Color sensor system for the recognition of objects with colored surfaces

• US 4,917,500 A
• Filed: 11/30/1988
• Issued: 04/17/1990
• Est. Priority Date: 12/03/1987
• Status: Expired due to Fees

• Current Assignee: Siemens AG
• Original Assignee: Siemens AG
• Inventors: Lugos, Attila
• Primary Examiner(s): Evans, F. L.
• Application Number:
  US07/278,092
• Time in Patent Office: 503 Days
• Field of Search: 356/402, 356/406, 356/407, 356/405, 356/425, 250/226
• US Class Current: 356/406
• CPC Class Codes: G01J 2001/444 Compensating; Calibrating, e.g. dark current, temperature drift, noise reduction or baseline correction; Adjusting
• CPC Class Codes: G01J 2003/466 Coded colour; Recognition of predetermined colour; Determining proximity to predetermined colour
• CPC Class Codes: G01J 3/02 Details
• CPC Class Codes: G01J 3/0218 using optical fibers
• CPC Class Codes: G01J 3/50 using electric radiation detectors
• CPC Class Codes: G01J 3/501 Colorimeters using spectrally-selective light sources, e.g. LEDs
• CPC Class Codes: G01N 2021/4742 comprising optical fibres
• CPC Class Codes: G01N 2201/0621 Supply
• CPC Class Codes: G01N 2201/12753 and storage

Abstract

The color sensor system has at least three electronic light transmitters each emitting light of a determined narrow-band range of wavelengths, which under the control of a transmission control device in the course of a control cycle, illuminate successively the colored surface of the object in question for a brief period of time with light pulses of a predetermined intensity. The light reflected in each case from the colored surface upon the arrival of the light pulses is received by an electronic light receiver and converted into electrical signals. The electrical signals that are emitted successively by the light receiver in the course of a control cycle are conducted to an evaluation device for a color determination.

Claims

1. A color sensor system for the recognition of objects having at least a partially colored surface, comprising:

at least three electronic light transmitters, each emitting light pulses in a predetermined narrow-band range of wavelengths;

a transmitter control device coupled to said electronic light transmitters for establishing at least one control cycle during which said light pulses successively illuminate said colored surface of an object;

an electronic light receiver for receiving light reflected from said colored surface in response to the arrival of each of said light pulses and converting them into individual electrical signals having an intensity corresponding to that of said reflected light;

an evaluation device coupled to said electronic light receiver for making a color recognition determination based on the intensity of said received individual electrical signals in the course of said control cycle;

at least one temperature sensor for supplying temperature data with regard to an ambient temperature to said transmitting control device and said evaluation device, wherein said transmitting control device supplies in the course of said control cycle to said electronic light transmitters current pulses which are individually determined in accordance with said temperature data and stored data relating to temperature-dependent emission curves of said light transmitters for successively illuminating said colored surface with light pulses of predetermined intensity, and wherein said evaluation device makes a compensation for said received individual signals based upon said temperature data and stored data relating to temperature-dependent conversion curves of said light receiver; and

means for comparing said received individual electrical signals with stored values for said color recognition determination.

2. The color sensor system according to claim 1, further comprising means for measuring the ambient light, said means for measuring supplying ambient light data to said evaluation device in the course of each said control cycle for compensating each individual signal.

3. The color sensor system according to claim 1, wherein said evaluation device includes storage means for storing color limit values as comparative color values for making an absolute color measurement, and storing predetermined color values for making a relative color measurement.

4. The color sensor system according to claim 1, wherein each of said light transmitters comprises a light emitting device for emitting said light of a predetermined narrow-band range of wavelengths, and a transmitting optical waveguide coupled thereto;

and

said light receiver comprises a photo semiconductor and a receiving optical waveguide coupled thereto, the free ends of said transmitting optical waveguides being arranged concentrically in a sensor head around the free end of said receiving optical waveguide.

5. The color sensor system according to claim 2, wherein each of said light transmitters comprises a light emitting device for emitting said light of a predetermined narrow-band range of wavelengths, and a transmitting optical waveguide coupled thereto;

and

said light receiver comprises a photo semiconductor and a receiving optical waveguide coupled thereto, the free ends of said transmitting optical waveguides being arranged concentrically in a sensor head around the free end of said receiving optical waveguide.

6. The color sensor system according to claim 3, wherein each of said light transmitters comprises a light emitting device for emitting said light of a predetermined narrow-band range of wavelengths, and a transmitting optical waveguide coupled thereto;

and

said light receiver comprises a photo semiconductor and a receiving optical waveguide coupled thereto, the free ends of said transmitting optical waveguides being arranged concentrically in a sensor head around the free end of said receiving optical waveguide.

7. The color sensor system according to claim 1, wherein said light transmitters each include at least one light emitting device, said light emitting devices being jointly coupled to a current control device, which receives from said transmission control device control signals corresponding to said current pulses that are supplied individually to said light transmitters, and wherein the output of said light receiver is coupled to the input of a regulating amplifier, which receives, conducted from said evaluation device, compensation signals for the compensation of said individual electrical signals.

8. The color sensor system according to claim 2, wherein the supplying of the temperature data and the measurement of the ambient light occurs within a control cycle before the emission of at least the first of said current pulses by said transmission control device.

9. A color sensor system for the recognition of objects having at least a partially colored surface, comprising:

at least three electronic light transmitters each emitting light pulses in a predetermined narrow-band range of wavelengths;

an electronic light receiver for receiving light reflected from said colored surface in response to the arrival of each of said light pulses and converting them into individual electrical signals having an intensity corresponding to that of said reflected light;

a micro-controller system coupled to said electronic light transmitters for establishing at least one control cycle during which said light pulses successively illuminate said colored surface of an object and coupled to said electronic light receiver for making a color recognition determination based on the intensity of said received individual electrical signals in the course of said control cycle;

at least one temperature sensor for supplying temperature data with regard to an ambient temperature to said micro-controller system which supplies in the course of said control cycle to said electronic light transmitters current pulses which are individually determined in accordance with said temperature data and stored data relating to temperature-dependent emission curves of said light transmitters for successively illuminating said colored surface with light pulses of predetermined intensity, and wherein said micro-controller system makes a compensation for said received individual signals based upon said temperature data and stored data relating to temperature-dependent conversion curves of said light receiver and, compares said received individual electrical signals with stored values for said color recognition determination.

10. The color sensor system according to claim 9, wherein said micro-controller system is coupled to external devices through at least one serial and at least one parallel interface and through interrupt inputs and outputs.

11. The color sensor system according to claim 9, wherein said micro-controller system includes storage means for storing color limit values as comparative color values for making an absolute color measurement, and storing predetermined color values for making a relative color measurement.

12. The color sensor system according to claim 9, wherein each of said light transmitters comprises a light emitting device for emitting said light of a predetermined narrow-band range of wavelengths and a transmitting optical waveguide coupled thereto;

and said light receiver comprises a photo semiconductor and a receiving optical waveguide coupled thereto, the free ends of said transmitting optical waveguides being arranged concentrically in a sensor head around the free end of said receiving optical waveguide.

13. The color sensor system according to claim 9, wherein said light transmitters each include at least one light emitting device;

said light emitting devices being jointly coupled to a current control device, which receives from said micro-controller system control signals corresponding to said current pulses that are supplied individually to said light transmitters, and wherein the output of said light receiver is coupled to the input of a regulating amplifier, which receives, conducted from said micro-controller system, compensation signals for the compensation of said individual electrical signals.