Image processing apparatus and method, and storage medium

An image processing method, comprising:

• a detection step, of detecting the size of image data to be coded;
• a first transform step, of frequency-transforming, in a one-dimensional direction, image data to be coded;
• a second transform step, of further frequency-transforming, in a different one-dimensional direction, all of the frequency components obtained in said first transform step when the detected size is smaller than a predetermined size, and of frequency-transforming, in the different one-dimensional direction, at least some of the frequency components obtained in said first transform step when the detected size is equal to or greater than the predetermined size;
• and
• a coding step, of entropy-coding frequency components obtained in said second transform step, and of entropy-coding frequency components which are not frequency transformed in said second transform step among the frequency components obtained in said first transform step.

A computer-readable storage medium storing an image processing program comprising:

• code for detecting the size of image data to be coded;
• first transform code for frequency-transforming, in a one-dimensional direction, image data to be coded;
• second transform code for further frequency-transforming, in a different one-dimensional direction, all of the frequency components obtained by said first transform code when said detected size is smaller than a predetermined size, and for further frequency-transforming, in the different one-dimensional direction, at least some of the frequency components obtained by said first transform code when said detected size is equal to or greater than the predetermined size;
• and
• code for entropy-coding frequency components obtained by said second transform code, and for entropy-coding frequency components which are not frequency transformed by said second transform code among the frequency components obtained by said first transform code.

An image processing apparatus, comprising:

• input means for inputting the same image data to be coded a plurality of times;
• first transform means for frequency-transforming, in a one-dimensional direction, the image data input from said input means an N-th time in order to obtain a first frequency component;
• second transform means for frequency-transforming, in said one-dimensional direction, image data input from said input means an M-th time, M being greater than N, in order to obtain a second frequency component;
• storage means for selectively storing either one of said first and second frequency components;
• and third transform means for frequency-transforming, in a different one-dimensional direction, one of the first and second frequency components stored in said storage means.

An image processing method, comprising:

• an input step, of inputting the same image data to be coded a plurality of times;
• a first transform step, of frequency-transforming, in a one-dimensional direction, the image data input an N-th time in order to obtain a first frequency component;
• a second transform step, of frequency-transforming, in said one-dimensional direction, the image data input an M-th time, M being greater than N, in order to obtain a second frequency component;
• a storing step, of selectively storing either one of said first and second frequency components in a storage means;
• and
• a third transform step, of frequency-transforming, in a different one-dimensional direction, one of the first or second frequency components stored in said storing step.

A computer-readable storage medium storing an image processing program comprising:

• code for inputting the same image data to be coded a plurality of times;
• first transform code for frequency-transforming, in a one-dimensional direction, the image data input an N-th time in order to obtain a first frequency component;
• second transform code for frequency-transforming, in said one-dimensional direction, the image data input an M-th time, M being greater than N, in order to obtain a second frequency component;
• code for selectively storing either one of said first and second frequency components in a storage means;
• and
• third transform code for frequency-transforming, in a different one-dimensional direction, one of the first or second frequency components stored in said storage means.