1. A medical image processing apparatus, comprising: acquisition circuitry configured to acquire a first photographic image and a second photographic image that contain tree structures of a subject; extraction circuitry configured to extract branch points of each of the tree structures in the first photographic image and the second photographic image; calculation circuitry configured to calculate similarities between the branch points in the first photographic image and the branch points in the second photographic image based on feature quantities of the branch points; and determination circuitry configured to determine a corresponding path between the branch points in the second photographic image and the branch points in the first photographic image based on the similarities between the branch points calculated by the calculation circuitry, wherein the acquisition circuitry is configured to include: multi-level acquisition circuitry configured to divide a tree structure into a plurality of levels, taking a level where seed points locate as start points, acquire corresponding portions of the tree structure in the respective levels in turn, and combine the acquired portions into a complete tree structure, and method determination circuitry configured to evaluate acquisition results on a former level and, based on a result of the evaluation, determine acquisition method to be performed by the multi-level acquisition circuitry for a current level, and the method determination circuitry is configured to take the acquisition method for the level where the seed points locate as region growing and repeat a process of adaptively acquiring segmentation results of the current level by adaptively adjusting parameters of the current level based on feedback of the segmentation results on the former level until growth of a whole tree structure has been completed.