Showing papers on "Channel (digital image) published in 1997"

Digital signature of color images using amplitude modulation

Abstract: Watermarking techniques, also referred to as digital signature, sign images by introducing changes that are imperceptible to the human eye but easily recoverable by a computer program. Generally, the signature is a number which identifies the owner of the image. The locations in the image where the signature is embedded are determined by a secret key. Doing so prevents possible pirates from easily removing the signature. Furthermore, it should be possible to retrieve the signature from an altered image. Possible alternations of signed images include blurring, compression and geometrical transformations such as rotation and translation. These alterations are referred to as attacks. A new method based on amplitude modulation is presented. Single signature bits are multiply embedded by modifying pixel values in the blue channel. These modifications are either additive or subtractive, depending on the value of the bit, and proportional to the luminance. This new method has shown to be resistant to both classical attacks, such as filtering, and geometrical attacks. Moreover, the signature can be extracted without the original image.

Apparatus and a method for reducing red-eye in a digital image

Abstract: A red-eye reduction system is described that includes a masking module. The masking module converts an image into a mask having first state areas representing red color pixels of the image and second state areas representing other color pixels of the image. The image includes an eye with a red pupil. A pupil locating module is coupled to the masking module to locate a substantially first state area in the mask that resembles a pupil. A color replacing module is then coupled to the pupil locating module to change the red color pixels in the area into monochrome (grey) or other predefined colors. The color replacing module also adjusts the boundary of the area by changing the colors of pixels in close proximity to the area if the color of these pixels is determined to be sufficiently close to red such that natural appearance of the eye is maintained when reducing the red pupil. A method of reducing red-eye effect in a digital image is also described.

Blind channel estimation using the second-order statistics: algorithms

Abstract: Most second-order moment-based blind channel estimators belong to two categories: (i) optimal correlation/spectral fitting techniques and (ii) eigenstructure-based techniques. These two classes of algorithms have complementary advantages and disadvantages. A new optimization criterion referred to as the joint optimization with subspace constraints (JOSC) is proposed to unify the two types of approaches. Based on this criterion, a new algorithm is developed to combine the strength of the two classes of blind channel estimators. Among a number of attractive features, the JOSC algorithm does not require the accurate detection of the channel order. When compared with existing eigenstructure-based techniques, the JOSC performs better, especially when the channel is close to being unidentifiable. When compared with correlation/spectral fitting schemes, the JOSC is less affected by the presence of local minima.

Digital composition of a mosaic image

Abstract: A mosaic image is formed from a database of source images. More particularly, the source images are analyzed, selected and organized to produce the mosaic image. A target image is divided into tile regions, each of which is compared with individual source image portions to determine the best available matching source image by computing red, green and blue channel root-mean square error. The mosaic image is formed by positioning the respective best-matching source images at the respective tile regions.

Method and system for automatically calibrating a color camera in a machine vision system

Abstract: A machine vision system (20) color camera is calibrated via two algorithms. Separate red, green and blue image gray level histograms (44) in a calibration target (40) are utilized to generate corresponding standard cumulative probability functions (46). The probability functions and a target copy is provided to the system. Repeating the above steps (48) result in comparing cumulative probability functions are compared to corresponding standard cumulative probability functions (50) to obtain red, green and blue channel gains of the uncalibrated camera (52). In a second calibration algorithm, a target patch of pure white is observed (70, 72) while determining camera outputs for red, green and blue (74). The average gain for each output channel of the color camera is determined (76). The calculated average white level value for each channel is divided into the full scale value of the uncalibrated vision system. The three gain factors of either algorithm applied to a subsequent image yields a color-corrected image (52, 78).

Image reconstruction in a CT fluoroscopy system

Abstract: A CT Fluoro system having an architecture and algorithms which facilitate increasing the frame rate and providing acceptable image quality is described. Generally, and in one embodiment, the system includes apparatus and algorithms that speed-up image reconstruction and reduce image artifacts that may result from such fast reconstruction. The fast reconstruction is achieved by performing, for example, view compression, channel compression, backprojection with reduced delay, and parallel processing.

System and method for adjusting color data of pixels in a digital image

Abstract: Color data of pixels of a digital image are adjusted by identifying pixels of a digital image having original color data corresponding to predetermined color and shape characteristics and adjusting the original color data of the identified pixels to achieve a desired result.

