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US 6,593,934 B1Granted
Automatic gamma correction system for displays
AssigneeIndustrial Technology Research Institute
InventorsMing-Jiun Liaw, Ho-Hsin Yang, Yuh-Ren Shen
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Abstract
This invention is related to an automatic Gamma correction system in which a novel display driving circuitry is designed with a digital/analog converter (DAC), wherein the Gamma reference voltages as well as the corresponding gray-scale values are adjustable. Therefore, the present invention provides a greater degree of freedom for the realization of the correction of Gamma parameters so as to fit the curve representing the transfer function of the destination gray-scale values and the voltages required by the display driving circuitry.
Claims25
An automatic Gamma parameter correction system for displays, comprising:
- a plurality of sensors, disposed inside said display or outside said display for obtaining a voltage-to-luminance curve so as to evaluate a set of Gamma reference voltages;
- a main controller, connected to said sensors to serve as a main control circuit for said system, and further including a central process unit (CPU) and a memory for parameter calculation and data storage;
- a programmable Gamma voltage generating means, connected to said main controller and generating said set of Gamma reference voltages output into the input terminals of a set of programmable switches according to said Gamma reference voltages evaluated by a central process unit in said main controller, therefor said Gamma reference voltages are adjustable;
- a set of programmable switches, connected to said programmable Gamma voltage generating means so as to receive an output voltage and also connected to a switch control unit so as to interconnect the output terminals of said programmable switches and a voltage dividing circuit with a set of corresponding gray-scale values according to gray-scale signals with respect to a switch control unit;
- a switch control unit, having an input terminal connected to said main controller and the output terminals connected to said programmable switches, so that said switch control unit interconnects the output terminals of said programmable switches and said voltage dividing circuit having a series divided voltage points and then applies said Gamma reference voltages to the corresponding divided voltage points according to said corresponding gray-scale signals delivered from said central process unit, therefor said corresponding gray-scale signals are adjustable;
- and
- a voltage dividing circuit, implemented by using a digital-to-analog converter (DAC), having an input terminal connected to the output terminals of said programmable switches;
- wherein for an N-gray-scale system, said voltage dividing circuit output at least 2N divided voltages, and then said voltages are further connected to a series of output buffers;
- wherein during Gamma parameter correction operation, the parameters related to said system are determined;
- a voltage-to-luminance curve of said display is then evaluated by using said sensors according to said driving voltage range determined by the parameters;
- later, a destination function of said gray-scale-to-voltage transfer curve is determined by said main controller, and said transfer curve is further implemented by said voltage dividing circuit;
- then, said Gamma reference voltages required by said voltage dividing circuit as well as said corresponding gray-scale values are evaluated, that is both the Gamma reference voltages and the corresponding gray-scale values are adjustable by CPU evaluating;
- further, said Gamma reference voltages and said corresponding gray-scale values are interconnected by said programmable switches and said switch control unit, so as to build up a gray-scale-to-voltage curve;
- and said voltage dividing circuit outputs corresponding voltages to said output buffers according to said input gray-scale values of the image.
11 more elements
A method for measuring the voltage-to-luminance curve for automatic Gamma parameter correction for displays, comprising the steps of:
- (a) determining related parameters for said displays;
- (b) determining a driving voltage range according to said Gamma parameters;
- (c) measuring a voltage-to-luminance curve of said displays;
- (d) determining a destination function of gray-scale-to-voltage transfer curve;
- (e) evaluating a set of Gamma reference voltages required by a voltage dividing circuit as well as a set of corresponding gray-scale values;
- (f) interconnecting said Gamma reference voltages and said corresponding gray-scale values by using a set of programmable switches and a switch control unit, so as to build up a gray-scale-to-voltage curve;
- and
- (g) outputting corresponding voltages to a series of output buffers by using said voltage dividing circuit according to a set of input gray-scale values of the image.
5 more elements
A method for measuring the operating related parameter (temperature or/and luminance) for automatic Gamma parameters correction for displays, comprising the steps of:
- (a) measuring an operating related parameter (temperature or/and luminance) of said displays;
- (b) determining a voltage-to-luminance curve of said displays by using table-checking;
- (c) determining a destination function of a gray-scale-to-voltage transfer curve;
- (d) evaluating a set of Gamma reference voltages required by a voltage dividing circuit as well as a set of corresponding gray-scale values;
- (e) interconnecting said Gamma reference. voltages and said corresponding gray-scale values by using a set of programmable switches and a switch control unit, so as to build up a gray-scale-to-voltage curve;
- and
- (f) outputting corresponding voltages to a series of output buffers by using said voltage dividing circuit according to a set of input gray-scale values of the image.
4 more elements
A method for measuring the operating related parameter (temperature or/and luminance) for automatic Gamma parameter correction for displays, comprising the steps of:
- (a) measuring an operating related parameter (temperature or/and luminance) of said displays;
- (b) determining a set of Gamma reference voltages required by said voltage dividing circuit as well as a set of corresponding gray-scale values by using table-checking;
- (c) interconnecting said Gamma reference voltages and said corresponding gray-scale values by using a set of programmable switches and a switch control unit, so as to build up a gray-scale-to-voltage curve;
- and
- (d) outputting corresponding voltages to a series of output buffers by using said voltage dividing circuit according to a set of input gray-scale values of the image.
2 more elements
An automatic Gamma parameter correction system accompanied with at least a conventional data driver for displays, comprising:
- a plurality of sensors, disposed inside said display for sensing the relative luminance of a series of voltage signals so as to obtain a voltage-to-luminance curve;
- a main controller, connected to said sensors to serve as a main control circuit for said system, and further including a central process unit (CPU) and a memory for parameter calculation and data storage;
- a programmable Gamma voltage generating means, connected to said main controller and generating a set of Gamma reference voltages output into the input terminals of said data driver according to a set of reference voltages evaluated by said central process unit in said main controller;
- and
- at least a data driver, directly connected to said programmable Gamma voltage generating means and generating image driving signals delivered into said display according to said Gamma reference voltage outputs by said programmable Gamma voltage generating means.
2 more elements
A method for measuring the voltage-to-luminance curve for automatic Gamma parameter correction for displays, comprising the steps of:
- (a) determining related parameters for said displays;
- (b) determining a driving voltage range according to said Gamma parameters;
- (c) repeating (a) if said determined parameters exceed a driving voltage range for said displays;
- (d) measuring a voltage-to-luminance curve of said displays;
- (e) determining a destination function of gray-scale-to-voltage transfer curve;
- (f) evaluating a set of Gamma reference voltages required by a voltage dividing circuit as well as a set of corresponding gray-scale values;
- (g) interconnecting said Gamma reference voltages and said corresponding gray-scale value by using a set of programmable switches and a switch control unit, so as tobuild up a gray-scale-to-voltage curve;
- and
- (h) outputting a set of corresponding voltages according to a set of input gray-scale values of the image.
6 more elements
Dependencies are inferred from the claim text.