Such a map is achieved using the guided filters , i.e. filtering the image saliency under the guidance of the original image.
The resulting structure-consistent importance map pro- vides the key constraint to determine how much a pixel is allowed to shift from the original to the target image. Ideally we want the neighboring pixels with similar importance to shift together so that their structure as a group will not be distorted. Meanwhile the pixels with high importance should not shift much with respect to the neighboring pixels with similar importance, such that their shape remains close to the original. On contrary the pixels with low importance should be allowed to move more relative to the neighbors.