Abstract:  Camera is utilized to capture target LED (Light Emitting Diode) image in OCC(Optical Camera Communication) system, the performance degradation of OCC system occurs due to outdoor ambient light interference. The strong sunlight causes great difficulty in decoding at the receiving end of OCC system, in order to solve the problem a Gradient-Harris decoding algorithm based on piecewise linear gray transformation is proposed. A set of OCC experimental system is built, original images are captured by camera at the receiving end of OCC experimental system, and the target LED array region is extracted by standard correlation coefficient matching method. The image of target LED array region is enhanced by segmented linear gray transformation, a Gradient-Harris decoding algorithm is used for shape extraction and state recognition of target LED array. The experimental results show that the proposed Gradient-Harris decoding algorithm based on piecewise linear gray transform is effective for OCC experimental system in strong sunlight environment, the average decoding rate is 128. 08 bit/ s, the average bit error rate is 4. 38 x 10-4, and the maximum communication distance is 55 m. 

Key words: optical camera communication, target light emitting diode (LED) array, image enhancement, Gradient-Harris decoding algorithm