Method and system for processing an image

A computer implemented method for pre-processing an image, wherein

• the image has a predetermined bit depth, the method comprising the steps of:
• in a level 1:
• performing a predetermined transform on the image, thereby decomposing the image in:
• a low frequency subband of the level 1 comprising low frequency components in both a horizontal direction and a vertical direction;
• at least one high frequency subband of the level 1 comprising high frequency components in at least one of the horizontal direction and the vertical direction;
• in a level n, with n going from 2 up to a predetermined N, and with N being at least 2:
• performing the predetermined transform on the low frequency subband of the level n−1, thereby decomposing the low frequency subband of the level n−1 in a low frequency subband and at least one high frequency subband of the level n;
• resizing each high frequency subband of the level n to the dimensions of the corresponding high frequency subband of the level n−1, such that each resized high frequency subband of the level n has an equal amount of pixels in a width direction and a height direction as the corresponding high frequency subband of the level n−1;
• subtracting each resized high frequency subband of the level n from the corresponding high frequency subband of the level n−1 to obtain at least onea corresponding subtracted subband of the level n−1;
• storing each corresponding subtracted subband of the level n−1 as part of a pre-processed image;
• and
• in the level N:
• storing the low frequency subband of the level N−1 as part of the pre-processed image, and
• wherein the method further comprises the step of converting the preprocessed image to the predetermined bit depth.