Simultaneous multichannel image restoration and estimation of the regularization parameters

Abstract: In this correspondence, a constrained least-squares multichannel image restoration approach is proposed, in which no prior knowledge of the noise variance at each channel or the degree of smoothness of the original image is required. The regularization functional for each channel is determined by incorporating both within-channel and cross-channel information. It is shown that the proposed smoothing functional has a global minimizer.

Method and system for converting images in computer systems

Abstract: The present invention provides a method and system in computer systems for converting an original image into another image having fewer colors than the original image. This method and system attempt to preserve the contrast of the original image. As a result, this method and system are particularly well-suited for converting images that are relatively small in size. A computer system in which the present invention operates includes a computer connected to a display device and a secondary storage device. An image converter is stored in the secondary storage device for execution by the computer. In operation, the computer receives an original image to be displayed on the display device. The image converter converts the original image into another image having fewer colors than the original image. Lastly, the computer displays the converted image on the display device. In order to convert the original image, the image converter determines which pixels in the original image are opaque in the converted image. For the pixels that are opaque in the converted image, the image converter determines a gray-scale representation of the pixels. For the same pixels, the image converter then determines a black-and-white representation of the pixels. Next, the image converter determines the color assigned to the black pixels in the converted image and the color assigned to the white pixels in the converted image. Lastly, the image converter specifies the representation of the converted image.

Ray tube tracing method for predicting indoor channel characteristics map

Abstract: A novel adaptive ray tube tracing algorithm optimised for creating indoor radio channel characteristic maps is presented. The algorithm, based on the shooting-and-bouncing-ray with image method and an adaptive resolution control technique, shows a large improvement in computational efficiency compared to conventional methods.

A New Color Management System Based on Human Perception and its Application to Recording and Reproduction of Art Paintings.

Abstract: A new color management system has been developed for high definition color recording and reproduction of art paintings. This system is consisted of high accurate multiband camera, personal computer and projected type display. The multi-band camera is composed by five band filters and single chip CCD camera with 2048x2048 pixels. The reflectance spectra of each pixel of the object were estimated by using five band images within less than the average color difference ∆E*ab = 1.16. The spectral transmittance of five filters was determined by simulated annealing method and principal component analysis of spectral reflectance of paintings. Images of art paintings were reproduced onto the projection type monitor under the consideration of color appearance. In this paper, we describe methods to estimate of reflectance spectra of paintings from five band images, optimization of spectral transmittance of filters and color reproduction of paintings based on the color appearance models. Introduction In recent years, high accuracy digital color imaging system is required in artworks and medical imagings by the advent of information superhighway. In artworks, conventional photographic system has been used for image acquisition and recording. HDTV(High Definition Television) are also used for displaying the paintings, arts and crafts in several 16 Japanese museums. Photographic system, hybrid imaging system used film and scanner, and HDTV system only record the R,G,B three channel images, and they cannot record the reflection spectra of the objects. Reflection spectra is one of the most important information of the objects, and it is not dependent on the spectral radiant distribution of the taking light source. On the other hand, color reproduction of those imaging systems is based on the colorimetric color reproduction as to have same chromaticities between object and image. However, it should be considered the color reproduction based on the human perception such as color adaptation under the viewing condition in an art gallery or museum. We have developed the high accurate imaging systems which is consisted of image acquisition system used multiband CCD camera, color management system based on color adaptation model and estimation of reflection spectra of the objects, and display systems as shown in Figure 1. In the following sections, detail of the developed imaging systems is described. Multiband camera and the Estimation of Reflection Spectra In image acquisition, we used two high quality digital cameras; Fotex F-10 (2048x2048 pixels, 12 bits/pixel ) and Kodak DCS420m (1536x1024 pixels 12bits A/D, 8 bits output). Multiband images were captured by digital camera incorporating a rotating wheel comprising five color filters in front of camera lens. Gray scales with 16 steps and crop marks were recorded with object in each channel, and each channel image data was merged into single file.

Multicolor and mixed-mode halftoning

Abstract: A printer driver operates a printer capable of multiple dot-placement geometries or resolutions and multiple inks per color channel. It maps a continuous-tone cyan pixel-component value to continuous-tone light- and dark-cyan values, which it separately halftones to respective binary pixel values that respectively indicate whether an associated pixel will receive light- and dark-cyan ink dots. It similarly generates binary values that respectively indicate whether an associated pixel will receive light- and dark-magenta ink dots. In performing the halftoning, the driver separately performs error diffusion through different interleaved sub-images of the image to be printed so that the error-diffusion process is performed for images whose pixel geometry is that for which the process was designed even though the overall image's pixel geometry is not. The result is a modular, scaleable architecture, in which designs for one ink per channel and/or one dot-placement geometry can be adapted with minimal design effort to multiple inks and dot-placement geometries.

