Circuitry for sorting fruit according to color

Abstract

A circuit for detecting the color of a fruit on a conveyor by measuring the light reflected from the surface of the fruit at a viewing station and for providing an appropriate discharge signal so that the fruit will be discharged to a particular discharge location at a position spaced downstream from the viewing station. The circuit includes .[.means .]. .Iadd.a light collecting device and filters .Iaddend.for separately measuring the amount of light reflected within two distinct bands of wavelengths of light, continuously computing the ratio of the same to derive an analog ratio signal, and comparing the ratio signal with a plurality of predetermined ratio signals in order to obtain said appropriate discharge signal. A memory circuit is included so that discharge signals for a plurality of fruit can be stored for an indeterminate period of time before any one of such fruit is directed to its discharge location.

What is claimed is: 
     
       1. In an apparatus for sorting fruit according to the color thereof, circuitry comprising detection means for producing a pair of continuous light reflection signals indicative of the amount of light reflected by a fruit within two different bands of wavelengths of light, means for continuously electrically dividing said signals to provide an analog ratio signal which is proportional to the ratio of said light reflection signals, a plurality of comparators each of which is arranged to simultaneously compare said ratio signal with a predetermined fixed ratio signal, and means operatively connected to each of said comparators for providing a discharge signal representative of a decision to direct said fruit to a particular discharge location. 
     
     
       2. In an apparatus for sorting fruit as set forth in claim 1, means for storing said discharge signal until such time as said fruit is in position to be directed to said particular discharge location, and means responsive to said last named means for providing a signal to operate a discharge mechanism when said fruit is in a position to be directed to said discharge location. 
     
     
       3. In an apparatus for sorting fruit as set forth in claim 2 wherein said means for storing said discharge signal comprises a primary memory means and a reserve memory means, means operative to normally transfer said discharge signal to said primary memory means but being operative to transfer a discharge signal to said reserve memory means if a signal is already present in said primary memory means, and means operative to transfer any discharge signal in said reserve memory means to said primary memory means each time that a fruit is moved to its discharge location whereby two fruit may be analyzed by said detection means before the discharge of either fruit to its discharge location. 
     
     
       4. In an apparatus for sorting fruit as set forth in claim 1 wherein said bands of wavelengths of light are distinct with no overlapping thereof. 
     
     
       5. In an apparatus for sorting fruit as set forth in claim 4 wherein one of said bands is comprised of wavelengths of light of greater than about 750 nanometers and wherein the other of said bands is comprised of wavelengths of light of between about 560 nanometers and about 630 nanometers. 
     
     
       6. In an apparatus for sorting fruit as set forth in claim 1 wherein each of said comparators is arranged to provide an output signal if said analog ratio signal is greater than the fixed ratio signal associated with said comparator, and a logic circuit for simultaneously analyzing the output signals of each of said comparators in order to provide said discharge signal. 
     
     
       7. In an apparatus for sorting fruit as set forth in claim 6 including gating means connected between each of said comparators and said logic circuit, and means for sensing the presence of said fruit at a location wherein said detection means will receive the reflected light from said fruit, said sensing means being operative to open and close said gating means to permit signals to be passed to said logic circuit only when a fruit is in position to reflect light to said detection means. 
     
     
       8. In an apparatus for sorting fruit according to the color thereof, circuitry comprising detection means for producing a pair of continuous light reflection signals indicative of the amount of light reflected by a fruit within two different bands of wavelengths of light, means for continuously electrically dividing said signals to provide an analog ratio signal which is proportional to the ratio of said light reflection signals, means for comparing said ratio signal with a plurality of signals each of which are equal to a different predetermined fixed ratio signal, means operatively connected to said comparing means for providing a discharge signal representative of a decision to direct said fruit to a particular discharge location, and means for rendering said means for providing a discharge signal operative during the period of time which is required for said fruit to be conveyed past said detection means, said means for providing a discharge signal being arranged to provide said discharge signal in accordance with the peak value of said analog ratio signal during the time that said fruit is conveyed past said detection means. 
     
     
       9. In an apparatus for sorting fruit as set forth in claim 8 wherein said comparing means comprises a plurality of comparators each of which provide an output only if the analog ratio signal which is applied to the input thereof is greater than the predetermined fixed ratio signal applied to the input of the comparator. 
     
     
       10. In an apparatus for sorting fruit according to claim 9 wherein said means for providing a discharge signal includes a plurality of bistable elements each of which are connected to the output of one of said comparators, each of said bistable elements being arranged to change state upon the reception of an output signal from its associated comparator. 
     
     
       11. In an apparatus for sorting fruit according to claim 10 wherein each of said bistable elements comprises a flip-flop circuit, and a logic circuit connected to the outputs of said flip-flop circuits for simultaneously analyzing said outputs of said flip-flop circuits in order to provide said discharge signal. .[.12. In an apparatus for sorting fruit according to the color thereof, circuitry comprising first fruit sensing means for detecting the presence of a fruit at a viewing station, means for receiving the light reflected from said fruit and for providing a discharge signal in accordanc with the color of said fruit and representative of a decision to direct said fruit to a particular discharge location, said means for providing said discharge signal being activated by said first sensing means, second sensing means for detecting the presence of said fruit at a discharge station which is spaced downstream in the direction of movement of said fruit from said viewing station, discharge circuit means operatively connected to receive said discharge signal when activated by said second sensing means so as to cause said fruit to be directed to the correct discharge location in accordance with the color thereof, and means for storing said discharge signal for an indeterminate period of time prior to activation of said discharge circuit means, said signal storing means having a capacity to store a plurality of discharge signals at any given time whereby a plurality of fruit may be viewed before discharge of any one of such fruit to its discharge location..]. .[.13. In an apparatus for sorting fruit as set forth in claim 12 wherein said means for storing said discharge signal comprises a primary memory means and a reserve memory means, means operative to normally tranfer said discharge signal to said primary memory means but being operative to transfer a discharge signal to said reserve memory means if a signal is already present in said primary memory means, and means operative to transfer any discharge signal in said reserve memory means to said primary memory means each time a fruit is moved to its discharge location..]. .[.14. In an apparatus for sorting fruit as set forth in claim 12 including means operatively connected to said first sensing means for causing the transfer of a dischrge signal into said signed storing means when the period of detection of a fruit by said first fruit sensing means ceases..].