Image processing method and apparatus, and computer product

An image processing method of coding bit data for each of bit planes that constitute an electronic image, the method comprising the steps of:

• extracting plural pieces of bit data that represent one pixel of the electronic image, as pixel data;
• specifying bit data that has a predetermined value and has the greatest bit plane number of the pieces of bit data having the predetermined value, among the extracted bit data;
• determining whether the bit plane number of the specified bit data is greater than a bit plane number stored in a predetermined storage circuit or storage region;
• and
• rewriting the bit plane number stored in the predetermined storage circuit or storage region to the bit plane number of the specified bit data if it is determined that the bit plane number of the specified bit data is greater than the bit plane number stored in the predetermined storage circuit or storage region.

An image processing program for coding bit data for each of bit planes that constitute an electronic image, the program allowing a computer to execute the steps of:

• specifying a bit plane from relevant bit planes among the bit planes, the relevant bit planes having plural pieces of bit data, the bit plane having the greatest bit plane number among bit planes having one piece of bit data having predetermined value;
• extracting plural pieces of bit data, as effective data, that constitute bit planes whose numbers are equal to or smaller than the bit plane number of the specified bit plane among the bit planes that constitute the electronic image;
• and
• coding the extracted bit data for each of the bit planes.

An image processing program for coding bit data for each of bit planes that constitute an electronic image, the image processing program allowing a computer to execute the steps of:

• extracting plural pieces of bit data that represent one pixel of the electronic image, as pixel data;
• specifying bit data that has a predetermined value and has the greatest bit plane number of the pieces of bit data having the predetermined value, among the extracted bit data;
• determining whether the bit plane number of the specified bit data is greater than a bit plane number stored in a predetermined storage circuit or storage region;
• and
• rewriting the bit plane number stored in the predetermined storage circuit or storage region to the bit plane number of the specified bit data if it is determined that the bit plane number of the specified bit data is greater than the bit plane number stored in the predetermined storage circuit or storage region.

An image processing apparatus that codes bit data for each of bit planes that constitute an electronic image, the apparatus comprising:

• a specification unit that specifies a bit plane from relevant bit planes among the bit planes, the relevant bit planes having plural pieces of bit data, the bit plane having the greatest bit plane number among bit planes having one piece of bit data having predetermined value;
• an effective data extraction unit that extracts plural pieces of bit data that constitute bit planes whose bit plane numbers are equal to or smaller than the bit plane number of the specified bit plane among the bit planes that constitute the electronic image;
• and
• a coding unit that codes the bit data extracted by the effective data extraction unit for each of the bit planes.

An image processing apparatus that codes bit data for each of bit planes that constitute an electronic image, the apparatus comprising:

• a pixel data extraction unit that extracts plural pieces of bit data that represent one pixel of the electronic image;
• a specification unit that specifies bit data that has a predetermined value and has the greater bit plane number of the pieces of bit data having the predetermined value, among the bit data extracted by the pixel data extraction unit;
• a determination unit that determines whether the bit plane number of the bit data specified by the specification unit is greater than a bit plane number stored in a predetermined storage circuit or storage region;
• and
• a rewrite unit that rewrites the bit plane number stored in the predetermined storage circuit or storage region to the bit plane number of the bit data specified by the specification unit if it is determined by the determination unit that the bit plane number of the specified bit data is greater than the bit plane number stored in the predetermined storage circuit or storage region.