SUBBAND DIVIDING DEVICE, IMAGE ENCODING DEVICE, SUBBAND RECONSTITUTING DEVICE, IMAGE DECODING DEVICE, MODEL TREE STRUCTURE ENCODING METHOD, ENCODING METHOD, DECODING METHOD, AND MEDIUM

PROBLEM TO BE SOLVED: To provide a subband dividing device, an image encoding device, a subband reconstituting device, a subband reconstituting device, an image decoding device, and medium which are applicable to moving picture encoding more effectively than before. SOLUTION: This invention is equipped with a 1st subband dividing means 21 which performs a loop back process for an end of an image and outputs a band-limited image signal when block-divisional images 22 obtained by dividing a source image 902 into blocks are divided into signals of different frequency bands, a 2nd subband dividing means 24 which performs a loop back process for an end of an image and outputs a band-limited image signal when the output image from the 1st subband dividing means 21 is further divided into signals of different frequency bands, and a 3rd subband dividing means 26 which outputs the band-limited image signal without performing any loop back process for the end of the image when the output image from the 2nd subband dividing means 24 is further different into signals of different frequency bands.