Image data storing system

• US 4,761,643 A
• Filed: 03/11/1986
• Issued: 08/02/1988
• Est. Priority Date: 05/31/1982
• Status: Expired due to Fees

• Current Assignee: Fuji Xerox Company Limited (Fujifilm Holdings Corporation)
• Original Assignee: Fuji Xerox Company Limited (Fujifilm Holdings Corporation)
• Inventors: Fujiwara, Fukumi
• Primary Examiner(s): Brigance, Gerald L.
• Assistant Examiner(s): Brier, Jeffery A.
• Application Number:
  US06/838,448
• Time in Patent Office: 875 Days
• Field of Search: 340/723, 340/724, 340/725, 340/726, 340/744, 340/747, 340/789, 340/798, 340/799, 340/800, 340/750, 364/521
• US Class Current: 345/539
• CPC Class Codes: H04N 1/32112 in a separate computer file, document page or paper sheet, e.g. a fax cover sheet H04N1/32122 takes precedence
• CPC Class Codes: H04N 1/415 in which the picture-elements are subdivided or grouped into fixed one-dimensional or two-dimensional blocks
• CPC Class Codes: H04N 2201/3254 Orientation, e.g. landscape or portrait; Location or order of the image data, e.g. in memory
• CPC Class Codes: H04N 2201/3277 The additional information being stored in the same storage device as the image data

Abstract

An image data storage system and an apparatus and a method for compressing image data including a map memory and a data memory. The map memory contains a plurality of memory regions while the data memory contains a plurality of memory areas. A pointer is stored in each memory region of the map memory, one pointer for each corresponding unit of input data. For units of input image data containing other than all "0"s, the data is stored in a corresponding image data region of the data memory. On the other hand, for all image units containing all "0"s (completely white), the pointers point to a single memory data in the data memory which contains all "0"s.

Claims

1. An image data storage system for storing image data representing an image, said system comprising:

a map memory having a two-dimensional format and being divided into a plurality of (p×

q) of memory regions corresponding to (p×

q) image units which may or may not contain image information, said image units being obtained by two-dimensionally dividing an image, each of said image units consisting of a matrix of M×

N bits, wherein p is the number of image units in the horizontal scanning direction;

q, the number of image units in the vertical scanning direction;

M, the number of bits in one image unit in the horizontal scanning direction; and

N, the number of bits in one image unit in the vertical scanning direction, and

a data memory for storing image data representing said image units, each said memory region in said map memory storing a pointer which indicates an address of said data memory at which said image data are stored when image information exists in said one image unit, said map memory storing a predetermined number when no image information exists in said one image unit, wherein said data memory is not accessed for a particular map memory location when said location contains said predetermined number.

2. The image data storage system as claimed in claim 1, further comprising:

data detecting means, connected to said data memory and said map memory via a memory bus and a register, for detecting whether said image data representing each of said image units are all "0"s.

3. The image storage system as claimed in claim 1, further comprising:

data generating means, connected to said data memory and said map memory via a memory bus, for generating "0" data as said image data when said image data in each said memory region of said map memory are all "0"s.

4. The image data storage system as claimed in claim 1, wherein said pointer indicates a top address of said data memory

corresponding to a top position of stack of stored image data comprising the corresponding image unit in a map memory region storing said pointer.

5. The image data storage system as claimed in claim 1, wherein said predetermined number if "0".

6. The image data storage system as claimed in claim 1, further comprising:

first and second memory buffers, each having a capacity of 2^M ×

N, wherein M is a number such that 2^M ≧

P, wherein P is a number of words contained in each line of image data; and

means for continuously reading image data, wherein image data stored in one of said first and second memory buffers is read out while storage of the image data is being carried out in the other of said first and second memory buffers.

7. The image data storage system as claimed in claim 3, wherein said "0" data generated by said data generating means is stored in a corresponding memory region of said map memory.

8. A method for operating an image conversion system which includes a buffer to which an image input signal is applied in data words of a predetermined number of data bits, first means for detecting the end of each line in said image input signal, second means for counting an output of said first means to count a number of lines, a map memory which is addressed each time one word of said image input signal is received, a data memory having a plurality of memory areas, each of which corresponds to a respective pointer stored in said map memory, a first pointer register to which a first pointer value of said map memory is inputted, a second pointer register to which a predetermined value is inputted, and third means for setting a new pointer value in said first pointer register, said method comprising the steps of:

(1) if data of one word applied to said buffer are data other than all "0"s and the corresponding pointer value of said map memory inputted to said first pointer register is "0", storing data of said second pointer register in said map memory and writing the data of said one word in said data memory with said predetermined value as an address;

(2) if data of said one word applied to said buffer are data other than all "0"s and the corresponding pointer value of said map memory inputted to said first pointer register is not "0", writing the data of said one word into said data memory with said first pointer value as an address;

(3) if data of said one word applied to said buffer is all "0"s, returning to said step (1) and processing a new data word in said buffer without accessing said map memory and data memory; and

(4) repeating said steps (1) to (3) the same number of times as a predetermined number of lines for a region of said map memory which corresponds to one unit of an image to be converted.