designated pixels a range of pixel values to compensate for any one of system noise, a range of color variation, or optical variations;
• storing a datum within a look up table at look up table locations addressed by said range of pixel values;
• and
• reading out said datum from said look up table locations and determining said processing of moving items or portions thereof, based on said criterion represented by said read out datum.

Apparatus for processing moving items in accordance with color, comprising:

• means for providing normalized color value signals corresponding to colors on the moving items,
• a first look up table having memory locations addressed by the normalized color value signals, each of said addressed locations having a stored datum indicating whether the colors to which the signals correspond are acceptable or not,
• a second look up table having addressable memory locations, each of which having accept/reject datum stored therein,
• logic means responsive to the output of the first look up table for directly addressing the memory locations of the second look up table, and
• means responsive to the addressed accept/reject datum from the second look up table for controlling the processing of the moving items.

A method of processing moving items in accordance with color, comprising the steps of:

• storing accept/reject datum at addressable locations in first and second look up tables to indicate whether address signals applied to the look up tables represent acceptable colors,
• providing normalized color value signals corresponding to colors at a plurality of sites on the moving items,
• addressing the first look up table with the normalized color value signals to provide said first look up table datum as output signals which indicate whether the colors at the sites on the moving items are acceptable,
• addressing the second look up table in accordance with a group of the output signals to provide said second look up table datum of processing signals which indicate whether the group of output signals is acceptable, and
• controlling the processing of the items in accordance with the processing signals.

In apparatus for sorting items in accordance with color on a moving conveyor belt:

• a. means for providing color value signals corresponding to colors at a plurality of sites on the conveyor belt;
• b. a look up table having memory locations addressed by the color value signals;
• c. means for loading the memory locations with data indicating whether the colors corresponding to the signals which address the locations are acceptable or not, said means comprising:
• (1) means for representing a sample color as a point in a three dimensional coordinate system in which three predetermined colors are plotted along first, second and third mutually perpendicular axes;
• (2) means for determining the spherical coordinates r,.phi.,.THETA. of the sample color, where r is the length of a vector extending from the origin to the point representing the sample color, .phi. is the angle between the first axis and the vector, and .THETA. is the angle between the second axis and the component of the vector in the plane of the second and third axes;
• (3) means for dithering the values of the spherical coordinates to define an ellipsoidal region in the coordinate system representing a range of colors centered generally about the sample color;
• and
• (4) means for storing data in the look up table at memory locations corresponding to the coordinates of points within the ellipsoidal region;
• and
• d. means responsive to data read from the look up table for controlling the course of the items on the conveyor belt.

In a method for sorting items in accordance with color on a moving conveyor belt, the steps of:

• a. providing color value signals corresponding to colors at a plurality of sites on the conveyor belt;
• b. addressing memory locations in a look up table with the color value signals;
• c. loading the memory locations with data indicating whether the colors corresponding to the signals which address the locations are acceptable or not, by the steps of:
• (1) representing a sample color as a point in a three dimensional coordinate system in which three predetermined colors are plotted along first, second and third mutually perpendicular axes;
• (2) determining the spherical coordinates r,.phi.,.THETA. of the sample color, where r is the length of a vector extending from the origin to the point representing the sample color, .phi. is the angle between the first axis and the vector, and .THETA. is the angle between the second axis and the component of the vector in the plane of the second and third axes;
• (3) dithering the values of the spherical coordinates to define an ellipsoidal region in the coordinate system representing a range of colors centered generally about the sample color;
• and
• (4) storing data in the look up table at memory locations corresponding to the coordinates of points within the ellipsoidal region;
• and
• d. controlling the course of the items on the conveyor belt in response to data read from the look up table.

Apparatus for processing moving items in accordance with color on said items, comprising:

• a. means for providing normalized color value signals corresponding to colors at a plurality of sites on an acceptable item and at a plurality of sites on an item to be rejected;
• b. means responsive to the normalized color value signals for accumulating the number of occurrences of individual colors in the acceptable item and accumulating the number of occurrences of individual colors in the item to be rejected;
• c. means for comparing the number of occurrences of the individual colors in the acceptable item with the number of occurrences of the colors in the item to be rejected;
• d. a look up table having addressable memory locations corresponding to the colors for storing accept/reject datum corresponding to the relative number of occurrences of the colors in the acceptable item and the number of occurrences of the colors in the item to be rejected;
• e. means for addressing the look up table with normalized color value signals corresponding to colors at a plurality of sites on the moving items to read the corresponding accept/reject datum out of the look up table;
• and
• f. means responsive to the accept/reject datum from the look up table for controlling the processing of the items.

A method of processing moving items in accordance with color, comprising the steps of:

• a. providing normalized color value signals corresponding to colors at a plurality of sites on an acceptable item and to colors at a plurality of sites on an item to be rejected;
• b. accumulating the number of occurrences of individual colors in the acceptable item and accumulating the number of occurrences of individual colors in the item to be rejected in accordance with the normalized color value signals;
• c. comparing the number of occurrences of the individual colors in the acceptable item with the number of occurrences of the individual colors in the item to be rejected;
• d. storing accept/reject datum corresponding to the relative number of occurrences of the colors in the acceptable item and the number of occurrences of the colors in the item to be rejected in a look up table having addressable memory locations corresponding to the colors;
• e. addressing the look up table with normalized color value signals corresponding to colors at a plurality of sites on the moving items to read the accept/reject datum out of the look up table;
• and
• f. controlling the processing of the moving items in accordance with the accept/reject datum from the look up table.