Remote operation of optical system

• US 4,862,397 A
• Filed: 08/27/1987
• Issued: 08/29/1989
• Est. Priority Date: 01/03/1983
• Status: Expired due to Term

• Current Assignee: LMI Technologies Inc.
• Original Assignee: Diffracto, Ltd. (LMI Technologies Inc.)
• Inventors: Pryor, Timothy R.
• Primary Examiner(s): Lall, Parshotam S.
• Assistant Examiner(s): Melnick, S. A.
• Application Number:
  US07/089,836
• Time in Patent Office: 733 Days
• Field of Search: 364/571.05, 364/571.01, 364/573, 364/551.01, 364/552, 364/525, 250/204, 250/205, 340/793, 358/107
• US Class Current: 250/205
• CPC Class Codes: B25J 9/1697 Vision controlled systems
• CPC Class Codes: G05B 19/4063 Monitoring general control system G05B19/4062 takes precedence
• CPC Class Codes: G05B 2219/37151 Handling encoder signal, compensation for light variation, stray light
• CPC Class Codes: G06K 7/10851 Circuits for pulse shaping, amplifying, eliminating noise signals, checking the function of the sensing device basic electronic circuitry H03
• CPC Class Codes: G06V 10/10 Image acquisition document image scanning and transmission H04N1/00; control of digital cameras H04N23/60
• CPC Class Codes: H04N 23/75 by influencing optical camera components

Abstract

A method and apparatus for controlling a detector array based optical system using reflected or transmitted light for machine vision is disclosed. The light characteristic such as power (intensity) or distribution of power received by said optical system is detected and an electrical signal indicative of the characteristic is transmitted to a remote control system. The control system then adjusts a light power related variable of the optical system when the received light characteristic signal is deficient. A method and apparatus for linearizing the output of a diode array is also disclosed. An element correction array is set up in a microprocessor and an encoding device providing precise edge movement data is moved past the elements of the diode array so that the data from the encoder and from the diode array can be compared and the difference inputted as offset values for the corresponding positions of the elements in the correction array. Thereafter, during operation, the offset values are added to the diode array element reading to obtain a corrected diode array output which is substantially linear.

Claims

1. A control system for a detector array based optical system used for machine vision which optical system has a detector array which receives light from a plurality of succeedingly presented objects, comprising:

a transmitting means for transmitting signals between a control device and the optical system;

a detecting means for detecting a light characteristic of the light received by the detector array during use on a presented object and for transmitting a signal indicative of said light characteristic via said transmitting means to the control device; and

an adjusting means for adjusting a light characteristic variable of said optical system for the succeeding objects when the received light characteristic for at least one of the previous objects is deficient.

2. A control system as claimed in claim 1 wherein said adjusting means adjusts a light characteristic variable which is one of detector array scan rate, integration time, and light output level of a light source.

3. A control system as claimed in claim 2 wherein said detecting means also detects and wherein said adjusting means also adjusts detector array calibrations.

4. A control system as claimed in claim 3 wherein said detecting means also detects and wherein said adjusting means also adjusts detector array threshold limits.

5. A control system as claimed in claim 4 wherein said detecting means also detects and wherein said adjusting means also adjusts the detector array dump timing.

6. A control system as claimed in claim 5 wherein said detecting means also detects and wherein said adjusting means also adjusts measurement limits of the optical system.

7. A control system as claimed in claim 5 wherein said optical system includes a color sensitivity camera, wherein said detecting means detects and said adjusting means adjusts the color sensitivity.

8. A control system as claimed in claim 2 wherein the machine vision is of a moving element, and wherein said detecting means also detects and said adjusting means also adjusts the rate at which the element moves.

9. A control system as claimed in claim 2 wherein the machine vision is of a moving element which is stopped for a period of time, and wherein said detecting means also detects and said adjusting means also adjusts the dwell time of the stopped element.

10. A control system as claimed in claim 2 wherein said adjusting means includes a blow-off means for directing a jet air against the window of the detector array to clean light obscuring debris from the window.

11. A control system as claimed in claim 10 wherein said blow-off means also directs a jet of air against an object being viewed to clean non light reflecting debris from the object.

12. A control system as claimed in claim 2 and further including computer means for initially receiving the detected light characteristic variables produced by a sample operation of the optical system and for determining appropriate values for the variables which are then automatically adjusted in the optical system by said adjusting means.

13. A control system as claimed in claim 12 wherein said transmitting means includes modem means for transmitting the signals over telephone lines from said detecting means to said adjusting means.

14. A method of controlling a detector array based optical system using light received by a detector array for machine vision from a plurality of succeedingly presented objects comprising the steps of:

detecting a light characteristic of the light received by the detector array from a presented object during use;

transmitting a signal indicative of the light characteristic to a remotely located control system; and

adjusting a light characteristic variable of the optical system for succeeding objects when the received signal of at least one previous object is deficient.

15. A method of controlling an optical system as claimed in claim 14 wherein the light characteristic variable is one of detector array scan rate, integration time, and light power output level of a light source.

16. A method of controlling an optical system as claimed in claim 15 and further including the steps of initially operating the machine vision under sampling conditions to obtain sample light characteristic values and thereafter setting the light characteristic variables to accommodate these sampling values.

17. A method of linearizing the ouput of a detector array using a microprocessor comprising the step of:

setting up an element correction array in the memory of the microprocessor corresponding to the detector array;

inputting precise object movement data to the microprocessor from an encoding device as an object is moved past the elements of the detector array;

comparing the data from the encoder with the data from the detector array at each array element and inputting an indication of the difference between the two sets of data as offset values at the corresponding positions in the element correction array; and

during the operating mode of the detector array, modifying the corresponding element correction array offset value to each detector array element reading to obtain a corrected detector array output which is substantially linear.

18. A method of linearizing as claimed in claim 17 and further including the steps of

remoting the microcomputer from the detector array;

and

transmitting the data to the microcomputer over suitable transmission lines.

19. A method of linearizing as claimed in claim 18 and further including the step of periodically recalculating the offset values remotely by a signal from the microprocessor.

20. An apparatus for linearizing the output of a detector array comprising:

a microprocessor having a memory in which an element correction array corresponding to the detector array is set up;

an encoding means for inputting precise object movement data to the microprocessor as an object is moved past the elements of the detector array;

a comparing means for comparing the data from said encoding means with the data from the detector array at each array element and for inputting an indication of this difference between the two sets of data as offset values at the corresponding positions in the element correction array; and

a modifying means for modifying the corresponding element correction array offset valve to each detector array element reading during operation to obtain a corrected detector array output which is substantially linear.

21. An apparatus for linearizing as claimed in claim 20 wherein said microprocessor is remotely located from the diode array and further including a transmitting means for transmitting the data between the microprocessor and the diode array.