Showing papers on "Channel (digital image) published in 1993"

Tree-structured nonlinear filter and wavelet transform for microcalcification segmentation in mammography

Abstract: The development of an extensive array of algorithms for both image enhancement and feature extraction for microcalcification cluster detection is reported. Specific emphasis is placed on image detail preservation and automatic or operator independent methods to enhance the sensitivity and specificity of detection and that should allow standardization of breast screening procedures. Image enhancement methods include both novel tree structured non-linear filters with fixed parameters and adaptive order statistic filters designed to further improve detail preservation. Novel feature extraction methods developed include both two channel tree structured wavelet transform and three channel quadrature mirror filter banks with multiresolution decomposition and reconstruction specifically tailored to extract MCC's. These methods were evaluated using fifteen representative digitized mammograms where similar sensitivity (true positive (TP) detection rate 100%) and specificity (0.1 - 0.2 average false positive (FP) MCC's/image) was observed but with varying degrees of detail preservation important for characterization of MCC's. The image enhancement step proved to be very critical to minimize image noise and associated FP detection rates for MCC's or individual microcalcifications.

Pipelined image processing system for a single application environment

Abstract: A control system for pipelined image processing emulates a multi-tasking environment using a single tasking application. A number of predefined image processing tasks are provided in a library. When a host application needs a processed image from an image source, the host application creates a pipeline of initialized instantiations of one or more of the tasks from the library. When the host application invokes the pipeline, the first data request for the heater of the image travels upstream in a first channel. The processed image header is returned down the first channel. Then a data request for scanlines of image data is sent upstream in a second data channel. The data request ripples upstreamwardly to the upstream-most instantiation of one of the tasks from the task library. The upstream-most instantiation of a task obtains a scan line from an image data source and returns it downstreamwardly to the host application in the second channel. Each instantiation of a task from the task library further operates on the image data. Once all of the scanlines have been processed, the memory allocations and data structures created during initialization are released to free up that memory.

Apparatus and method for stabilizing a picture of an image system

Abstract: Disclosed is an apparatus for and method of stabilizing a picture in an image system during the changing of a broadcast channel. Since channel altering causes noise in synchronization, and an unstable picture when performing automatic frequency tuning (AFT) and automatic gain control (AGC), an image signal of the previous channel is stored in an image memory before being changed, and output onto the screen using a switch controlled by a microcomputer during the unstable period for AFT and AGC, instead of the image signal of the altered channel. The image signal of the altered channel is output after the output of an automatic controlled is stabilized.

Recovery of block-coded images from channel errors

Abstract: A method to recover good-quality images from severe transmission errors in a block coding environment is proposed In block-coded images, channel errors usually result in annoying blocky noise The proposed scheme tries to remove or conceal this blockiness through error detection and block replacement The single bit-error dominance in binary transmission and high pixel correlation of common images are utilized Specifically, assuming that the boundaries of image blocks in the received bit stream are detectable, all the bit patterns at unit Hamming distance from the received one are first decoded into candidate image blocks Then, the candidate image block with minimum gray-level transition across the block boundaries is selected for final recovery This method works not only on fixed-length binary codes but also on variable-length binary codes as long as block boundaries are known to the receiver The comparative performance and possible improvements of the scheme are studied >

Method for generating three-dimensional spatial images

Abstract: A method for generating a three-dimensional spatial image that has a greatly improved three-dimensional (3-D) effect. The method utilizes a series of two dimensional stereoscopic image pairs which have been composed by different scenes photographed on different bases or computer generated using a single channel or multi-channel optical image projector, beam splitter, camera, and a retro-reflective screen.

Image pickup device

Abstract: PURPOSE:To enable an efficient color separating processing without using a trimming filter in an image pickup device for picking up an image by each different image pickup means at every color component through a color separating means. CONSTITUTION:In the image pickup device provided with an optical member 2 for color-separating light from which an image is to be picked up in plural directions and outputting color-separated components and plural image pickup means 3R, 3G, 3B for converting the color-separated light components through the means 2 into image pickup signals corresponding to respectively different color components, a value obtained by multiplying the image pickup signal of another channel by a prescribed coefficient is subtracted from the image pickup signal of a certain channel which is outputted from one of the means 3R, 3G, 3B to remove the residual of the color component of another channel which is included in the image pickup signal of each channel concerned.

Automatic generation of custom document image decoders

Abstract: A framework for document image recognition, called document image decoding (DID), that supports the automatic generation of custom document recognition systems from user-specified document models is discussed. A document recognition problem is viewed as consisting of a message source, an imager, a noisy channel, and an image decoder (recognizer). The inputs to a decoder generator are explicit models for the message source, imager and channel; the output is a specialized program that decodes an image in terms of these models. The models used in DID are based on a stochastic attribute grammar model of document production. Use of an automatically generated decoder to analyze telephone yellow pages is described. >

