1. An image processing apparatus comprising: a local motion vector calculation section that sets blocks, which are divided regions of a frame image, with spacings interposed therebetween in the frame image, and calculates a motion vector, which corresponds to each set block, as a local motion vector (LMV); a block weight calculation section that calculates a block weight as a reliability indicator of the local motion vector (LMV) which corresponds to each block; and a global motion vector calculation section that inputs the local motion vectors (LMV) and the block weights, and calculates a global motion vector (GMV) which is a common motion vector to the plurality of blocks included in the frame image, wherein the block weight calculation section calculates a degree of reliability of the local motion vector (LMV) corresponding to each block of a target block and near-field blocks adjacent to the target block, and a degree of similarity between the local motion vectors (LMV) of the target block and each near-field block, and calculates the block weight through arithmetic processing to which the degree of reliability and the degree of similarity are applied, wherein the block weight calculation section extracts near-field blocks, of which the degrees of reliability are high, as reliable near-field blocks, extracts similar blocks, of which the degrees of similarity are high, among the reliable near-field blocks, and executes a process of setting a ratio of the similar blocks to the reliable near-field blocks as a weight of the target block, and wherein the local motion vector calculation section, the block weight calculation section, and the global motion vector calculation section are each implemented via at least one processor.