Image coding method and image coding device
In a first step, an input image constituted of a region of interest and a region of non-interest is transformed into plural frequency component images through plural wavelet transforms. In a second step, part of the plural frequency component image is selected as control target images and a region corresponding to the region of interest and a region corresponding to the region of non-interest are set in each of the control target images in a unit of a predetermined coding block. In a third step, among image data of the frequency component images, image data of the region corresponding to the region of non-interest in each control target image is changed to a zero value. In a fourth step, in the unit of the coding block, bit plane coding is applied to the image data changed in the third step without changing a bit plane structure, thereby generating coded data.
1 . An image coding method comprising:
a first step of transforming an input image constituted of a region of interest and a region of non-interest into a plurality of frequency component images through a plurality of wavelet transforms;
a second step of selecting a part of the plural frequency component images as control target images and setting, in a unit of a predetermined coding block, a region corresponding to said region of interest and a region corresponding to said region of non-interest in each of said control target images;
a third step of applying, to image data of the plural frequency component images, processing of changing, to a zero value, image data of the region corresponding to said region of non-interest in each of said control target images; and
a fourth step of applying, in the unit of the coding block, bit plane coding to the image data changed in said third step without changing a bit plane structure, to generate coded data.
2 . An image coding method according to claim 1 , wherein
in said second step, the frequency component image obtained through any one of the plural wavelet transforms is selected from the plural frequency component images as the control target image.
3 . The image coding method according to claim 2 , wherein
in said second step, the frequency component image obtained through a first one of the plural wavelet transforms is selected from the plural frequency component images as the control target image.
4 . The image coding method according to claim 2 , wherein in said second step, the frequency component image of a lowest frequency component obtained through a final one of the plural wavelet transforms is selected from the plural frequency component images as the control target image.
5 . An image coding device comprising:
a transform unit transforming an input image constituted of a region of interest and a region of non-interest into a plurality of frequency component images through a plurality of wavelet transforms;
a setting unit selecting a part of the plural frequency component images as control target images and setting, in a unit of a predetermined coding block, a region corresponding to said region of interest and a region corresponding to said region of non-interest in each of said control target images;
a changing unit applying, to image data of the plural frequency component images, processing of changing, to a zero value, image data of the region corresponding to said region of non-interest in each of said control target images; and
a coding unit applying, in a unit of the coding block, bit plane coding to the image data changed by said changing unit without changing a bit plane structure, to generate coded data.
6 . The image coding device according to claim 5 , wherein
said setting unit selects, as the control target image, the frequency component image obtained through any one of the plural wavelet transforms from the plural frequency component images.
7 . The image coding device according to claim 6 , wherein
said setting unit selects, as the control target image, the frequency component image obtained through a first one of the plural wavelet transforms from the plural frequency component images.
8 . The image coding device according to claim 6 , wherein
said setting unit selects, from the plural frequency component images, as the control target image, the frequency component image of a lowest frequency component obtained through a final one of the plural wavelet transforms.