Image processing apparatus for image reduction processing and control method thereof

An image processing apparatus that reduces an original image and generates a reduced image having a set reduction ratio, the apparatus comprising:

• a first reduction unit adapted to apply reduction processing to the original image using a variable reduction ratio and outputs a first reduced image;
• a second reduction unit adapted to apply reduction processing using a fixed reduction ratio to the first reduced image and output a second reduced image;
• at least one third reduction unit, which is connected to a subsequent stage of the second reduction unit, adapted to apply, at least once, the reduction processing using the fixed reduction ratio to the second reduced image;
• and
• a selection unit adapted to select the reduced image having the set reduction ratio and a reduced image having higher reduction ratio than the set reduction ratio output from a reduction unit, among the second reduction unit and the at least one third reduction unit, that is connected to any subsequent stages of the reduction unit that outputs the reduced image having the set reduction ratio, and store the selected reduced images in a storage device,
• wherein in a case where the set reduction ratio is higher than a highest value of the variable reduction ratio, the first reduction unit sets the variable reduction ratio such that the set reduction ratio can be achieved through a combination of the reduction processing by the first reduction unit and at least one instance of the reduction processing using the fixed reduction ratio, and one of the second reduction unit and the at least one third reduction unit outputs a reduced image having the set reduction ratio.