Showing papers on "Alpha compositing published in 2012"

Image Watermarking Using 3-Level Discrete Wavelet Transform (DWT)

Abstract: We have implemented a robust image watermarking technique for the copyright protection based on 3-level discrete wavelet transform (DWT). In this technique a multi-bit watermark is embedded into the low frequency sub-band of a cover image by using alpha blending technique. The insertion and extraction of the watermark in the grayscale cover image is found to be simpler than other transform techniques. The proposed method is compared with the 1-level and 2-level DWT based image watermarking methods by using statistical parameters such as peak-signal-to-noise-ratio (PSNR) and mean square error (MSE). The experimental results demonstrate that the watermarks generated with the proposed algorithm are invisible and the quality of watermarked image and the recovered image are improved.

A modified secure digital image steganography based on Discrete Wavelet Transform

Abstract: Steganography, the secret image is embedded in the cover image and transmitted in such a way that the existence of information is undetectable. The digital images, videos, sound files and other computer files can be used as carrier to embed the information. In this paper, we propose a modified secure and high capacity based steganography scheme of hiding a large-size secret image into a small-size cover image. Arnold transformation is performed to scrambles the secret image. Discrete Wavelet Transform (DWT) is performed in both images and followed by Alpha blending operation. Then the Inverse Discrete Wavelet Transformation (IDWT) is applied to get the stego image. We have investigated the performance of our scheme by comparing various qualities of the stego image and cover image. The results show that the proposed algorithm for modified steganography is highly secured with certain strength in addition to good perceptual invisibility.

A Novel Approach of Color Image Hiding using RGB Color planes and DWT

Abstract: This work proposes a wavelet based Steganographic technique for the color image. The true color cover image and the true color secret image both are decomposed into three separate color planes namely R, G and B. Each plane of the images is decomposed into four sub bands using DWT. Each color plane of the secret image is hidden by alpha blending technique in the corresponding sub bands of the respective color planes of the original image. During embedding, secret image is dispersed within the original image depending upon the alpha value. Extraction of the secret image varies according to the alpha value. In this approach the stego image generated is of acceptable level of imperceptibility and distortion compared to the cover image and the overall security is high.

Dynamic range extension by combining differently exposed hand-held device-acquired images

Abstract: Two or more digital images of a same scene are captured with different exposure levels. Image pairs are generated that have a same exposure level from the image data of differently exposed images by adjusting the exposure of at least one of the pair of images. A ghosting map is generated based on differences between the pair of images adjusted to the same exposure. A blurred ghosting map is generated and alpha blending is performed.

A Novel Approach of Color Image Hiding using RGB Color planes and DWT

Abstract: This work proposes a wavelet based Steganographic technique for the color image. The true color cover image and the true color secret image both are decomposed into three separate color planes namely R, G and B. Each plane of the images is decomposed into four sub bands using DWT. Each color plane of the secret image is hidden by alpha blending technique in the corresponding sub bands of the respective color planes of the original image. During embedding, secret image is dispersed within the original image depending upon the alpha value. Extraction of the secret image varies according to the alpha value. In this approach the stego image generated is of acceptable level of imperceptibility and distortion compared to the cover image and the overall security is high.

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.

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.

Depth image based compositing for stereo 3D

Abstract: Compositing is an essential tool in modern film making. Established workflows exist for single-view video compositing, however new problems that demand new solutions arise when considering stereoscopic compositing. We investigate new methods for compositing live action stereo 3D, given two stereo camera systems and a corresponding depth map. We break the process up into three main steps; First, we show how to use trifocal tensors to robustly project 3D content from one video into another. Second, we analyze different image-based rendering methods for drawing objects to be composited into the new video. Finally, we describe a novel super-pixel based depth-test that increases robustness to errors in depth map accuracy. A user study was conducted to validate different steps of this process.

