Showing papers on "Alpha compositing published in 2016"

Uber-in-light: Unobtrusive visible light communication leveraging complementary color channel

Abstract: Recently, Visible Light Communication (VLC) over a screen-camera channel has drawn considerable attention to unobtrusive design. It overcomes the distractive nature of traditional coded image approaches (e.g., barcodes). Previous unobtrusive methods fall into two categories: 1) utilizing alpha channel, a well known concept in computer graphics, to encode bits into the pixel translucency change with off-the-shelf smart devices; and 2) leveraging the spatial-temporal flicker-fusion property of human vision system with the fast frame rate of modern displays. However, these approaches heavily rely on high-end devices to achieve both unobtrusive and high accuracy screen-camera-based data communication without affecting video-viewing experience. Unlike previous approaches, we propose Uber-in-light, a novel unobtrusive and accurate VLC system, that enables real-time screen-camera communication, applicable to any screen and camera. The proposed system encodes the data as complementary intensity changes over Red, Green, and Blue (RGB) color channels that could be successfully decoded by camera while leaving the human visual perception unaffected. We design a MFSK modulation scheme with dedicated frame synchronization signal embedded in an orthogonal color channel to achieve high throughput. Furthermore, together with the complementary color intensity, an enhanced MUSIC-based demodulation scheme is developed to ensure highly accurate data transmission. Our user experience experiments confirmed the effectiveness of delivering unobtrusive data across different types of video content and resolutions. Extensive real-time performance evaluations are conducted using our prototype implementation to demonstrate the efficiency and reliability of the proposed system under diverse wireless environments.

ZoeMatrope: a system for physical material design

Abstract: Reality is the most realistic representation. We introduce a material display called ZoeMatrope that can reproduce a variety of materials with high resolution, dynamic range and light field reproducibility by using compositing and animation principles used in a zoetrope and a thaumatrope. With ZoeMatrope, the quality of the material is equivalent to that of real objects and the range of expressible materials is diversified by overlaying a set of base materials in a linear combination. ZoeMatrope is also able to express spatially-varying materials, and even augmented materials such as materials with an alpha channel. In this paper, we propose a method for selecting the optimal material set and determining the weights of the linear combination to reproduce a wide range of target materials properly. We also demonstrate the effectiveness of this approach with the developed system and show the results for various materials.

Uber-in-light: Unobtrusive visible light communication leveraging complementary color channel

Abstract: Recently, Visible Light Communication (VLC) over a screen-camera channel has drawn considerable attention to unobtrusive design. It overcomes the distractive nature of traditional coded image approaches (e.g., barcodes). Previous unobtrusive methods fall into two categories: 1) utilizing alpha channel, a well known concept in computer graphics, to encode bits into the pixel translucency change with off-the-shelf smart devices; and 2) leveraging the spatial-temporal flicker-fusion property of human vision system with the fast frame rate of modern displays. However, these approaches heavily rely on high-end devices to achieve both unobtrusive and high accuracy screen-camera-based data communication without affecting video-viewing experience. Unlike previous approaches, we propose Uber-in-light, a novel unobtrusive and accurate VLC system, that enables real-time screen-camera communication, applicable to any screen and camera. The proposed system encodes the data as complementary intensity changes over Red, Green, and Blue (RGB) color channels that could be successfully decoded by camera while leaving the human visual perception unaffected. We design a MFSK modulation scheme with dedicated frame synchronization signal embedded in an orthogonal color channel to achieve high throughput. Furthermore, together with the complementary color intensity, an enhanced MUSIC-based demodulation scheme is developed to ensure highly accurate data transmission. Our user experience experiments confirmed the effectiveness of delivering unobtrusive data across different types of video content and resolutions. Extensive real-time performance evaluations are conducted using our prototype implementation to demonstrate the efficiency and reliability of the proposed system under diverse wireless environments.