Digital photography device and method

Abstract: A combination of digital camera design and digital photography technique that allows a single digital camera to be used for both single-shot and multiple-shot color operation. The invention includes a digital camera half of the light-sensing elements of which--the "majority pixels"--are sensitive to a first primary color and the other half of which--the "minority pixels"--are divided about equally between those sensitive to a second primary color and those sensitive to a third primary color. Further, these light-sensitive elements are arranged so that by a simple lateral shift of the array, typically by the width of a single pixel, every one of the majority pixels will be moved into a position previously held by one of the minority pixels. When used in conjunction with known pixel-interpolation methods this camera produces single-shot digital images equal or better in color quality to any existing single-shot digital camera. Shooting a scene twice, with the array shifted as indicated above between the two shots, and using known interpolation techniques to determine all three primary colors at each pixel location, a final photograph essentially as good as any provided by traditional three-shot digital photography can be achieved. For cameras having the requisite array of photosensitive elements, but not incorporating a mechanism for moving the array separately from the rest of the camera, the present invention can be practiced by rotating the described camera about an axis lying in the principal plane of and passing through the principal point of the camera's lens.

Multiresolution channel normalization for ASR in reverberant environments.

Abstract: To overcome the problems related with the long impulse responses produced by reverberation, we use a long time window (high frequency resolution) analysis during the channel normalization steps of the feature extraction process in automatic speech recognition (ASR). After nor-malization, a trade between frequency and time resolution is used to increase the rate at which the time information is sampled (short-time domain), yielding an appropriate domain to derive ASR features. Experiments on data with reverberation times of about 0:5 s show that the new technique achieves signiicant performance improvement of a speech recognizer under reverberation, with only some performance degradation on clean speech.

Multispectral image restoration with multisensors

Abstract: A procedure is advanced to restore a single color image, which has been degraded by a linear shift-invariant blur in the presence of additive stationary noise. Four sensors are needed, followed by the application of the RGB-to-YIQ transformation. Subsequently, one three-dimensional (3D) Wiener filter on a sequence of two luminance component images and two two-dimensional (2D) Wiener filters on each of the two chrominance component images are needed. For the procedure to be successful, the imposition of a strongly coprime condition on the wavenumber response of two distinct sensor blur functions is necessary. The resulting well-conditioned problem is shown to provide improved restoration over the decorrelated component and the independent channel restoration methods, each of which uses one sensor for each of the three primary color components.

Color machine vision system for process control in the ceramics industry

Abstract: This paper is focused on the design of a machine vision system to solve a problem found in the manufacturing process of high quality polished porcelain tiles. This consists of sorting the tiles according to the criteria 'same appearance to the human eye' or in other words, by color and visual texture. In 1994 this problem was tackled and led to a prototype which became fully operational at production scale in a manufacturing plant, named Porcelanatto, S.A. The system has evolved and has been adapted to meet the particular needs of this manufacturing company. Among the main issues that have been improved, it is worth pointing out: (1) improvement to discern subtle variations in color or texture, which are the main features of the visual appearance; (2) inspection time reduction, as a result of algorithm optimization and the increasing computing power. Thus, 100 percent of the production can be inspected, reaching a maximum of 120 tiles/sec.; (3) adaptation to the different types and models of tiles manufactured. The tiles vary not only in their visible patterns but also in dimensions, formats, thickness and allowances. In this sense, one major problem has been reaching an optimal compromise: The system must be sensitive enough to discern subtle variations in color, but at the same time insensitive thickness variations in the tiles. The following parts have been used to build the system: RGB color line scan camera, 12 bits per channel, PCI frame grabber, PC, fiber optic based illumination and the algorithm which will be explained in section 4.

System and method for image processing

Abstract: The invention relates to a system and a procedure for image processing. The system comprises a data communication network (1) which serves as a channel for the transmission of the image being processed, digitised in an electronic form of representation, and an image processing device (2; 2a, 2b, 2c), which is connected to the data communication network (1) and which processes the image to enhance its visual quality to print the image to different formats. According to the invention, the image processing system comprises a classifying device (3), which automatically classifies the image, and a correcting device (4), which automatically corrects the image.

