1. A method of processing image data by an image processor having a signal-processing portion for converting image signals from an image sensor into digital signals and outputting the converted signals as image data, the image data including pixel values, each having a brightness at a corresponding one of coordinate points arranged in directions of rows and columns, the method comprising: extracting pixel values for image data delivered from the signal-processing portion by shifting image data at regular intervals of time in a direction of a time axis; deciding pixel values by comparing each pixel value extracted by the pixel values extracting step against a previously set first threshold value and making a decision as to whether the pixel value is less than the first threshold value; finding first autocorrelation coefficients for pixel values which are possessed by pixels located at a same coordinate point defined by the image data over plural frames while being shifted at the regular intervals of time in the direction of the time axis; determining random noise in the image by making a decision as to whether autocorrelation coefficients are less than a previously set second threshold value and determining that the image data has suffered from deterioration of image quality due to random noise when the autocorrelation coefficients are less than the second threshold value; setting pixel values equal to or larger than the first threshold value as a second pixel value when the decision at the pixel values deciding step is that the pixel values of the pixels are equal to or larger than the first threshold value; finding second autocorrelation coefficients by extracting pixel values which are equal to or larger than the second pixel value and which are possessed by pixels located at the same coordinate point over plural frames accepted while being shifted at the regular intervals of time in the direction of the time axis and finding the autocorrelation coefficients of the extracted pixel values; deciding autocorrelation coefficients by making a decision as to whether the autocorrelation coefficients found in the second autocorrelation coefficients finding step are less than a previously set third threshold value; selecting pixels possessing pixel values having autocorrelation coefficients less than the third threshold value as pixels of a short-distance view of the image when the decision made at the autocorrelation coefficients deciding step is that the autocorrelation coefficients are less than the third threshold value; and making a correction for camera shake regarding the pixels of the short-distance view selected in the short-distance view selecting step.