READING BARCODES USING DIGITAL CAMERAS ... - KULIS

Figure 8: The barcode field of the full image shown in Figure 5.
Figure 9: The barcode field of the full image in Figure 6.
After barcode fields are cut out from the image, a threshold is applied on these fields using
the mean values of these fields. Then, the resulting image only contains the barcode lines
which indicate the barcode codes. The barcode codes are obtained using these images using
an algorithm that stores white and black lines together in arrays by determining positions of
these lines described above. Then, every barcode code is obtained using these array sizes.
Note that the reference sizes have to be considered to make codes meaningful. This
operation is given in Algorithm 5 below.
1. Construct a variable ‘refsize’ to indicate a reference size, and a variable ‘result’ for the result
code.
2. Select first array to be processed.
3. This array should contain black pixels. The refsize variable is set to this array size.
For all lines:
4. Select next array if any unselected array exists else go to step 8.
5. Divide this array size to refsize. The calculated floating value is stored as a variable
‘codeValbyRef’. Round this value to the closest integer.
6. If this array includes black pixels write logic ‘1’ for the corresponding amount of the
codeValByRef value to the result value. Go to step 4.
7. If this array includes white pixels write logic ‘0’ for the corresponding amount of the
codeValByRef value to the result value. Go to step 4.
8. The result value must be the 95 bits long barcode code.
Algorithm 5: Determining the Barcode Code
842