Stochastic layered alpha blending

Abstract: Researchers have long sought efficient techniques for order-independent transparency (OIT) in a rasterization pipeline, to avoid sorting geometry prior to render. Techniques like A-buffers, k-buffers, stochastic transparency, hybrid transparency, adaptive transparency, and multi-layer alpha blending all approach the problem slightly differently with different tradeoffs. These OIT algorithms have many similarities, and our investigations allowed us to construct a continuum on which they lie. During this categorization, we identified various new algorithms including stochastic layered alpha blending (SLAB), which combines stochastic transparency's consistent and (optionally) unbiased convergence with the smaller memory footprint of k-buffers. Our approach can be seen as a stratified sampling technique for stochastic transparency, generating quality better than 32 x samples per pixel for roughly the cost and memory of 8 x stochastic samples. As with stochastic transparency, we can exchange noise for added bias; our algorithm provides an explicit parameter to trade noise for bias. At one end, this parameter gives results identical to stochastic transparency. On the other end, the results are identical to k-buffering.

Apparatus and method for compressing autmented-reality video having alpha channel

Abstract: Disclosed are an apparatus and method for compressing a video including an alpha channel According to an embodiment of the present invention, the apparatus for compressing the video comprises: an image separation unit for separating each frame of a video including an alpha channel into a red, green, and blue (RGB) image and an alpha image; a gray scale image generation unit for generating a gray scale image from the separated alpha image; an image composition unit for generating a composed image in which the RGB image and the gray scale image are combined in parallel by each frame; and a compression unit for compressing the composed image by using a video compression algorithm

Background replacing method and apparatus for images

Abstract: The invention provides a background replacing method and apparatus for images. The background replacing method for images includes the steps: based on the RGB component of the current frame of an image, calculating a green difference value, and based on the green difference value, obtaining an initial alpha channel image which includes an initial background image and an initial foreground image; utilizing the green difference value to softening the initial alpha channel image to obtain a first alpha channel image; based on an ambient light factor, performing ambient light removing processing on the first alpha channel image to obtain a final alpha channel image which includes a background image to be synthesized and a processed foreground image; and synthesizing the final alpha channel image, the background image to be synthesized and the processed foreground image. The background replacing method and apparatus for images can modify an existing scheme based on green screen sectional drawing and increases softening and ambient light removing processing so that images can become more softened and natural.

Robust image authentication scheme with self-repair capability for greyscale source document images via PNG format

Abstract: Recently, Lee and Tsai proposed a new authentication method for greyscale document images using the portable network graphics format image; however, their method cannot resist the self-substitution attack, the same-position-substitution attack, or the cut-off attack. Furthermore, those attacks can be completed by the popular image editing software Adobe Photoshop. Therefore, the authors proposed a security-enhanced authentication scheme based on Lee and Tsai's method. The authors’ proposed scheme uses three random binary sequences to randomise the binary version of a given greyscale document image, and thus overcomes the security flaws mentioned above. The authors’ proposed scheme is capable of repairing the content of the given stego-image if attacked by the methods mentioned above. Moreover, the authors’ proposed scheme retains all of the strengths of Lee and Tsai's scheme. The authors improve the opacity of the alpha channel of stego-image by using Wang and Su's extended secret sharing, and enhance the data security by using Hash functions. The experimental results show that the authors’ proposed scheme is effective for application.

View-Aware Image Object Compositing and Synthesis from Multiple Sources

Abstract: Image compositing is widely used to combine visual elements from separate source images into a single image. Although recent image compositing techniques are capable of achieving smooth blending of the visual elements from different sources, most of them implicitly assume the source images are taken in the same viewpoint. In this paper, we present an approach to compositing novel image objects from multiple source images which have different viewpoints. Our key idea is to construct 3D proxies for meaningful components of the source image objects, and use these 3D component proxies to warp and seamlessly merge components together in the same viewpoint. To realize this idea, we introduce a coordinate-frame based single-view camera calibration algorithm to handle general types of image objects, a structure-aware cuboid optimization algorithm to get the cuboid proxies for image object components with correct structure relationship, and finally a 3D-proxy transformation guided image warping algorithm to stitch object components. We further describe a novel application based on this compositing approach to automatically synthesize a large number of image objects from a set of exemplars. Experimental results show that our compositing approach can be applied to a variety of image objects, such as chairs, cups, lamps, and robots, and the synthesis application can create novel image objects with significant shape and style variations from a small set of exemplars.

