Reduction Condition of Flicker during Switching of Two-colors for Protection of Image Displayed on a Liquid Crystal Display

Abstract

When different colors are switched at a high speed, the human eye can only perceive a blended color. If this color mixing method is applied to display an image on a Liquid Crystal Display (LCD), the color perceived by the viewer will be different from the colors being switched. In other words, the color of the image obtained by capturing the LCD screen will be different from the color perceived by the human eye because the screen copy key of the personal computer (PC) or the digital camera can capture the momentary display. Thus, the captured image will be identical to the image used for switching display. If we use this method to display images on an LCD display in a space such as a laboratory or offi ce, we can improve image protection and prevent illegal copying of images containing confi dential information, as shown in Figure 1 [1]. The authors have previously measured the chromaticity of the colors displayed when two different colors are switched on an LCD [2]. As a result, it became clear that the chromaticity of the colors displayed by switching (the color perceived by the viewer) equals the average of the two colors used for switching. Furthermore, a method for estimating the chromaticity of the colors displayed through the switching was proposed. This estimation method helps create an image with swapped colors by modifying the color of the original image. However, fl icker may occur when the two colors are switched. Looking at fl ickering images may have a negative infl uence on the Reduction Condition of Flicker during Switching of Two-colors for Protection of Image Displayed on a Liquid Crystal Display