Mixed-order compositing for images having three-dimensional painting effects

Abstract: Rendering 3D paintings can be done by compositing brush strokes embedded in space. Image elements are rendered into an image representable by a pixel array wherein at least some of the image elements correspond to simulated painting strokes. A method may include determining stroke positions in a 3D space, determining stroke orders, and for each pixel to be addressed, determining a pixel color value by determining strokes intersections with a view ray for that pixel, determining a depth order and a stroke order for intersecting fragments, each fragment having a color, alpha value, depth, and stroke order, assigning an intermediate color to each of the fragments, corresponding to a compositing of nearby fragments in stroke order, and assigning a color to the pixel that corresponds to a compositing of the fragments using the intermediate colors assigned to the fragments. The compositing may be done in depth order.

A new invisible color image watermarking framework through alpha channel

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 maldistribution of the digital content has become easier that leads cyber crime. In aforesaid regard we've already proposed different fragile color image watermarking frameworks for embedding a color watermark within a color host image. The host image is simply divided into some blocks so that as per our proposed technique we are able to 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 scheme we have used these two bits for embedding information. They do not have any contribution in luminance and chrominance factor. For that reason watermark is fully invisible to the Human Visual System and no bits are changed in the red, green, and blue channel of the host image and for that reason no color information of the host image have been lost. So the color density of the original and watermarked image is same. In proposed watermarking framework, it allows a user with an appropriate secret key and a hash function to verify the authencity, integrity and ownership of an image. If a forger performs the watermark extraction with an incorrect key and inappropriate hash function, the user obtains an image that resembles noise. In this manner we are providing an integrated solution for ownership authentication where the watermark is unique for that particular host image, thus the authentication is ensured in an efficient way. At the watermark extraction end, we've used blind extraction method, i.e., neither the host image nor the watermark image is required at the time of watermark extraction.

An image synthesis method and system using alpha channel

Abstract: The invention discloses an image synthesis method and system using alpha channels. The image synthesis method comprises the following steps: according to an alpha channel of a foreground image and an alpha channel of a background image, sequentially calculating the alpha value of each pixel of a synthesized image through a preset matrix A; according to the alpha channel of the foreground image, the alpha channel of the background image, a color channel of the foreground image and a color channel of the background image, sequentially calculating the color value of each pixel of the synthesizedimage through a preset matrix S; and according to the calculated alpha value and color value of each pixel of the synthesized image, obtaining the synthesized image. The invention also discloses an image synthesis system by using alpha channels. Through implementing the technical scheme of the invention, the information of the synthesized image can simultaneously contain the information of the alpha channels of two images before being synthesized.

A new lossless visible watermarking method via the use of the PNG image

Abstract: A new lossless visible watermarking method via the use of the PNG image is proposed. The method transforms a color host image into the PNG format with an additional alpha channel plane and a visible watermark is then embedded into the color channel plane of the host image. During the embedding process, data of color pixels covered by the watermark are collected to form a data packet. The data packet is then embedded into the alpha channel plane in order to remove the visible watermark from the watermarked image later. Furthermore, pixel values in the alpha channel plane are mapped into a range near their maximum value of 255 to yield a nearly total transparent watermarked image. During the process of image recovery, the proposed method can remove the visible watermark from the watermarked image without the original watermark because all data that are needed to losslessly recover the watermarked image are embedded in the alpha channel plane. Experimental results demonstrating the effectiveness of the proposed method are also included.

Animated visualization of alpha channel transparency

Abstract: Visual inspection of alpha channel values is aided by displaying a partially transparent image rendered over an animated background pattern. The background pattern is user-specified or chosen automatically. The background pattern has colors, shapes, position, orientation, magnification, and distortion. The visual appearance of the background pattern is automatically altered, and the partially transparent image is redisplayed, this time rendered over the altered background pattern. The background pattern may scroll, rotate, change shape, pulse, morph shape, and/or change colors during animation. The background includes a checkerboard or another tessellation, a color gradient, a transparency heat map, a procedurally generated texture, and/or other patterns. A color identified in the partially transparent image may provoke use of a complementary color in the background. The image whose transparency is being visually inspected zooms independently of the background pattern. Animation of the background helps reveal unwanted transparency values, which the user edits as desired.

