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.

Dual Watermarking For High Protective Copyright System

Abstract: Dual Watermarking is used forcopyright protection and authentication. In theproposed system, a Dual Watermarking Schemebased on BPCS and Alpha Channel maskingalgorithm, will be developed to improve therobustness and protection along with security.Our project implemented the BPCS (Bit Plane Complexity Segmentation) technique to embed data into bitmap files. The ultimate goal is to embed as much data as possible into a cover image without detection by human perception or statistical analysis. Our first attempt to implement this hiding technique was on 8-bit grayscale images as our cover object. After accomplishing that version, we manipulated it into a second version that was also capable of using 24-bit color images.First outline the BPCS embedding and extraction technique for grayscale images and explain the subtle differences in the color version. It will also compare and contrast the results of embedding data at different thresholds and capacities for both grayscale and color images.

Method and apparatus for alpha blending images from different color formats

Abstract: In some examples, an apparatus obtains source layer pixels, such as those of a content image and first destination layer pixels, such as those of a destination image. The first destination layer pixels have associated alpha values. The apparatus obtains information that indicates a first blending color format for the alpha values. The first blending color format is different from a first destination layer color format for the first destination layer pixels and an output color format for a display. The apparatus converts the source and/or first destination layer pixels to the first blending color format. The apparatus generates first alpha blended pixels based on alpha blending the source layer pixels with the first destination layer pixels using the associated alpha values. The apparatus provides, for display on the display, the first alpha blended pixels.

Alpha channel power savings in graphics unit

Abstract: A graphics processing circuit and method for power savings in the same is disclosed. In one embodiment, a graphics processing circuit includes a number of channels. The number of channels includes a number of color component channels that are each configured to process color components of pixel values of an incoming frame of graphics information. The number of channels also includes an alpha scaling channel configured to process alpha values (indicative of a level of transparency) for the incoming and/or outgoing frames. The graphics processing circuit also includes a control circuit. The control circuit is configured to place the alpha scaling channel into a low-power state responsive to determining that at least one of the incoming or outgoing frames does not include alpha values.

Image processing method and system

Abstract: The embodiment of the invention provides an image processing method and system, wherein the method comprises the following steps of dividing an image to be processed into a foreground region, a background region and an uncertain region according to green component difference values of various pixel points in the image to be processed; determining a reconstruction background image according to the background region; re-calculating the foreground region and the uncertain region according to the reconstruction background image to obtain a reconstruction foreground image; obtaining a reconstruction alpha channel value according to a comparison result of the reconstruction foreground image and a set threshold value; and re-synthesizing the image according to the reconstruction foreground image, the reconstruction alpha channel value and a background image to be synthesized, such that a synthesized image is obtained. By means of the embodiment of the invention, the problem that colour overflows from the image due to existing ambient light interference can be solved.

Greyscale image authentication and repairing

Abstract: It is very necessary to design effective methods to solve image authentication problem, particularly f or images whose security must be protected. In digital documents it is necessary to provide data authentication and repairing of tamper ed data e.g. important documents such as certificates, scanned cheques, drawings, circuit diagrams, signed documents, desig n draft etc. In this paper, a technique for authentication of images with self-re pair capability for fixing tampered image data is eThe input image is assumed to be a binary-type greyscale image with 2 main gray values. Alpha channel is combined in the greyscale image .Using the binary image, authentication signal is calculated w hich is then embedded in the alpha channel to creat e an authentic image. After embedding the authentication signal, image is encry pted. If still Content modifications of the stego-image is detected, then data is repaired at the pixel level using reverse secrete s haring scheme. In case if the alpha channel is com pletely removed from the stegoimage, the integral resulting image is regarded as unauthentic, meaning that the integrity check of th e image fails. The proposed method is based on the generation of (k, n)-thresho ld secret sharing scheme proposed by Shamir. In thi s method a secret message is converted into n shares which is used as authentica tion signal for keeping by n participants; and when k of the n shares are collected, the secret image can be recovered without any loss[ 8]. This type of secret sharing scheme is helpful fthe risk of incidental partial data loss.