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.

Real-Time Chromakey Matting Using Image Statistics

Abstract: A method, system and computer readable media for real-time chromakey matting using image statistics. To identify the chroma key spectrum, the system/method executes in three stages. In an off-line training stage, the system performs semi-automatic calibration of the chroma key parameterization. In the real-time classification stage, the system estimates the alpha matte on a GPU. Finally, an optional error minimization stage improves the estimated matte, accounting for misclassifications and signal noise. Given the resulting matte, standard alpha blending composites the virtual scene with the video feed to create the illusion that both worlds coexist.

Hybrid hardware-accelerated image composition for sort-last parallel rendering on graphics clusters with commodity image compositor

Abstract: Hardware-accelerated image composition for sort-last parallel rendering has received increasing attention as an effective solution to increased performance demands brought about by the recent advances in commodity graphics accelerators. So far, several different hardware solutions for alpha and depth compositing have been proposed and a few of them have become commercially available. They share impressive compositing speed and high scalability. However, the cost makes it prohibitively expensive to build a large visualization system. In this paper, we used a hardware image compositor marketed by Mitsubishi Precision Co., Ltd. (MPC) which is now available as an independent device enabling the building of our own visualization cluster. This device is based on binary compositing tree architecture, and the scalable cascade interconnection makes it possible to build a large visualization system. However, we focused on a minimal configuration PC cluster using only one compositing device while taking cost into consideration. In order to emulate this cascade interconnection of MPC compositors, we propose and evaluate the hybrid hardware-assisted image composition method which uses the OpenGL alpha blending capability of the graphics boards for assisting the hardware image composition process. Preliminary experiments show that the use of graphics boards diminished the performance degradation when using an emulation based on image feedback through available interconnection network. We found that this proposed method becomes an important alternative for providing high performance image composition at a reasonable cost.

Method for alpha blending images utilizing a visual instruction set

Abstract: An image alpha blending method utilizing a parallel processor is provided. The computer-implemented method includes the steps of loading unaligned multiple word components into a processor in one machine instruction, each word component associated with a pixel of an image; alpha blending the multiple word components of different source images and a control image in parallel; and storing the alpha blended multiple word components of a destination image into memory in parallel.

Region selection for image compositing

Abstract: A technique for image compositing which allows a user to select the best image of an object, such as for example a person, from a set of images interactively and see how it will be assembled into a final photomontage. A user can select a source image from the set of images as an initial composite image. A region, representing a set of pixels to be replaced, is chosen by the user in the composite image. A corresponding same region is reflected in one or more source images, one of which will be selected by the user for painting into the composite image. The technique optimizes the selection of pixels around the user-chosen region or regions for cut points that will be least likely to show seams where the source images are merged in the composite image.

Image compositing device and image compositing method

Abstract: It is an object to generate a desired composite image in which a motion area of a subject is correctly composited. A difference image between a base target and an aligned swap target is generated (S 1021 ), and an extracted contour in the difference image is determined according to the active contour model (S 1022 ). The inner area of the contour and the outer area of the contour are painted with different colors to be color-coded so as to generate a mask image for alpha blending (S 1023 ). Using the mask image thus generated, the swap target that is aligned with respect to the base target is composited with the base target of the base image by alpha blending (S 1024 ).