Image pickup system with separable/attachable image pickup device and display device

Abstract: An image pickup system comprising an image pickup device including an image pickup element for pickup the image of an object and outputting image data, a compression encoding circuit for effecting compression encoding of the image data, a wireless transmission circuit for modulating the compression encoded image data and transmitting the data to a wireless transmission channel, and a first connector adapted to be electrically and mechanically connected, in detachable manner, to a display device for displaying the image picked-up by the image pickup element and to transmit the image data from the image pickup element; and a display device including a wireless reception circuit for receiving the transmitted image data from the wireless transmission channel and demodulating the image data, an expansion circuit for expanding the demodulated image data to obtain first image data, a second connector adapted to be electrically and mechanically connected, in a detachable manner, to the first connector and to receive second image data from the image pickup device, a signal processing circuit for selectively receiving the first or second image data and processing the received image data to output an image signal of a predetermined format, and a monitor for displaying the image signal of the predetermined format.

Photographic system using chroma-key processing

Abstract: PROBLEM TO BE SOLVED: To generate a still picture with excellent quality from an output of a digital still camera by processing a 1st output signal with a 2nd output signal recorded in advance and extracting an object detected to generate a corrected image signal. SOLUTION: A chrominance value and a luminance value being major parts of a camera output signal are obtained in a step 36. Each picture element of the chrominance signal and the luminance signal is compared in a stage 37 between an object image signal from the camera and a reference signal stored via a key color calibration channel stored in a reference image memory. An output from a picture element that denotes a smaller difference from a selected threshold level is recorded in advance and the picture element is replaced with a picture element corresponding to a selected background image in a step 39. Then a chromakey, a detailed signal and a peripheral processing signal are combined in a step 35 and a corrected image having an object appearing in front of a background image selected and recorded in advance is printed out. COPYRIGHT: (C)1998,JPO

High definition television progressive scan broadcast camera

Abstract: A camera is described which is capable of meeting the United States standards for high definition television (HDTV) The camera produces a display of 1280 pixels by 720 pixels at a rate of 60 frames per second In the preferred embodiment, there is provided, as an image sensor, a frame transfer three phase buried channel CCD capable of shifting the charge from an imaging region to a storage region within a brief blanking period provided by a shuttered lens The image sensor has an arrangement of spaced electrodes which are electrically connected to shunts in the image sensor to transport charge, but are also arranged in the imaging region such that the geometry of the electrodes within each of the plurality of pixels is similar and thereby reduce the resistance present during shifting the charge from the imaging region to the storage region The image sensor further minimizes the effect of dark current from the storage section on a reproduced image, and provides for amplification of the image prior to the introduction of substantial noise Additional embodiments are described wherein: i) an anti-reflective coating minimizes distortion of the reproduced image without contamination of the camera; ii) the camera is capable of reproducing images at a variable frame rate; and, iii) the image sensor is capable of operating either in a progressive-scan mode or an interlace-scan mode

Method of adaptive and combined thresholding for daytime aerocosmic remote detection of hot targets on the earth surface

Abstract: A method of thresholding for remote detection of hot targets on earth surface based on radiometric data of spaceborne or airborne imaging optoelectronic sensors is carried out by firstly co-registering of simultaneously obtained multispectral data of an image scene containing expected hot targets in an ambient background. A preliminary detection of bright spots in the Mid-Infrared (MIR) channel is then performed by an adaptive thresholding in a moving window procedure for each pixel with its radiometric value compared to the radiometric mean value of all pixels located in the moving window. A combined thresholding procedure is then applied which consists of several successive processing procedures performed for each selected bright spot providing fixed and adaptive thresholding operations in the Thermal Infrared (TIR) channel in combination with a threshold operation using a ratio of the radiometric data in the MIR channel to the radiometric data in a Visible/Near Infrared (VNIR) channel.

Image compression using adjacent pixels and predetermined colors

Abstract: Compression for color values of pixels in a raster image of pixels, in which pixels are selected in a checkerboard-like pattern. Pixels selected by the checkerboard are not compressed at all, whereas pixels not selected by the checkerboard are compressed by using the color of the closest one of adjacent selected pixels and of a few predetermined colors.

