Weak Invisible Dot Matrix Recognition Algorithm Based on Image Processing and Frequency Modulation Pulse Duty Cycle

Aiming at the problem of weak invisible dot matrix data being interfered by the background in the process of reading, which leads to the accuracy and slow speed of the reading algorithm, and in order to promote the better application of this information hiding and printing anti-counterfeiting technology in various fields, this paper designs a weak invisible dot matrix reading algorithm based on the image processing and the duty cycle of FM pulse. Firstly, the background information is used to affine transform the image, and the background is filtered out by channel difference operation; subsequently, the Gauss-Laplace sharpening technique is used to enhance the details of the dot matrix image, and combined with the sub-area Otsu method of binarization and the size of the connectivity domain to discriminate the dot matrix. Then, the pulse width modulation (PWM) and segmented variable precision bisection algorithms are utilized to construct the dot matrix recognition matrix. Finally, the eigenvalue information of each position in the index matrix is used to read the dot matrix data. Through experimental tests, when the test data is 308 bits, the print resolution is 600 dpi, and the image is taken at multiple angles, the reading time and BER of the weak invisible dot matrix is controlled within 0.4 seconds and 2%, respectively. To summarize, the algorithm proposed in this paper effectively solves the problem of weakly invisible dot matrix information reading in the case of background interference.