Abstract: Image data of a target pixel and peripheral pixels are stored in a memory. Using a most significant bit extractor circuit, 4 most significant bits of data are extracted from each image data. A histogram circuit generates a histogram of the extracted 4-bit data. Referring to the histogram, a data processor circuit (17) replaces the image data of the target pixel with a maximum value of the numbers of pixels having the same level and outputs the processed data. Then, a digit-complementing circuit converts the data output from the data processor circuit to 8-bit data and outputs the converted data. In this manner, a regular image is converted into an image similar to a draft-design image.

Abstract: An image signal processor detects deficient pixels, such as pixels having a white deficiency or a black deficiency, and corrects the image signal so that the pixel deficiency is not reproduced. A memory circuit holds a target pixel signal and peripheral signals, which correspond to the pixels adjacent to the target pixel. A deficiency detection circuit compares the level of the target pixel signal with the levels of the peripheral pixel signals to detect whether the target pixel is deficient. A deficiency correction circuit corrects the signal of a detected deficient pixel using information from nearby pixels.

Abstract: Image data of a target pixel and peripheral pixels are stored in a memory. Using a most significant bit extractor circuit, 4 most significant bits of data are extracted from each image data. A histogram circuit generates a histogram of the extracted 4-bit data. Referring to the histogram, a data processor circuit (17) replaces the image data of the target pixel with a maximum value of the numbers of pixels having the same level and outputs the processed data. Then, a digit-complementing circuit converts the data output from the data processor circuit to 8-bit data and outputs the converted data. In this manner, a regular image is converted into an image similar to a draft-design image.

Abstract: A method for correcting a deficient image signal without lowering the resolution of a display page. The method includes generating an image signal of a subject pixel and image signals of peripheral pixels arranged about the subject pixel. A maximum level and a minimum level of the image signals of the peripheral pixels are detected. The method generates a first reference value by adding a first offset value to the maximum level and a second reference value by subtracting a second offset value from the minimum level. The method further includes generating a correction signal using at least one of the image signals of the peripheral pixels, and replacing the deficient image signal with the correction signal when the level of the image signal of the subject pixel is greater than the first reference value or less than the second reference value.