A multi-user real-time virtual reality system and method

Abstract: A high resolution real-time multi-user augmented reality system 10 broadcasts a wide FOV video signal 22 from a plurality of image sources 12 over a distribution channel 24 to a plurality of users 25 that independently select and view different portions 42 of the video signal such that the angular resolution of the displayed video signal is constant over the range of possible viewing orientations This is accomplished by assuming that each user's position is fixed at the center 58 of a virtual sphere 54, the image sources' positions are known relative to the center of the virtual sphere, and that the users are looking at a portion of the inner surface of the sphere As a result, the flat" images generated by the image sources and the flat" images viewed by the users can be efficiently mapped onto the virtual sphere and represented as index pairs (d,n) Thus, each user extracts those pixels on the virtual sphere corresponding to the user's current FOV 46 and remaps them to a flat display 40 The video signals can be augmented with synthetic point-of-interest data such as visual overlays 26 or audio messages 28 that are registered to the video

Turbo-codes used for compressed image transmission over frequency selective fading channel

Abstract: The turbo-code is a newly developed channel coding technique with amazing error correcting capability. Turbo-codes are applied to JPEG compressed images in a wireless environment. The wireless channel is modeled as a frequency selective fading channel with a two-ray profile. Different combinations of source and channel code rates are simulated for image transmission. In addition, unequal error protection for the header syntax of JPEG compressed images is considered. It is found that turbo-codes combined with unequal error protection give excellent performance for compressed image transmission, even at a high delay spread. The optimum joint source/channel coding schemes are given at different delay spreads. The image qualities are compared both subjectively and objectively.

A CCD/CMOS image sensor array with integrated A/D conversion

Abstract: A CCD/CMOS digital camera with integrated drivers is reported. The chip uses a 32/spl times/24 pixels CCD Interline-Transfer image sensor with 32 CCD/CMOS single-slope analog-to-digital converters. This highly scalable architecture is suitable for implementing high resolution modular image sensors for digital vision applications. Correlated Double Sampling technique could be integrated on each readout channel to suppress kTC and fixed-pattern noise.

Channel navigation system and method

Abstract: PROBLEM TO BE SOLVED: To visualize a program video image and to conduct navigation easily understood by the user by using a 3-dimension CG texture mapping for the navigation of a multi-channel broadcast. SOLUTION: A navigation tuner controller 18 controls a tuner 3 and gives a video signal of a searched channel sequentially to an image processing section 12 one after another A moving video image of each channel is subjected to texture mapping in a texture memory 13, subjected to image processing as if to turn over pages of a book in a computer graphic section 17, combined with EPG data and the result is displayed on a half screen of a display device. When an object video image is found out, a book mark is added as an image to correspond to the channel and finally the channel of the object is selected. COPYRIGHT: (C)1999,JPO

Adaptive color halftoning for minimum perceived error using the blue noise mask

Abstract: Color halftoning using a conventional screen requires careful selection of screen angles to avoid Moire patterns. An obvious advantage of halftoning using a blue noise mask (BNM) is that there are no conventional screen angle or Moire patterns produced. However, a simple strategy of employing the same BNM on all color planes is unacceptable in case where a small registration error can cause objectionable color shifts. In a previous paper by Yao and Parker, strategies were presented for shifting or inverting the BNM as well as using mutually exclusive BNMs for different color planes. In this paper, the above schemes will be studied in CIE-LAB color space in terms of root mean square error and variance for luminance channel and chrominance channel respectively. We will demonstrate that the dot-on-dot scheme results in minimum chrominance error, but maximum luminance error and the 4-mask scheme results in minimum luminance error but maximum chrominance error, while the shift scheme falls in between. Based on this study, we proposed a new adaptive color halftoning algorithm that takes colorimetric color reproduction into account by applying 2-mutually exclusive BNMs on two different color planes and applying an adaptive scheme on other planes to reduce color error. We will show that by having one adaptive color channel, we obtain increased flexibility to manipulate the output so as to reduce colorimetric error while permitting customization to specific printing hardware.

Video server, control method therefor and storage medium

Abstract: PROBLEM TO BE SOLVED: To supply video data of size different from each client SOLUTION: A channel management means 108 manages it that to which channel a connected client belongs, an image size for each channel and a coding system An image capture means 102 receives a video signal from an image input means 101 such as a camera sequentially as digital video data, and an image magnification means 103 generates an image of a plurality of sizes Then an image compression means 104 compresses image data of each size obtained through magnification and a delivery means 105 delivers the compressed image to each client of each channel COPYRIGHT: (C)1999,JPO