Method and system for decoding two-dimensional code using weighted average gray-scale algorithm

1. A method for decoding two-dimensional code using weighted average gray-scale algorithm, characterized by comprising:

segmenting a received two-dimensional code image into bit regions each containing one bit data;

presetting a shifting threshold, and shifting four original boundary lines of the bit region outwards by a distance of the shifting threshold to obtain four preset boundary lines;

calculating an average gray-scale value of the bit region using the weighted average algorithm by taking an overlapping area between pixels inside the four preset boundary lines and the bit region as a weight;

binarizing the two-dimensional code image according to the average gray-scale value of the bit region; and

decoding the binarized two-dimensional code image;

wherein a solution of calculating the overlapping area between pixels inside the four preset boundary lines and the bit region includes:

finding all the pixels inside the four preset boundary lines;

selecting one selected point from the pixel and recording coordinates of the selected point and a position relationships between the selected point boundary lines of the pixels;

calculating distances from the selected point to the four original boundary lines of the bit region and their position relationships;

calculating a length and a width of the overlapping area between the pixels and the bit region; and

calculating the overlapping area between the pixels and the bit region.

2. The method for decoding two-dimensional code using weighted average gray-scale algorithm according to claim 1 , wherein the shifting threshold is less than or equal to the width of one pixel.

3. The method for decoding two-dimensional code using weighted average gray-scale algorithm according to claim 1 , wherein the selected point is any one of the pixels.

4. The method for decoding two-dimensional code using weighted average gray-scale algorithm according to claim 1 , wherein calculating an average gray-scale value of the bit region using the weighted average algorithm by taking the overlapping area between pixels inside the four preset boundary lines and the bit region as a weight specifically includes:

assuming that k represents the number of pixels inside the four preset boundary lines, P i represents pixels, where i=1, 2, . . . , k, S i represents the overlapping area between the pixels P i and the bit region, S represents the area of the bit region, Gp i represents the gray-scale value of the pixels P i , and Gave represents the average gray-scale value of the bit region, then the average gray-scale value Gave of the bit region is:

Gave

=

∑

i

=

1

k

⁢

Gp

i

*

S

i

/

S

.

5. The method for decoding two-dimensional code using weighted average gray-scale algorithm according to claim 1 , wherein calculating an average gray-scale value of the bit region using the weighted average algorithm by taking the overlapping area between pixels inside the four present boundary lines and the bit region as a weight specifically includes:

assuming that k represents the number of pixels inside the four preset boundary lines, P i represents pixels, where i=1, 2, . . . , k, S i represents the overlapping area between the pixels P i and the bit region, Gp i represents the gray-scale value of the pixel P i , and Gave represents the average gray-scale value of the bit region, the average gray-scale value Gave of the bit region is:

Gave

=

∑

i

=

1

k

⁢

Gp

i

*

S

i

∑

i

=

1

k

⁢

S

i

.

6. The method for decoding two-dimensional code using weighted average gray-scale algorithm according to claim 1 , wherein binarizing the two-dimensional code image according to the average gray-scale value of the bit region specifically includes:

calculating a gray-scale threshold of the two-dimensional code image according to the average gray-scale value of the bit region by using the Otsu method; and

binarizing the bit region according to the gray-scale threshold so as to obtain the binarization of the two-dimensional code image.

7. The method for decoding two-dimensional code using weighted average gray-scale algorithm according to claim 1 , wherein binarizing the two-dimensional code image according to the average gray-scale value of the bit region specifically includes:

calculating a gray-scale threshold of the two-dimensional code image according to the average gray-scale value of the bit region by using the average value algorithm; and

binarizing the bit region according to the gray-scale threshold so as to obtain the binarization of the two-dimensional code image.