A system for image processing, the system comprising: a processor; and a non-transitory computer readable storage medium storing computer-executable instructions that when executed cause the processor to perform operations comprising: receiving first data at a first bed position and second data at a second bed position; wherein the first bed position and the second bed position having an overlapping region; reconstructing a first image based on the first data; reconstructing a second image based on the second data; extracting third data corresponding to the overlapping region from the first data; extracting fourth data corresponding to the overlapping region from the second data; merging the third data and the fourth data to generate merged data; reconstructing a third image based on the merged data, the third image being of the overlapping region; and generating a fourth image through image composition based on the first image, the second image, and the third image, wherein the fourth image includes a first portion being same as a non-overlapping region of the first image and a second portion being same as a non-overlapping region of the second image, the system characterized in that the fourth image further includes a third portion being generated based on a first weight coefficient corresponding to the overlapping region in the first image, a second weight coefficient corresponding to the overlapping region in the second image, and a third weight coefficient corresponding to the third image, wherein one of the first weight coefficient, the second weight coefficient, and the third weight coefficient relates to a length of the overlapping region and a distance of a pixel in the overlapping region in one of the first image, the second image, and the third image to an edge of the one of the first image, the second image, and the third image. a processor; and a non-transitory computer readable storage medium storing computer-executable instructions that when executed cause the processor to perform operations comprising: receiving first data at a first bed position and second data at a second bed position; wherein the first bed position and the second bed position having an overlapping region; reconstructing a first image based on the first data; reconstructing a second image based on the second data; extracting third data corresponding to the overlapping region from the first data; extracting fourth data corresponding to the overlapping region from the second data; merging the third data and the fourth data to generate merged data; reconstructing a third image based on the merged data, the third image being of the overlapping region; and generating a fourth image through image composition based on the first image, the second image, and the third image, wherein the fourth image includes a first portion being same as a non-overlapping region of the first image and a second portion being same as a non-overlapping region of the second image, the system characterized in that the fourth image further includes a third portion being generated based on a first weight coefficient corresponding to the overlapping region in the first image, a second weight coefficient corresponding to the overlapping region in the second image, and a third weight coefficient corresponding to the third image, wherein one of the first weight coefficient, the second weight coefficient, and the third weight coefficient relates to a length of the overlapping region and a distance of a pixel in the overlapping region in one of the first image, the second image, and the third image to an edge of the one of the first image, the second image, and the third image. receiving first data at a first bed position and second data at a second bed position; wherein the first bed position and the second bed position having an overlapping region; reconstructing a first image based on the first data; reconstructing a second image based on the second data; extracting third data corresponding to the overlapping region from the first data; extracting fourth data corresponding to the overlapping region from the second data; merging the third data and the fourth data to generate merged data; reconstructing a third image based on the merged data, the third image being of the overlapping region; and generating a fourth image through image composition based on the first image, the second image, and the third image, wherein the fourth image includes a first portion being same as a non-overlapping region of the first image and a second portion being same as a non-overlapping region of the second image, the system characterized in that the fourth image further includes a third portion being generated based on a first weight coefficient corresponding to the overlapping region in the first image, a second weight coefficient corresponding to the overlapping region in the second image, and a third weight coefficient corresponding to the third image, wherein one of the first weight coefficient, the second weight coefficient, and the third weight coefficient relates to a length of the overlapping region and a distance of a pixel in the overlapping region in one of the first image, the second image, and the third image to an edge of the one of the first image, the second image, and the third image.