Method and apparatus for calibrating and adjusting a color imaging system

• US 5,694,227 A
• Filed: 07/15/1994
• Issued: 12/02/1997
• Est. Priority Date: 07/15/1994
• Status: Expired due to Term

• Current Assignee: Apple Computer Incorporated (Apple Inc.)
• Original Assignee: Apple Computer Incorporated (Apple Inc.)
• Inventors: Starkweather, Gary K.
• Primary Examiner(s): Kostak, Victor R.
• Application Number:
  US08/275,596
• Time in Patent Office: 1,236 Days
• Field of Search: 348/180, 348/181, 348/182, 348/179, 348/175, 348/177, 348/228, 348/657, 348/266, 348/336, 348/187, 348/184, 348/185, 348/806, 348/807, 348/745, 348/746, 348/747, 358/504, 358/505, 358/518, 358/500, 358/506, 358/507, 358/508, 358/509, 358/527, 356/402, 356/406, 356/407, 356/73, 356/416, 356/419, 356/420, 250/252.1 A
• US Class Current: 358/504
• CPC Class Codes: H04N 1/603 controlled by characteristics of the picture signal generator or the picture reproducer
• CPC Class Codes: H04N 25/136 using complementary colours

Abstract

A color calibration system comprises a processor for receiving and transmitting data. A first sensor coupled to the processor detects emissive color images for providing first color sampling data to the processor. A second sensor coupled to the processor detects reflective color images for providing second color sampling data to the processor. A color output device coupled to the processor is calibrated in response to data generated by at least one of the first and second sensors.

Claims

1. A color calibration system comprising:

a processor for receiving and transmitting data;

a single sensor, operatively coupled with said processor, including

a first multi-pixel area integrating sensor which detects raster-scanned emissive color energy and in response provides first color sampling data to the processor, and

a second multi-pixel area integrating sensor which detects reflective color energy and in response provides second color sampling data to the processor; and

a color output device which is calibrated by the processor in response to data provided by at least one of the first and second sensors.

2. The color calibration system according to claim 1, further comprising a sensor driver for instructing the processor in the operation of the first and second sensors.

3. The color calibration system according to claim 1, further comprising a color space for storing first and second color sampling data.

4. The color calibration system according to claim 3, further comprising a color transform engine for converting the stored color sampling data into output device profile data which is used in accurately producing color images at the color output device.

5. The color calibration system according to claim 1, further comprising sensor calibration memory for storing data used by the processor in calibrating the first and second sensors.

6. The color calibration system according to claim 1, wherein the color output device is a color printer.

7. The color calibration system according to claim 1, wherein the color output device is an emissive display device.

8. The color calibration system according to claim 1, wherein the first sensor further comprises:

a first transducer having a red filter which provides red sampling data;

a second transducer having a green filter which provides green sampling data; and

a third transducer having a blue filter which provides blue sampling data.

9. The color calibration system according to claim 1, wherein the second sensor further comprises:

a first transducer having a red filter which transmits red light,

a second transducer having a green filter which transmits green light; and

a third transducer having a blue filter which transmits blue light.

10. A method for calibrating a color imaging system comprising the steps of:

sampling color image data, using a sensor including both an emissive transducer and a reflective transducer, from an image source;

selecting from between said emissive transducer and said reflective transducer based on the image source;

storing said image data to a color space;

transforming the color space to a device profile; and

generating a calibrated image output as defined by the device profile.

11. The method for calibrating a color imaging system according to claim 10, wherein the sensor is calibrated prior to sampling the color image data from the image source.

12. The method for calibrating a color imaging system according to claim 10, wherein following the generation of the calibrated image output as defined by the device profile, the image output is sampled and the device profile adjusted.

13. The method for calibrating a color imaging system according to claim 12, wherein the sensor comprising both an emissive and reflective transducer is used for sampling color image data from the image output.

14. A color calibration system comprising:

means, including a sensor having both an emissive transducer and a reflective transducer, for sampling color image data from an image source;

means for storing sampled image data to a color space;

means for transforming the color space to a device profile; and

means for generating a calibrated image output as defined by the device profile.

15. The color calibration system according to claim 14, comprising processor means for controlling the sensor.

16. The color calibration system according to claim 15, wherein the calibrated image output is sampled and the resulting sampled color image data is used to adjust the device profile.

17. The color calibration system according to claim 16, wherein the image output is sampled using a sensor comprising both an emissive and reflective transducer.

18. A color calibration system comprising:

a processor for receiving and transmitting data;

a single sensor including a first sensor which detects emissive color energy and in response provides first color sampling data to the processor and a second sensor which detects reflective color energy and in response provides second color sampling data to the processor;

a color space for storing first and second color sampling data;

a color transform engine for converting stored color sampling data into first and second output device profile data which is used in producing color images at the color output device; and

a color output device which is calibrated by the processor in response to color sampling data provided by at least one of the first and second sensors, and iteratively re-calibrated by sampling output device-produced images and, in response to the sampled images, adjusting the output device profile data.

19. The color calibration system of claim 18, and further including means for selecting one of the first and second sensors which is capable of sampling the color energy that corresponds to a color sample from which said color sampling data is to be derived.

20. A color calibration system comprising:

a sample area;

three light sensors having respective optical axes oriented around a sample axis through said sample area;

light beam component color focusing and filtering means including three component color channels each disposed on the axis of a respective light sensor;

a half mirror having a surface oriented to partially reflect light reflected off a sample article and traveling along said sample axis; and

an illuminating source of broadband visible light directed onto said sample area.

21. The color calibration system of claim 20 wherein said illuminating source is positioned on the opposite side of said half mirror from said sample area.

22. The color calibration system of claim 21 and further comprising a lens disposed between said source and said half mirror.

23. The color calibration system of claim 20 wherein said illuminating source is positioned on the same side of said half mirror as said sample area.

24. The color calibration system of claim 23 further comprising emissive light sensor means including three component color channels, each said channel having

a respective light sensor, and

light beam component color filtering means;

and being disposed on a respective channel axis oriented around a second sample axis through an emissive sample area.

25. A color calibration system for calibrating a color output device, comprising:

a sensor, for sampling color image data from an image source, including an emissive transducer and a reflective transducer, and

transforming means, operatively coupled with said sensor, for transforming said sampled color image data into instructions for the color output device.

26. The color calibration system of claim 25, wherein said transforming means comprises:

first processor means for receiving and transmitting color image dam sampled by said sensor,

second processor means for determining said instructions, and

memory means for storing said instructions for said color output device.

27. The color calibration system of claim 26, wherein said transforming means further comprises a color transform engine for converting the stored color sampling data into said output device instructions which are used to produce color images at the color output device.

28. The color calibration system of claim 25, and further comprising sensor driver means for instructing the processor to receive color sampling data from one of the first and second transducers.