Document image decoding using Markov source models

Abstract: The authors describe a communication theory approach to document image reconstruction, patterned after the use of hidden Markov models in speech recognition. A document recognition problem is viewed as consisting of three elements-an image generator, a noisy channel, and an image decoder. A document image generator is a Markov source which combines a message source with an imager. The message source produces a string of symbols which contains the information to be transmitted. The imager is modeled as a finite-state transducer, which converts the message into an ideal bitmap. The channel transforms the ideal image into a noisy observed image. The decoder estimates the message from the observed image by finding the a posteriori most probable path through the combined source and channel models using a Viterbi-like algorithm. Application of the proposed method to decoding telephone yellow pages is described. >

A 1/2-in 380 k-pixel progressive scan CCD image sensor

Abstract: A progressive-scan interline-transfer CCD (charge coupled device) image sensor (PS-CCD) that can read out vertical signal packets without mixing is presented. It can solve ill-matched resolutions. This 380-k-pixel PS-CCD provides a vertical resolution of 480 TV lines. The schematic of this device is shown. The image area is 6.45 (H) mm*4.84 (V) mm. The number of pixels without optical blacks is 768 (H) *494 (V), and the size is 8.4 (H) mu m*9.8 (V) mu m. These specifications are suitable for 1/2-in lens format. To realize a PS-CCD, three techniques are used: three-phase three-level electrode vertical CCD, dual horizontal CCD with a compound channel, and dual-channel output. The characteristics of the image sensor are shown. 146-mV/1* sensitivity is obtained from one pixel for light with a color temperature of 3200 K and a saturation voltage of 600 mV. Smear is reduced to -86 dB. Horizontal resolution is 570 TV lines. >

Synchronized zoom electronic camera system

Abstract: The present invention is directed to a multiple camera system which captures a photo image on film and captures and stores an electronic image on a magnetic recording media. The system has two operating states. In the "compose" or "view" state the electronic image channel is operated at a first gain setting, color temperature and F-stop to provide a real time moving image on a monitor. In the capture state the electronic gain, color temperature, and F-stop of the electronic camera are altered to collect or capture an electronic image during strobe illumination. The system utilizes a pair of dedicated zoom lenses, which are mechanically corrected for parallax error and the focal length of the two lenses are matched and linked together so that their focal lengths may be altered simultaneously by the operator.

Two-channel optical inspection system for pipelines and ducts - has spectral filters rotating with camera head about axis of pipe and stationary matrix image sensor

Abstract: The rotary portion (14) of the video camera head carries colour filters (1, 2) sepg. a blue optical channel (3) from a red channel (4). The two-channel signal from a co-rotating beam splitter (5) is focused (8) on a CCD colour matrix (7) wired to a signal processor (9), frame grabber (12) and video recorder or optical disc (13). Two monochrome images of the pipe wall are reproduced on monitors (10, 11). In an alternative embodiment a near infrared and a visible channel are distinguished by edge filters. USE/ADVANTAGE - Esp. in waste water drainage systems, continuous view of entire internal surface is obtainable without foreshortening and with secure control of carriage.

Transmission of wavelet transform coded TV images on a noisy channel

Abstract: A compression algorithm for the bit rate reduction of digital TV images using the wavelet transform is described. The TV images are decomposed by the wavelet transform into a lower-resolution signal and high-frequency subbands. Some issues related to the transmission of the compressed TV images on a noisy channel are also analyzed. Channel noise can determine synchronization loss if variable-length codes are employed and, hence, a distortion in the reconstructed images. A technique to recover the synchronization losses is presented. The effects of different channel coding techniques on the reconstructed image quality are also investigated. Computer simulations have been used to characterize the performance of the proposed technique. >

Novel digital unsharp masking algorithm for color images

Abstract: A Digital Unsharp Masking algorithm is proposed for enhancing color image in color reproduction systems. The proposed Digital Unsharp Masking filter uses variable enhancement gain to adapt to edge and tone features of the image. By including edge and white/black color detection mechanisms, the new Digital Unsharp Masking algorithm is able to perform detail enhancement without increasing graininess. The tone detection enables the proposed Digital Unsharp Masking to control the sharpness of different tone regions, i.e., highlight, midtone, and shadow, in the scanned image separately. A luminance channel is used as an unsharp channel in the algorithm. The color shift problem faced by existing digital unsharp masking algorithm is eliminated.

Color solid image pickup device

Abstract: PURPOSE:To allow this color solid image pickup device to correspond to both of out-of-green type and full channel compensating type outline compensating circuits without changing the fixed positions of solid image pickup elements fixed on a prism. CONSTITUTION:An aborting period corresponding to one horizontal scanning period (1H) can be properly set up in vertical charge transfer within the vertical blanking period of the solid image pickup element 4 corresponding to green light by means of a driving circuit 6 for plural solid image pickup elements 3 to 5 and a switch 21. Thereby the out-of-green type outline compensating circuit to be built in a camera head is selected for simple application to be used only by the camera head or the full channel compensating type digital outline compensating circuit built in a camera control unit or the like can be selected for orthodox application requiring high picture quality.

