Alpha compositing

About: Alpha compositing is a research topic. Over the lifetime, 482 publications have been published within this topic receiving 11035 citations. The topic is also known as: alpha blend & alpha channel.

A covert communication method via PNG images based on the information sharing technique

Abstract: A covert communication method via PNG images based on the information sharing technique is proposed. In the method, a secret message is transformed into secret shares which are then embedded into the alpha channel of a cover image of the PNG format. By mapping the computed share values of the alpha channel into suitable ranges to yield a nearly uniformly and transparent stego-image. The R, G, and B channels of the steo-image are untouched in the process of message embedding so that the original appearance revealed by the color information of these three channels is kept, achieving the desired effect of steganography for covert communication.

Method for implementing radar video rendering display based on direct 3D (D3D) alpha blending technology

Abstract: The invention relates to a clear and diversified display which is capable of achieving effects of plane position indicator display, A-scope display, afterglow display and the like on radar under the condition that the real-time requirement is met by utilizing a direct 3D (D3D) alpha blending technology When D3D or open graphics library (Open GL) is utilized to perform texture mapping rendering to display a radar video and a texture coordinate transformation technology is utilized to perform infinite scaling, a ground power unit (GPU) performs an image scaling according to a certain interpolation algorithm, accordingly, definition of obtained image is poor, and image resolution ratio is inconsistent with a resolution ratio proportion scale after the radar video is subjected to coordinate transformation Besides, the achievement of afterglow display is extremely complicated, and the display effect is not entirely satisfactory The method has the remarkable advantages that the infinite scaling of the radar video can be achieved, the accuracy is not affected, the moore profiling can not be generated, the afterglow display of the A-scope display and the plane position indicator display can be achieved, the display effect is close to that of a plane position indicator display fluorescent displayer, plane position indicator display targets can be subjected to Block display, and size and quantities of targets can be conveniently distinguished by operating staffs

Alpha channel digital image watermarking method

Abstract: In this paper, a method for embedding a digital watermark onto a host imagepsilas alpha channel is described. Blending factors which form an alpha channel define the proportion of foreground and background colors which in turn are combined to result in an actual color for each pixel. Here, the blending factors corresponding to areas along edges in the host image is of interest. The host image is first divided into blocks of subimages. A dominant edge found in any subimage is used to divide the pixels on that block into three groups:the group of foreground-color only pixels, the group of background-color only pixels, and the group of foreground-background blended color pixels. The blending factors for the pixels in the last group are modified to embed each bit of a watermarking pattern. Because the modified pixels belong to the area around an image edge, change to the original image due to watermark embedding is less perceptible.