A Fast and Noise Tolerable Binarization Method for Automatic License Plate Recognition in the Open Environment in Taiwan

License plate recognition is widely used in our daily life. Image binarization, which is a process to convert an image to white and black, is an important step of license plate recognition. Among the proposed binarization methods, Otsu method is the most famous and commonly used one in a license plate recognition system since it is the fastest and can reach a comparable recognition accuracy. The main disadvantage of Otsu method is that it is sensitive to luminance effect and noise, and this property is impractical since most vehicle images are captured in an open environment. In this paper, we propose a system to improve the performance of automatic license plates reorganization in the open environment in Taiwan. Our system uses a binarization method which is inspired by the symmetry principles. Experimental results showed that when our method has a similar time complexity to that of Otsu, our method can improve the recognition rate up to 1.30 times better than Otsu.

Which Attribute of Ceiling Color Influences Perceived Room Height?

Objective: We investigate effects of the hue, saturation, and luminance of ceiling color on the perceived height of interior spaces. Background: Previous studies have reported that the perceived height of an interior space is influenced by the luminance of the ceiling, but not by the luminance contrast between ceiling and walls: brighter ceilings appeared higher than darker ceilings, irrespective of wall and floor luminance. However, these studies used solely achromatic colors. We report an experiment in which we extend these findings to effects of chromatic ceiling colors. Methods: We presented stereoscopic room simulations on a head-mounted display (Oculus Rift DK2) and varied hue (red, green, blue), saturation (low, high), and luminance (bright, dark) of the ceiling independently of each other. Results: We found the previously reported ceiling luminance effect to apply also to chromatic colors: subjects judged brighter ceilings to be higher than darker ceilings. The remaining color dimensions merely had a very small (hue) or virtually no effect (saturation) on perceived height. Conclusion: In order to maximize the perceived height of an interior space, we suggest painting the ceiling in the brightest possible color. The hue and saturation of the paint are only of minor importance. Application: The present study improves the empirical basis for interior design guidelines regarding effects of surface color on the perceived layout of interior spaces.

Defining the visual adaptation field for mesopic photometry: Effect of surrounding source position on peripheral adaptation

In CIE 191:2010, the Commission Internationale de l’Eclairage recommends a mesopic photometry system based on peripheral visual tasks. For implementation of the system, the visual adaptation field needs to be defined, taking into account the surrounding luminance effect on the state of adaptation. A series of vision experiments in the mesopic range has been conducted to measure the surrounding luminance effect with respect to the angle between a peripheral task point and a point source. The results show that the surrounding luminance effect at a peripheral task point decreases with increasing angle at a larger slope than existing models, such as the Stiles-Holladay equation, the Commission Internationale de l’Eclairage general disability glare formula and the Stiles–Crawford equation. A new model for the surrounding luminance effect is proposed.