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.

Encoding, transmitting and displaying a sequence of images using a difference image

Abstract: The present invention relates to encoding, transmitting and displaying a sequence of images in which a difference image indicative of the difference between an image of the sequence and a subsequent image of the sequence to be displayed is generated such that, when it is overlaid onto the image, the composite image and the difference image is identical to the subsequent image. The difference image may be generated by comparing a pixel subset of the subsequent image to corresponding pixels in the previous image, and setting the pixel as transparent if it is identical and passes a similarity test, and setting the pixel as opaque if it fails the test. A difference image may be combined with an adjacent difference image to form a composite difference image. A thin client (web browser) may receive the images using a networking protocol. The image overlaying may be based on alpha channel transparency or index based transparency to aid video compression.

Color Image Integrity Verification Using Shamir's Secret Sharing Scheme

Abstract: A Novel watermarking technique to verify the integrity of the lossless color image (BMP image) using Shamir’s (k,n)-threshold Secret-Sharing Scheme via the use of Portable Network Graphics (PNG) image is proposed. An authentication signal is generated for each block of color image which is transformed into several shares using Shamir’s secret sharing scheme. The coefficients of the polynomial used by the Shamir’s method are used as carriers to carry given authentication signals. The partial shares are embedded into an alpha channel plane. The alpha channel plane is then combined with the original lossless BMP color image to form a PNG image. Undesired white noise created in the resulting transparent stego-image is removed by carefully mapping the computed share values into a range of alpha channel values near their maximum value of 255 in the embedding process. In the process of verifying the integrity of the image the authentication signals are computed from the current block which is then compared with the extracted shares from the alpha channel plane for the corresponding block. If the authentication signals doesn’t match then that block is marked as tampered. The proposed image authentication method possesses the merits of losslessness during image verification, high sensitivity to image alterations, good tampering localization capability, and very low false acceptance and rejection ratios. Experimental results proving the effectiveness of the proposed methods are also included.

Watermark embedding method and apparatus, and system

Abstract: Disclosed is a watermark embedding method. The method includes receiving an original image, generating a watermark image based on the selected watermark pattern, generating an alpha blended stego image by alpha blending the original image and the watermark image, and providing the alpha blended stego image, in which the watermark image is generated by considering at least one of allowable pixel value range and alpha value α range of the watermark pattern applied to a first pixel of the original image, wherein the at least one of allowable pixel value range and alpha value α range are determined by the difference of pixel value of the first pixel between the original image and the stego image by embedding the watermark pattern to the first pixel.

Frame buffer random access memory and system.

Abstract: A frame buffer dynamic random access memory (FBRAM) (71) is disclosed that enables accelerated rendering of Z-buffered graphics primitives. The FBRAM converts read-modify-write transactions such as Z-buffer compare and RBG alpha blending into a write only operation. The FBRAM also implements two levels of internal pixel caches (56), a pixel ALU (58), and a four-way interleaved frame buffer.

Image compositing apparatus

Abstract: PROBLEM TO BE SOLVED: To speedily and exactly perform a diagnosis based on a thermal image. SOLUTION: This image compositing apparatus is provided with a pair of right and left infrared cameras, a pair of right and left visible cameras, and a first image compositing processing means for performing compositing processing of data outputted from the right and left infrared cameras and data outputted from the right and left visible cameras so that an observer can watch a three-dimensional(3D) thermal image and a 3D visible image in the state of overlapping these images.