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.

Picture compression method keeping with alpha channel

Abstract: The invention relates to a picture compression method keeping with an alpha channel. The picture compression method comprises the following steps: 1) reading picture data, scanning picture data pixel by pixel, and separating alpha channel data of each pixel; 2) combining alpha channel data of all pixels to be an alpha channel file; 3) carrying out a lossy compression on RGB (red green blue) channel data of all pixels to generate a RGB compressed file; and 4) combining the alpha channel file with the RGB compressed file in an intermediate file, and carrying out lossless compression on the intermediate file to generate compressed data. After the compression for twice, completed alpha channel file through the lossless compression and the RGB compressed file with lower compression rate through the lossy compression are kept in the compressed data, so that the alpha channel data of the picture file with ARGB (alpha red green blue) channel data can be kept, the compression rate of the picture file can be increased, and furthermore, the compression method can be used for encrypting the picture file.

A Physically Based Colour Model

Abstract: We propose an intuitively simple way of representing colour which has the additional virtue that, it permits mixing and overlaying of transparent and opaque paints to an arbitrary degree. Our approach is related to the earlier alpha channel model used for compositing. It includes this as a special case but has applications in many other areas, especially animation, paint programs and graphics libraries.

Image fusion method for panoramic parking system

Abstract: The invention discloses an image fusion method for a panoramic parking system, which is an image processing method applied to an automobile electronic field and an automobile safety assistant driving field. The image fusion method comprises the following steps of: obtaining the coordinate of a pixel point in a superposition area, calculating an included angle formed by the pixel point and a boundary line of the superposition area, calculating alpha channel values of two images at the pixel point and fusing images of the superposition area. According to the image fusion method disclosed by the invention, the aerial-view of the superposition area can be fused into a whole body, a problem that an obvious splicing trace exists in a superposition sampling area is solved, and internal images in the superposition area are in natural and smooth transition so that user experience of the panoramic parking system is increased. The image fusion method disclosed by the invention utilizes a mathematical model in accordance with the change rule of an actual problem, has the advantages of very small calculation amount, high processing speed and strong expandability and is suitable for large-scale popularization and application.

RGB channel based decision tree grey-alpha medical image steganography with RSA cryptosystem

Abstract: This paper presents the novelty in sensitive data transmission of patient medical records. The secret medical data is hidden inside scanned grey medical image or magnetic resonance image using the red, green, blue, and alpha (RGBA) image and with the help of decision tree. In this technique, alpha channel will be separated from the RGBA image and merged to the medical grey image to improve the hiding capacity. RSA cryptosystem is used to encrypt the medical data, and divided into various blocks using dynamic key. In steganography process, organize the grey-alpha channel medical cover image into various blocks using dynamic key. Secret cipher blocks are assigned to grey-alpha channel medical cover image blocks using Breadth First Search and decision tree, for data embedding. Performance analysis is observed using various performance measure parameters between various medical stego and cover images.

DWT based color image watermarking using maximum entropy

Abstract: Digital watermarking techniques can be used to solve the authenticity and copyright protection issue of images. In this work, the authors have proposed an adaptive color image watermarking scheme based on DWT by combining alpha blending and entropy concept. Entropy is one of the important features of images and can be used for watermark insertion. There are two domains in which watermarking can be carried out i.e. spatial and transform domain. Here, watermark embedding is carried out in the of Y component of YCbCr color space. This paper also lays down the proper justification for the selection of the Y component to embed the watermark. The performance of the proposed scheme is tested over seven different standard color images. The average PSNR and SSIM of the proposed scheme are 51.6145 dB and 0.9992 respectively. Whereas, NCC of the proposed scheme under no attack condition is 1. Further, the performance of the proposed scheme is compared with other state-of-the-art techniques.