Information Recognition of Printed Quantum Dots Matrix Image under Uncorrected Conditions

Printed quantum dots (PQDs) record information and load it into complex images to realize printing information anti-counterfeiting. A dots extraction algorithm was proposed for phone to read this image’s information. After preprocessing the captured image with adaptive Otsu method, the dispersion of local pixel gray distribution was calculated and the tilt angles of the lattice was estimated. The PWM method was used to modulate the projection waveforms of the image on the X and Y axes to determine the spacing between points and grided the dot matrix. Finally, the dot matrix data was extracted in grid units. The algorithm has been measured by mobile app, the scanning and reading speed is within 300ms.