Calibration techniques for imaging devices
AssigneeKodak Polychrome Graphics LLC
InventorChristopher J. Edge
Life of this patent
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Abstract
The invention is directed to various calibration techniques for calibrating an imagining device such as a display device, a printer, or a scanner. The techniques may involve characterizing the imaging device with a device model such that an average error between expected outputs determined from the device model and measured outputs of the imaging device is on the order of an expected error, and adjusting image rendering on the imaging device to achieve a target behavior. The invention can achieve a balance between analytical behavior of the imaging device and measured output. In this manner, adjustments to image rendering may be more likely to improve color accuracy and less likely to overcompensate for errors that are expected.
Claims60
A method of calibrating an imaging device comprising:
- characterizing the imaging device with a device model such that an average error between expected outputs determined from the device model and measured outputs of the imaging device is on the order of an expected error;
- and
- adjusting image rendering on the imaging device to achieve a target behavior.
A method of calibrating an imaging device comprising:
- characterizing the imaging device with a device model having a set of adjustable parameters;
- measuring color output from the imaging device;
- and
- reducing error between the measured color output and expected color output as defined by the device model by adjusting the adjustable parameters of the device model.
A method of calibrating a cathode ray tube comprising:
- measuring outputs of the cathode ray tube for a subset of device values of the cathode ray tube;
- choosing one or more adjustable parameter values of a device model for the cathode ray tube such that an average error between expected outputs determined from the device model and measured outputs of the cathode ray tube is on the order of an expected error, wherein a number of the adjustable parameters is less than a number of measured outputs of the imaging device;
- and
- adjusting image data according to the device model to achieve a target behavior for the cathode ray tube.
A method of calibrating a cathode ray tube comprising:
- initializing a lookup table (LUT);
- adjusting settings of the cathode ray tube to substantially achieve a defined output;
- measuring output for a number of color values;
- choosing adjustable parameter values for a device model, wherein a number of adjustable parameters is less than a number of measured outputs;
- and
- generating entries for the LUT based on the device model.
A method comprising:
- measuring output of a display device;
- and
- displaying a substantially white trace during measurement to bias an output measurement.
A cathode ray tube calibrated such that:
- an average color error is approximately less than (0.75 delta e) from an analytical expected color output;
- and
- a maximum color error is approximately less than (1.5 delta e) from the analytical expected color output.
A set of cathode ray tubes, wherein each cathode ray tube in the set is calibrated such that:
- an average color error is approximately less than (0.75 delta e) from an analytical expected color output;
- and
- a maximum color error is approximately less than (1.5 delta e) from the analytical expected output.
A computer readable medium storing program code that when executed calibrates an imaging device by:
- characterizing the imaging device with a device model such that an average error between expected outputs determined from the device model and measured outputs of the imaging device is on the order of an expected error;
- and
- adjusting image rendering on the imaging device to achieve a target behavior.
A computer readable medium storing program code that when executed calibrates an imaging device by:
- characterizing the imaging device with a device model having a set of adjustable parameters;
- measuring color output from the imaging device;
- and
- reducing error between the measured color output and expected color output as defined by the device model by adjusting the adjustable parameters of the device model.
A computer readable medium storing program code that when executed calibrates a cathode ray tube by:
- measuring outputs of the cathode ray tube for a subset of device values of the cathode ray tube;
- choosing one or more adjustable parameter values of a device model for the cathode ray tube such that an average error between expected outputs determined from the device model and measured outputs of the cathode ray tube is on the order of an expected error, wherein a number of the adjustable parameters is less than a number of measured outputs of the imaging device;
- and
- adjusting image data according to the device model to achieve a target behavior for the cathode ray tube.
A computer readable medium storing program code that when executed calibrates a cathode ray tube by:
- initializing a lookup table (LUT);
- adjusting settings of the cathode ray tube to substantially achieve a defined output;
- measuring output for a number of color values;
- choosing adjustable parameter values for a device model, wherein a number of adjustable parameters is less than a number of measured outputs;
- and
- generating entries for the LUT based on the device model.
A computer readable medium storing program code that when executed:
- measures output of a display device;
- and
- displays a substantially white trace during measurement to bias an output measurement.
Dependencies are inferred from the claim text.