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.

Image processing device, and superimposed image generation method

Abstract: During a period in which it is necessary to display two or more images in a superimposed manner, an image generation block 54 of an information processing apparatus 10 supplies the data of the image concerned to a superimposition processing block 56. A first image acquisition block 60 and a second image acquisition block 62 of the superimposition processing block 56 acquire a first image and a second image, respectively, to be displayed in a superimposed manner. A luminance range adjustment block 64 adjusts at least one luminance range as required with amount of adjustment corresponding to ± value set to the second image. An output value computation block 68 executes the computation of alpha blending by use of the image after adjustment so as to determine the pixel value of a display image, thereby outputting the determined pixel value to an image output block 58.

Apparatus and method for encoding/decoding image containing gray alpha channel

Abstract: PROBLEM TO BE SOLVED: To provide an apparatus and method for encoding/decoding an image containing a gray alpha channel. SOLUTION: The apparatus for encoding an image includes a block data reception unit which receives image data of a block currently being inputted to the apparatus and classifies the current block either as a foreground image portion or as a background image portion according to values of gray alpha components in the current block; a foreground image encoding unit sequentially encoding the gray alpha components and brightness and hue components of the current block if the current block is classified as the foreground image portion; and a background image encoding unit encoding the the alpha components of the gray alpha components of the current block if the current block is classified as the background image portion. The apparatus for decoding an image containing a gray alpha channel includes a bitstream interpretation unit which interprets the bitstream in units of predetermined blocks and classifies a current block obtained as one of the interpretation results either as a foreground image portion or as a background image portion. COPYRIGHT: (C)2005,JPO&NCIPI

Improved Algorithm on Digital Image Matting

Abstract: Digital image matting is to extract the foreground objects with arbitrary shapes from an image. This paper proposes optimal and developed algorithms for image matting in the efficiency and user interaction, without solving an optimization problem, but transforms the optimization problem into the minimum weighted distance issues based on dynamic programming. This method begins from segmenting regions by a user with two different colors to identify the foreground and background, and then the algorithm will be automatically propagated according to sampling points. Thus we can calculate the alpha channel of the overall image. This method is much faster than the existing approaches of comparable quality.

Rendering system using sample images

Abstract: A system for rendering a multiplicity of dynamic three-dimensional objects in a virtual environment, the system comprising a memory for storing a plurality of sample images representing the objects viewed from different angles, the system further comprising processing means configured for: for each object to be displayed, selecting a sample image from the memory based on the angle of viewing the object, wherein the pixels of the sample image include an alpha channel value for identifying a plurality of different regions of the image; mapping the sample image to a polygon representing the location of the object in the environment, including performing multi-pass rendering of the sample image, wherein each pass is for rendering differently coloured regions of the sample image identified by the alpha channel values.

Accelerating Image Processing in Flash using SIMD Standard Operations

Abstract: Flash applications have played an integral role in shaping the interactivity of the Internet. Desktop Flash applications feature vector-based processing such as image and video processing to enhance the user experience. In response to these needs, Adobe has added graphics card based acceleration for vector processing in Flash applications starting with Flash Player 10. This solution is limited to computer systems that have the proper graphics card. In this paper, we investigate the possibility of making explicit use of Single Instruction Multiple Data instructions, specifically SSE in the Intel x86-64 platforms, to accelerate vector operations in a Flash application. We also discuss certain limitations of the Flash virtual machine. The data reveals that a 90-92% speedup can be achieved by using SSE instructions to accelerate the alpha blending image processing algorithm in a Flash application. The SSE instructions are accessed by providing a standardized limited native interface to the Flash application.