Patent ID: 7020327

Claim:
A code image decoding method comprising: (a) receiving a code image including a data area in which target data is encoded and expressed as an image in colors or shades and a parity area for determining whether the image formed in the data area is suitable for the target data; (b) discerning the data area and the parity area in the code image from each other; (c) recognizing colors or shades from the images expressed in the data area and the parity area; (d1) presetting and storing optimized parameters according to various illumination environments; (d2) selecting a parameter among the optimized parameters in consideration of an environment where the code image has been read; (e) normalizing a color or shade recognized from the code image on the basis of the selected parameter, and obtaining code values for the data area and the parity area; (f) calculating a first parity value using the code values for the data area; (g) calculating a second parity value using the code values for the parity area; (h) determining whether there are no parity errors, by comparing the first parity value with the second parity value; and (i) re-setting the parameter and repeating the above-described steps from the step (e), if parity errors are generated, wherein in the step (i), when the parameters are reset, the distribution of colors or shades obtained from the cells of a code image is ascertained, and the parameters and their weighted values are reset with reference to the ascertained distribution.