Enhancement of Depth Maps With Alpha Channel Estimation for 3-D Video

Abstract: Depth images are widely used for 3-D scene generation. In depth image acquisition, accurate estimation of the depths of object boundaries, which has a critical impact on the visual quality of the generated 3-D scene, is very difficult, especially in the case of objects with a hairy region. We aimed to generate a dynamic 3-D scene without serious degradation in visual quality by developing solutions for the problems that occur in depth images obtained using an active depth sensor. A novel alpha channel estimation algorithm is proposed for seamless composition along with a depth map improvement method for hairy objects. By utilizing additional depth or infrared (IR) information, the existing matting algorithm can be improved significantly. We further enhanced the alpha estimation method in the temporal domain. The depth map was enhanced by filtering depth values along spatiotemporal neighborhoods based on information provided by the color and alpha images. The proposed method was examined mainly using a time-of-flight (TOF) camera, and Kinect is used too. The experimental results demonstrated that the proposed method can generate a 3-D scene with a greater degree of naturalness as compared to other methods.

Transparency information in image or video format not natively supporting transparency

Abstract: Colour information and transparency information of pixels of a source image, which may be a partially transparent overlay image of a format that natively support transparency, are stored as a transformed image. The transformed image is of a format that does not natively support transparency. The transformed image has two disjoint regions, one storing the source color information and the other storing the source transparency information. The transformed image can be used as a representation of the overlay image when compositing with a base image.

Image generation device, image generation system, image display device, computer program, and image generation method

Abstract: PROBLEM TO BE SOLVED: To provide an image generation device, an image generation system, an image display device, a computer program, and an image generation method capable of composing an original image and a filter image looking like a paper medium by alpha blending processing so as to achieve appearance like a paper medium.SOLUTION: A composite image generation unit 14 generates a composite image in which an input image and a filter image are composed by an arbitrary fraction. A gradation range calculation unit 131 calculates a gradation width (such as maximum gradation and minimum gradation) of the composite image. A control unit 13 controls gradation conversion processing by changing a predetermined condition of an LUT conversion unit 15 on the basis of the calculated gradation width.

Texture Compression with Variable Data Formats

Abstract: Texture compression is an important technique widely adopted in graphics processing units (GPUs) nowadays to reduce memory bandwidth consumption. However, modern texture compression schemes cannot generate satisfactory visual qualities for both alpha channel and color channel of texture images. In this paper we present a novel texture compression scheme, called CATC (Complexity-Aware Texture Compression), based on the insight into the essential differences between transparency and color. CATC defines new texture compression data formats and compresses the alpha channel and color channel of texture image flexibly. CATC employs clustering algorithm combined with the linear interpolation method to compress the alpha channel of texture images. If the alpha values are of low complexity, CATC takes advantage of the free bits in compressed block of alpha channel to compress color channel of texture image. While keeping the same compression ratio as the de facto standard texture compression scheme, CATC improves both the two channels' compression quality. The average PSNR score of alpha channel is improved by about 0.2 dB, and the average PSNR score of color channel can be increased by up to 7.17 dB over a set of test images, which makes CATC a better substitute for the standard texture compression scheme.

Method for realizing unlimited blue-box function used in virtual studio systems

Abstract: The invention relates to a television-program producing-broadcasting technique in the field of radio and television, in particular to a method for realizing unlimited blue-box function used in virtual studio systems. The method is characterized in that surface sheet structures are generated in a complementary-set region of a blue box to form a geometric body; each surface of the geometric body isa plane; every plane is taken as a mask; filled signals are background signals; when a camera is swung out of a blue-box region, the planes taken as masks are rendered in an Alpha cache; meanwhile, according to foreground, background and occlusion relation, three-dimensional objects used to occlude the foreground are extracted to be rendered in the Alpha cache; rendered images are synthesized to be video signals output to a color key through an Alpha channel; and the color key serving as a foreign key is synthesized with the background and the foreground in real time to generate video images reflecting three-dimensional effects. The method during application can fine adjust the size of blue boxes in order to be matched with different size of the blue boxes to realize final occlusion effects, thereby perfectly fusing the foreground with the background.

Encoding, transmitting and displaying a sequence of images using a difference image

Abstract: The present invention relates to encoding, transmitting and displaying a sequence of images in which a difference image indicative of the difference between an image of the sequence and a subsequent image of the sequence to be displayed is generated such that, when it is overlaid onto the image, the composite image and the difference image is identical to the subsequent image. The difference image may be generated by comparing a pixel subset of the subsequent image to corresponding pixels in the previous image, and setting the pixel as transparent if it is identical and passes a similarity test, and setting the pixel as opaque if it fails the test. A difference image may be combined with an adjacent difference image to form a composite difference image. A thin client (web browser) may receive the images using a networking protocol. The image overlaying may be based on alpha channel transparency or index based transparency to aid video compression.

