Sorting machine with digital error correction

Claim 2

Apparatus for sorting articles according to light-reflective properties, comprising: viewing means for sensing light energy reflected from an article to be sorted, said viewing means producing an electrical signal indicative of the light-reflective properties of the article; direct coupled amplifier means operatively coupled to said viewing means for amplifying said electrical signal; ejector means operatively coupled to said amplifier means for deflecting an article having predetermined light-reflective properties responsive to a corresponding amplified electrical signal; reference means for selectively providing a reference signal to said amplifier means; and normalizing means operatively coupled to said amplifier means for introducing an error correction signal to said amplifier means, said normalizing means including digital counter means for defining discrete stepwise output signals corresponding to the error correction signal, digital-to-analog converter means for introducing the output signals from the digital counter means to said amplifier means as corresponding analog signals; and control means for automatically redetermining said error correction in said digital counter means at predetermined time intervals.

Claim 3

Apparatus for sorting articles as recited in claim 1, wherein said reference means comprise a background selectively viewed by said viewing means to provide the reference signal.

Claim 4

Apparatus for sorting articles as recited in claim 1, wherein said normalizing means includes means for comparing the amplified signal output from said amplifier means responsive to said reference signal with a predetermined standard and to produce a control signal when said signal output is greater than said standard, and means for advancing said digital counter means responsive to said control signal.

Claim 5

Apparatus for sorting articles as recited in claim 1, including phase inverter means coupled between said amplifier means and said ejector means and providing an inverted amplifier output signal to said normalizing means.

Claim 6

Apparatus for sorting articles according to light-reflective properties, comprising: viewing means for sensing light energy reflected from an article to be sorted, said viewing means producing an electrical signal indicative of the light-reflective properties of the article; direct coupled amplifier means operatively coupled to said viewing means for ampifying said electrical signal; ejector means operatively coupled to said amplifier means for deflecting an article having predetermined light-reflective properties responsive to a corresponding amplified electrical signal; reference means for selectively providing a reference signal to said amplifier means; normalizing means operatively coupled to said amplifier means for introducing an error correction signal to said amplifier means, said normalizing means including digital counter means for defining discrete stepwise output signals corresponding to the error correction signal and digital-to-analog converter means for introducing the output signals from the digital counter means to said amplifier means as corresponding analog signals; and control means for clearing said viewing means of articles to be sorted, disabling said ejector means, providing said reference signal to said amplifier means, sensing the output of said amplifier means responsive to said reference signal, advancing said digital counter means until the output of said amplifier means is within a predetermined range of values, and resuming the sorting of said articles.

Claim 7

Apparatus for sorting articles according to light-reflective properties, comprising: viewing means for sensing light energy reflected from an article to be sorted, said viewing means producing an electrical signal indicative of the light-reflective properties of the article; direct coupled amplifier means operatively coupled to said viewing means for ampifying said electrical signal; ejector means operatively coupled to said amplifier means for deflecting an article having predetermined light-reflective properties responsive to a corresponding amplified electrical signal; reference means for selectively providing a reference signal to said amplifier means; normalizing means operatively coupled to said amplifier means for introducing an error correction signal to said amplifier means, said normalizing means including digital counter means for defining discrete stepwise output signals corresponding to the error correction signal and digital-to-analog converter means for introducing the output signals from the digital counter means to said amplifier means as corresponding analog signals; and control means for clearing said viewing means of articles to be sorted, disabling said ejector means, providing said reference signal to said amplifier means, sensing the output of said amplifier means responsive to said reference signal, advancing said digital counter means until the output of said amplifier means is within a predetermined range of values, and resuming the sorting of said articles.

Claim 8

IN A LIGHT-SENSITIVE SORTING MACHINE HAVING DIRECT COUPLED AMPLIFIER MEANS FOR AMPLIFYING ELECTRICAL SIGNALS INDICATIVE OF A LIGHT REFLECTIVE PROPERTY OF AN ARTICLE TO BE SORTED, THE IMPROVEMENT COMPRISING NORMALIZING MEANS OPERATIVELY COUPLED TO SAID AMPLIFIER MEANS FOR INTRODUCING AN ERROR CORRECTION THERETO, SAID NORMALIZING MEANS INCLUDING MEANS FOR SETTING SAID ERROR CORRECTION IN DIGITAL COUNTER MEANS, DIGITAL-TOANALOG CONVERTER MEANS OPERATIVELY COUPLED TO SAID DIGITAL COUNTER MEANS FOR INTRODUCING SAID ERROR CORRECTION TO SAID AMPLIFIER MEANS IN ANALOG FORMAT AND MEANS FOR REDETERMINING THE VALUE OF SAID ERROR CORRECTION AT SELECTED INTERVALS AND RESETTING SAID PREDETERMINED ERROR CORRECTION IN SAID NORMALIZING MEANS.

Claim 9

IN A LIGHT-SENSITIVE SORTING MACHINE HAVING DIRECT COUPLED AMPLIFIER MEANS FOR AMPLIFYING ELECTRICAL SIGNALS INDICATIVE OF A LIGHT REFLECTIVE PROPERTY OF AN ARTICLE TO BE SORTED, THE IMPROVEMENT COMPRISING NORMALIZING MEANS OPERATIVELY COUPLED TO SAID AMPLIFIER MEANS FOR INTRODUCING AN ERROR CORRECTION THERETO, SAID NORMALIZING MEANS INCLUDING MEANS FOR SETTING SAID ERROR CORRECTION IN DIGITAL COUNTER MEANS, DIGITAL-TOANALOG CONVERTER MEANS OPERATIVELY COUPLED TO SAID DIGITAL COUNTER MEANS FOR INTRODUCING SAID ERROR CORRECTION TO SAID AMPLIFIER MEANS IN ANALOG FORMAT AND MEANS FOR REDETERMINING THE VALUE OF SAID ERROR CORRECTION AT SELECTED INTERVALS AND RESETTING SAID PREDETERMINED ERROR CORRECTION IN SAID NORMALIZING MEANS.

Claim 10

Apparatus as recited in claim 6 wherein said normalizing means includes means for comparing the electrical signals output from said amplifier means with a predetermined value and means for advancing said digital counter means until said amplifier output responsive to a reference input signal is within the predetermined value.

Claim 11

Apparatus as recited in claim 6 wherein said normalizing means includes means for offsetting the error correction output by said digital-to-analog converter means to produce a desired range of outputs from said amplifier means when said digital counter means is stepped through a complete cycle.