Patent ID: 8340419

Claim:
An image processing device comprising: a grayscale conversion portion that performs grayscale conversion on an input signal that is made from pixel data that forms an image to obtain a converted signal; a noise reduction degree determining portion that determines a noise reduction degree for the converted signal based on (1) a signal level of the input signal and (2) a gain for grayscale conversion, the gain for grayscale conversion being (i) the ratio of the converted signal to the input signal and (ii) equal to (the converted signal)/(the input signal); and a noise reducing portion that executes noise reduction processing on the converted signal based on the noise reduction degree, wherein the noise reduction degree determining portion comprises: a first noise reduction degree calculation portion that, if the signal level of the input signal is larger than a predetermined signal level threshold, outputs a signal level-based noise reduction degree whose value is smaller than when the signal level of the input signal is equal to or less than the predetermined signal level threshold; a second noise reduction degree calculation portion that, if the gain for grayscale conversion, which is the ratio of the converted signal to the input signal (=(the converted signal)/(the input signal)), is larger than a predetermined gain threshold, outputs a gain-based noise reduction degree whose value is greater than when the gain for grayscale conversion is equal to or less than the predetermined gain threshold; and a noise reduction degree output portion that sets a value that has been calculated based on the signal level-based noise reduction degree and the gain-based noise reduction degree as the noise reduction degree.