1. An image composition apparatus, comprising: an interface module, being configured to receive a plurality of images, wherein the images are aligned and are defined by a plurality of positions, each of the images comprises a pixel at each of the positions; and a processing unit, being electrically connected to the interface module and configured to calculate a respective confidence value for each pixel of each image and suppress a portion of the positions, wherein each suppressed position is suppressed according to at least the confidence values corresponding to the suppressed position, wherein the processing unit is further configured to determine a plurality of sub-regions for a composite image according to the unsuppressed positions, determine a source for each of the sub-regions, grow the sub-regions until the composite image is filled by the sub-regions, and fill each of the sub-regions by the pixels in a corresponding sub-region of the corresponding source, wherein each of the sources is one of the images.