A method is provided. The method includes: obtaining a picture to be processed, where the picture to be processed includes a plurality of pixels, and the plurality of pixels comprise first pixels for forming an image and second pixels for forming an image background; rotating the picture to be processed, where for each rotation angle, an intermediate picture is obtained; selecting at least two pictures from the picture to be processed and several intermediate pictures for calculating an area of a bounding box surrounding the image respectively; and removing second pixels outside the bounding box in a picture with the smallest area of bounding box to obtain a processed picture.