Accelerated and Optimized Search of Imperceptible Color Vibration for Embedding Information into LCD images

Large, high-resolution displays are installed throughout the city as public displays. By superimposing invisible information on the images of these displays, large numbers of devices with cameras and sensors can communicate with the displays without prior pairing. Several applications have been proposed, such as operating robots or communicating information to users by displaying 2D codes on images. However, the display of 2D codes has the problem of compromising the appearance of displayed content. Abe et al. proposed a method of communicating with devices by superimposing invisible information using color vibration on images displayed on off-the-shelf liquid-crystal displays (LCD). Using this method, we can embed the information for devices in images without interfering with the displayed content. Abe et al. uses a simple serial loop operation to search for color pairs comprising a color vibration, which requires a very long processing time due to the huge search space. In this paper, we propose an accelerated and optimized search method for color pairs that constitute the imperceptible color vibration for embedding information on LCD images. To achieve fast color pair search, we parallelized the search process, which is previously done individually, by using arrays representing the amount of movement and an operation to extract elements from the array that satisfy the conditions. In addition, we investigate the amount of information that can be superimposed on nine color images using the imperceptible color vibration and clarify the applicability of embedding information into images using the color vibration.