A line-by-line filter process is performed to extract luminance data and color carrier data from an original image (i.e., a CCDRAW image) obtained from a single-sensor color imaging element, without separating the original image into R, G, and B data corresponding to a Bayer array. A color difference data demodulation process and a median noise removal process are performed with respect to the color carrier data to obtain color difference data. Band limitation filter processes having different characteristics are performed with respect to the luminance data and the color difference data, respectively. Moreover, separate resizing processes are performed with respect to the luminance data and the color difference data, respectively. A modulation process is performed to convert the resized color difference data to color carrier data. A color array reproduction process is performed to recombine the color carrier data and the resized luminance signal.