Continuous depth-ordered image compositing

Abstract: A system creates an output image of a scene using two-dimensional (2D) images of the scene. For a pixel in the output image, the system identifies, in the output image, 2D fragments that correspond to the pixel. The system converts the 2D fragments into three dimensional (3D) fragments, creates volume spans for the pixel based on the 3D fragments, determines a color of a volume span based on color contribution of respective one or more of the 3D fragments for the volume span, and determines a color of the pixel for the output image from determined colors of the volume spans.

Method for processing plane figure image

Abstract: The invention discloses a method for processing a plane figure image. The method comprises the following steps: extracting feature points from image edges after an image is preprocessed, then based on the feature points extracted from the image edges, reconstructing an accurate surface model; conducting accurate registration on the surface model and a series of color photos photographed of an object so as to obtain a 3D model; in accordance with RGB data and alpha channel data of the acquired 3D model, generating PNG format data of the 3D model, and extracting the RGB data and the alpha channel data of the 3D model, and generating BMP format to be inserted to a video; based on the acquired PNG format data of the 3D model, in accordance with a determined switching moment, generating an animation with background music and background pictures. According to the invention, the method can convert images to dynamic 3D models, then combines background music, background picture, and 3D effects in a perfect manner, and provides vivid sense of immersion for users.

Device and method for producing augmented reality image by using chroma key

Abstract: A device and method for producing an augmented reality image by using a chroma key are disclosed. The device for producing an augmented reality image by using the chroma key generates an augmented reality content image including an alpha channel before synthesizing a content image including a virtual object in a live image, synthesizes the live image in the previously generated augmented reality content image, and outputs the synthesized image. Therefore, a synchronization problem due to alpha channel synthesis can be solved.

An Efficient Fingerprint Watermarking Approach Using 3 Levels DWT and Alpha Blending Technique

Abstract: In recent years of internet has been increased with the extensive growth in the digital technique Digital watermarking technique is used to provide security This paper proposes the watermarking based on 3 level discrete wavelet transform and alpha blending technique A multibit watermarking technique is used into low frequency sub band of cover image by using alpha blending technique by varying the scaling factor The extraction of the watermark is also done by the scaling factor To enhance the security a key is used at both sender and receiver side The PSNR (peak signal to noise ratio) and MSE (mean square error) values are obtained for different values of scaling factor alpha Watermark generated by the proposed algorithm is more robust to attacks and the quality of the recovered image is improved

OpenEXR/Id isolate any object with a perfect antialiasing

Abstract: We present a new storage scheme for computer graphic images based on OpenEXR 2. Using such EXR/Id files, the compositing artist can isolate an object selection (by picking them or using a regular expression to match their names) and color corrects them with no edge artefact, which was not possible to achieve without rendering the object selection on its own layer. Using this file format avoids going back and forth between the rendering and the compositing departments because no mask image or layering are needed anymore. The technique is demonstrated in an open source software suite, including a library to read and write the EXR/Id files and an OpenFX plug-in which generates the images in any compositing software.

Digital Makeup from Internet Images

Abstract: We present a novel approach of color transfer between images by exploring their high-level semantic information. First, we set up a database which consists of the collection of downloaded images from the internet, which are segmented automatically by using matting techniques. We then, extract image foregrounds from both source and multiple target images. Then by using image matting algorithms, the system extracts the semantic information such as faces, lips, teeth, eyes, eyebrows, etc., from the extracted foregrounds of the source image. And, then the color is transferred between corresponding parts with the same semantic information. Next we get the color transferred result by seamlessly compositing different parts together using alpha blending. In the final step, we present an efficient method of color consistency to optimize the color of a collection of images showing the common scene. The main advantage of our method over existing techniques is that it does not need face matching, as one could use more than one target images. It is not restricted to head shot images as we can also change the color style in the wild. Moreover, our algorithm does not require to choose the same color style, same pose and image size between source and target images. Our algorithm is not restricted to one-to-one image color transfer and can make use of more than one target images to transfer the color in different parts in the source image. Comparing with other approaches, our algorithm is much better in color blending in the input data.