Information processing apparatus, information processing method, and computer readable recording medium for print control

Abstract: An information processing apparatus includes a drawing receiving unit to receive a page start command and a drawing command from an OS, a transparency processing unit to generate a bitmap upon receiving the page start command, to alpha blend a first image with a second image existing on the bitmap to generate a blended image upon receiving the drawing command that includes the first image with an alpha channel, and to duplicate the alpha blended image, and a drawing processing unit to convert the drawing command that includes the first image with the alpha channel, into a print command to draw the duplicated alpha blended image

Image fusion method based on Alpha channel bitmap technology

Abstract: The invention discloses an image fusion method based on an Alpha channel bitmap technology. More particularly, the invention, which belongs to the image processing technology field, discloses a multi-mode medial image fusion method based on an Alpha channel bitmap technology. The method comprises the following steps that: (1), source images that need to be fused are input; (2), a weight K is obtained; (3), color stretching is carried out on the source images; (4), s bitmap coding method is utilized to carry out processing on the stretched images as well as a pseudo color disk is loaded; and (5), an Alpha channel is used to carry out weight fusion so as to generate an image after the fusion. According to the invention, improvement that is aiming at two traditional fusion methods is carried out; it can be ensured that an image is clear and meanwhile, a pseudo color disk can be rapidly loaded, so that it is convenient to adjust weights of two parties of fusion. Moreover, the method is simple and can be used conveniently and flexibly as well as is suitable for rapid adjustment and display in clinic practice.

Multi-type sensor information real-time display method by software based on commercial graphic card

Abstract: The invention relates to a multi-type sensor information real-time display method by software based on a software 3D (three-dimensional) game view angle picture display mode, which mainly uses the direct 3D multimedia development technique. The method includes: firstly, using a programmable pipeline way (GPU (graphic processing unit) rendering) to give full play of GPU functions and realize great improvement of display efficiency by the aid of high efficiency of direct 3D; and secondly, using direct 3D to process flexibility of pictures, on the one hand, using a 3D game view angle picture display mode to realize display of special effects such as eccentric display, zooming display, superposition of background maps, roaming and the like by continuously adjusting world coordinates and viewpoint coordinates in 3D scenes, and on the other side, using a video image alpha channel mixing way to realize afterglow display of radar video. The method has the advantages of high programming flexibility, high instantaneity, low cost, easiness in implementation and the like based on a commercial computer framework.

Authentication of Document Image with Data Repairing

Abstract: 1,2 RCET, Bhilai Abstract: In this paper, we are introducing a blind authentication method which is based on the secret sharing technique with a data repair capability for document images with the use of the PNG image. We generate an authentication signal for each block of a document image which, together with the block content in binary form, is transformed into several shares using the Shamir secret sharing scheme. These parameters are carefully chosen so that a large number of shares possible are generated and embedded into an alpha channel plane. Now the alpha channel plane is combined with the original image to form a PNG image. In the process of image authentication, an image block is marked as tampered if the authentication signal computed from the current block content does not match the one extracted from the shares embedded in the alpha channel plane. Repairing of data is now done to each tampered block by a reverse Shamir technique after collecting any two or more shares from unmarked blocks. Also a measure to protect the security of the data hidden in the alpha channel is proposed.

Alpha compositing method

Abstract: An alpha compositing method adapted to a plurality of compositing layers and a background layer including the following steps is provided. Firstly, alpha channel data and RGB channel data of the compositing layer and RGB channel data of the background layer are obtained. Next, a merging alpha channel data is calculated according to the alpha channel data of the composting layers. Then, a merging RGB channel data is calculated according to the merging alpha channel data and the RGB channel data of the compositing layers. Afterwards, the RGB channel of the background is preceded to a background compositing calculation with the merging alpha channel data and the merging RGB channel data to generate an output RGB channel data of the background layer.