Abstract: A method and apparatus for removing false contours in a pulse number modulation (PNM) digital display device having a plasma display panel (PDP). The method involves a) comparing the input data with the comparison data and calculating a plurality of possible output data in consideration of an index error between the input data and error-diffused input data so that the false contours can be removed, the error-diffused input data being obtained by diffusing a quantization error that has occurred in pixels adjacent to the input data in the current frame; b) detecting an index error between the input data and the error-diffused input data; and c) selecting one from among the plurality of possible output data obtained in step a) in consideration of the index error detected in step b).

Abstract: Apparatus and method for controlling a driving voltage for an image display device, in which an optical sensor is installed between a liquid crystal display device and a screen or between the liquid crystal display device and a projection lens, and the driving voltage for the liquid crystal display device is feedback controlled using the output signal of the optical sensor in order to provide an optimal contrast. In this apparatus and method, the edge area of an image display device is subject to a minute change in the amplitude of a driving voltage, and the optical change is sensed and used to control the driving voltage of the image display device. Accordingly, regardless of property changes due to the temperature of an image display device and its peripheral devices, a picture can be displayed with an optimal contrast and blinking due to flickering can be minimized.

Abstract: A method and apparatus for removing false contours in a pulse number modulation (PNM) digital display device having a plasma display panel (PDP). The method involves a) comparing the input data with the comparison data and calculating a plurality of possible output data in consideration of an index error between the input data and error-diffused input data so that the false contours can be removed, the error-diffused input data being obtained by diffusing a quantization error that has occurred in pixels adjacent to the input data in the current frame; b) detecting an index error between the input data and the error-diffused input data; and c) selecting one from among the plurality of possible output data obtained in step a) in consideration of the index error detected in step b).

Abstract: Apparatus and method for controlling a driving voltage for an image display device, in which an optical sensor is installed between a liquid crystal display device and a screen or between the liquid crystal display device and a projection lens, and the driving voltage for the liquid crystal display device is feedback controlled using the output signal of the optical sensor in order to provide an optimal contrast. In this apparatus and method, the edge area of an image display device is subject to a minute change in the amplitude of a driving voltage, and the optical change is sensed and used to control the driving voltage of the image display device. Accordingly, regardless of property changes due to the temperature of an image display device and its peripheral devices, a picture can be displayed with an optimal contrast and blinking due to flickering can be minimized.