New High Capacity Secure Steganography Technique

Abstract: With the spread of digital data around the world through the internet, the security of the data has raised a concern to the people. Many methods are coming up to protect the data from going into the hands of the unauthorized person. Steganography and cryptography are two different techniques for data security . The main purpose in cryptography is to make message concept unintelligible, while steganography aims to hide secret message. Digital images are excellent carriers of hidden information. In this paper a new steganography approach proposed based on LSB technique by using Alpha channel on JPG cover images and Bit-slicing decomposition and AES ( Advanced Encryption Standard) on the secrete image. for this method first the secrete image decomposed to bit streams and the data encrypted using AES algorithm. On the cover side, an alpha channel is attached to the cover image and the data embedded into LSBs of RGBA channels. The method was implemented and tested by using MATLAB® (R2011a).

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.

Image forming apparatus, image forming method, and program

Abstract: PROBLEM TO BE SOLVED: To solve the problem in which: alpha blending can be omitted in drawing of image data only when the image data is constituted with completely transparent pixels or completely opaque pixels.SOLUTION: An image processing apparatus does not perform alpha blending to pixels having a specific alpha value of image data, and performs alpha blending to pixels having an alpha value different from the specific alpha value.SELECTED DRAWING: Figure 5

Alpha Channel base Data Hiding using Compressive Sensing

Abstract: In recent day image ownership authentication has drawn a sharp attention due to easy availability of the internet and inexpensive digital recording and storage peripherals has created an environment where duplication, unauthorized use, and distribution of the digital content has become easier that leads cybercrime. Due to the wide distribution and usage of digital media, an important issue is protection of the digital content.There is a number of algorithms and techniques developed for the digital watermarking. Today already proposed different color image watermarking frameworks for embedding a color watermark within a color input image. An input image is divided into some blocks. In proposed technique use embed watermark at two LSBs in alpha channel of all such blocks. Although alpha channel is used for controlling the transparency of the image, but two LSB's in the alpha channel are unused bits. In this technique we have used these two bits for embedding information. They don’t have any contribution in luminance and chrominance factor. For that reason watermark is fully invisible to the Human Visual System (HVS) and no bits are changed in the RGB channel of the input image and for that reason no color information of the input image have been lost. So the color density of the original and watermarked image is same. Use the compressive sensing (CS) method that provides reconstruction of the signal/image. CS can provide good quality of image reconstruction with smaller number of samples and at the same time to detect and extract the watermark. At the extraction end quality of input image and watermark is same as it is.

Display apparatus, controlling method thereof and data transmitting method thereof

Abstract: The present invention provides a display apparatus and a control method thereof. According to one embodiment of the present invention, the display apparatus includes: an input unit receiving a display signal including a video signal, a graphic signal, and an alpha value; a calculation unit calculating effective data of the video signal and the graphic signal to perform alpha blending by using an alpha value of each pixel in the display signal; an alpha blending unit performing alpha blending for a display signal by using the effective data calculated through the calculation unit and the alpha value; and a display unit displaying an image generated according to the alpha blended display signal.

Apparatus and method for making augmented reality video used chromakey

Abstract: Disclosed are an apparatus and a method for making an augmented reality image using chromakey. The apparatus for making an augmented reality image using chromakey: generates a content image for augmented reality including an alpha channel before composing a content image including a virtual object to a live image; and composes the live image to the previously generated content image for augmented reality to output the same, thereby solving a synchronization problem caused by alpha channel composition.