System and method for encoding and decoding large capacity 2-dimensional color bar code which can be color-corrected
Disclosed herein are a bar code encoding system and a bar code decoding system. The bar code encoding system includes a method for compressing the original data and adding data for error detection and correction to the compressed data to generate a large capacity 2-dimensional color bar code so as to be used as prints in an off-line environment and a large capacity 2-dimensional bar code pattern. The decoding system includes a method for receiving the prints including the 2-dimensional bar code generated by the encoding system through an input device such as a scanner and a camera, searching the 2-dimensional bar code to recognize it, performing color correction and error detection and correction, decompressing the compressed data to decode the original data.
1. A method for encoding a large capacity 2-dimensional color bar code that can be color-corrected, comprising the steps of:
forming a color correction pattern used for correcting the colors of the 2-dimensional bar code, the color correction pattern having all colors used for the 2-dimensional bar code and being located in a specific region of the bar code;
forming a 2-dimensional bar code start pattern for indicating a start point of the 2-dimensional bar code, the 2-dimensional bar code start pattern being composed of a plurality of square pixels, the 2-dimensional bar code start pattern including a one-dimensional pattern in which black and white portions are alternately arranged;
forming a 2-dimensional bar code search pattern having black and white stripes having a specific width in a right-angled equilateral triangle having two 2-dimensional bar code start patterns including the one-dimensional pattern as two sides thereof, lengths of X-axis and Y-axis sides of the right-angled equilateral triangle being identical to each other;
forming position correcting markers at end points of the X-axis and Y-axis sides of the 2-dimensional bar code search pattern and an intersection of lines respectively extended from the end points, respectively, each position correcting marker being in the form of square and having a predetermined number of pixels in horizontal and vertical directions, each position correcting marker having a black central pixel and white pixels surrounding the black central pixel; and
forming at least one meta data between the position correcting markers, the meta data including a ratio of height/width of the 2-dimensional bar code to a quantity of additional data for error correction, the meta data including additional data for correcting an error thereof.
2. The encoding method of claim 1 , wherein the colors used for the 2-dimensional bar code, each of which is in a square pattern, are arranged at the top of the 2-dimensional bar code search pattern.
3. The encoding method of claim 1 , wherein the right-angled two sides of the 2-dimensional bar code search pattern each include a plurality of bar code start patterns.
4. The encoding method of claim 1 , wherein the 2-dimensional bar code search pattern is located at the left top of the 2-dimensional bar code.
5. The encoding method of claim 1 , wherein each of the position correcting markers is formed in a tetragonal pattern for each recorded data block.
6. The encoding method of claim 1 , further comprising a step of forming virtual markers outside the 2-dimensional bar code to process data pattern coordinates that do not belong to any one of the corners of the 2-dimensional bar code when the position correcting markers cover only a part of the bar code, the virtual markers being obtained by extending position correcting markers disposed at the corners of the 2-dimensional bar code.
7. A system for encoding a large capacity 2-dimensional color bar code that can be color-corrected, comprising:
a pattern generator for generating a 2-dimensional bar code start pattern for indicating a start point of the 2-dimensional bar code and a bar code search pattern having black and white stripes having a specific width in a right-angled equilateral triangle having two 2-dimensional bar code start patterns as two sides thereof, the 2-dimensional bar code start pattern being composed of a plurality of square pixels and including a one-dimensional pattern in which black and white portions are alternately arranged, lengths of X-axis and Y-axis sides of the right-angled equilateral triangle being identical to each other;
a position correcting marker generator for forming position correcting markers at end points of the X-axis and Y-axis sides of the 2-dimensional bar code search pattern and an intersection of lines respectively extended from the end points, respectively, each position correcting marker being in the form of square and having a predetermined number of pixels in horizontal and vertical directions, each position correcting marker having a black central pixel and white pixels surrounding the black central pixel; and
a meta data generator for generating at least one meta data between the position correcting markers, the meta data including a ratio of a height/width of the 2-dimensional bar code to a quantity of additional data for error correction, the meta data including additional data for correcting an error thereof.
8. The encoding system of claim 7 , further comprising:
a data compressing unit for receiving the original data and compressing the received original data using an algorithm employing Hoffman code; and
a data adding unit for adding additional data for error detection/correction to the compressed data.
9. The encoding system of claim 7 , wherein the position correcting marker generator forms virtual markers outside the 2-dimensional bar code to process data pattern coordinates that do not belong to any one of the corners of the 2-dimensional bar code when the position correcting markers cover only a part of the bar code, the virtual markers being obtained by extending position correcting markers disposed at the corners of the 2-dimensional bar code.