PROBLEM TO BE SOLVED: To preferentially read out an area effective for diagnosis from encoded data and to rapidly obtain a necessary image.SOLUTION: An image input portion 11 captures the reproducible amount of a low-quality image capable of being performed by diagnosis support processing among an encoded image data stream by the control of an initial stream setting portion 18 and an input control portion 14. A captured data stream is decoded in a decoding portion 12 and an obtained two-dimensional image 13 is analyzed in a diagnosis support portion 16 for determining a positive area 17. By controlling the image input portion 11 so that the input control portion 14 preferentially captures a part of the positive area 17, the area effective for diagnosis is preferentially captured and reproduced in detail.