Automatic x-ray exposure controller

Abstract: PURPOSE:To easily confirm a natural illumination part and to improve operability. CONSTITUTION:At the automatic X-ray exposure controller equipped with a natural illumination part 8 to convert the optical images of an image intensifier 4 to electric signals and an exposure detection circuit 9 to calculate an average value by detecting the output of an arbitrary channel 8n due to the output or manual selection of the channel 8n with proper exposure depending on automatic selection, a display part is provided to display a character or a symbol showing the part of the detected channel 8n, superimpose control circuit 13 is provided to display this character or symbol, and superimpose circuit 14 is provided. Therefore, in the case of automatic selection, it can be confirmed whether the channel 8n is correctly selected or not and in the case of manual selection, it can speedily be confirmed which channel 8n is used for displaying images.

The electronic video operative laparoscope

Abstract: A new 14-mm electronic video operative laparoscope accommodates a 5-mm operative channel. The video image sensor is located at the distal end of the laparoscope. The image quality is far superior to that of the standard video camera systems that attach to rigid endoscopes. Additional advantages are improved maneuverability, elimination of focusing, superior illumination system, and the capability to interchange with conventional video equipment. This instrument marks the next generation of laparoscopes.

Printer output controller

Abstract: PURPOSE: To improve the flexibility in the case of copying an image by dividing image data used to display an image on a printer or the like into signals in a synthesis enable way and finally synthesizing the signals. CONSTITUTION: A data stream being image data including color information and transferred to a printer is combined in a combiner 36 by using data that is obtained from data of each type recovered in a sub channel 16, a mask channel 30, a constant color channel 44 and command channels 60, 62 by an instruction of a fetcher 40 from a system bus 10 and the combined data stream is outputted.

Method and apparatus for transmitting encoded blocks of video signals at different channel rates

Abstract: Encoded blocks of video information are selected for transmission at a plurality of channel rates based on the corresponding location of the portions of the video image represented by the encoded blocks. Each encoded block is designated an image type which determines its transmitted channel rate. The image types are associated with spatial positions of a video image such that encoded blocks within a first area of the video image are designated a first image type and encoded blocks within a second area of the image are designated a second image type. In general, data blocks representing the central portion of the video image are transmitted at a channel rate having less susceptibility to noise or other degradation, thereby ensuring that such portion can be received in fringe areas.

Single filters for combined image geometric manipulation and enhancement

Abstract: This paper presents algorithms for simultaneous image geometric manipulation and enhancement. Single filters are developed for combined image translation, resizing, rotation, and enhancement of both single channel and multichannel/color images. Single filters have advantages for real time implementation and for minimizing artifacts produced by the sequential operations on the images. A filter structure is proposed for image sharpening, softening, blurring, and edge emphasis filtering. With the appropriate choice of the parameters, it is shown that the proposed structure can implement unsharp masking, local statistical filtering, and edge emphasis filtering. Image translation, resizing, and rotation geometric operations are combined with the structure in developing single filters. Closed form expressions are developed for real time implementation of the filters through lookup tables with different types of interpolations and for both linear and nonlinear enhancement kernels. A multichannel generalization of the algorithm is presented for simultaneous color image geometric manipulation and enhancement. Schemes are proposed for adapting the degree of enhancement based on local image information. The algorithm is applied for a number of electronic imaging applications and the evaluation results are presented.

Video ghost cancellation

Abstract: Ghosts accompanying a composite video signal are suppressed using one filter to suppress macroghosts and another filter to suppress microghosts, the filtering parameters of each of these filters being adjustable in response to digital programming signals generated by a computer. Computational methods are described, each of which includes data acquisition and channel characterization steps followed by a decision step comparing the most recent set of channel characterization results with the next most recent set to determine whether stable ghosting conditions obtain. The data acquisition and channel characterization steps are looped back through until stable ghosting conditions obtain, so the subsequent calculations of the filtering parameters for the filter used for suppressing macroghosts are accurately performed. Where the filter to suppress macroghosts comprises IIR and FIR sections for suppressing post-ghosts and preghosts, respectively, these calculations are carried out to a great extent on a separable basis, simplifying the calculations appreciably. Then, each of these methods performs a step of calculating the filtering parameters for the FIR filter used for suppressing microghosts. This step is followed by further data acquisition and channel characterization steps, followed by a decision step comparing the most recent set of further channel characterization results with the next most recent set of further channel characterization results to determine whether they are substantially the same. If the sets of further channel characterization results are substantially the same, either method loops back to the further data acquisition step; if the sets differ appreciably, either method resets the adjustable filtering parameters for the filters to initial values and the method restarts automatically.

CMOS digital retina chip with multi-bit neurons for image coding

Abstract: The authors describe a CMOS digital retina chip with neurons having multi-bit output for image coding from analog to digital formats. The neuron having a 1-bit output model can easily be implemented by the use of CMOS inverters. It has individual digital inputs, a common quantized output and a comparator. The weight vector is given as a fixed numerical value by a channel conductance for pull-up PMOS and pull-down NMOS transistors, respectively. The delayed binary outputs of neurons in the neighborhood are directly connected to the digital inputs. The next state of the network is computed from the current state at some neurons in any time interval. To reduce the error between the input analog gray image and the output digital image, a two-bit image coding method is proposed. >

Sensor-detecting and compensating system and method of image restoration and trouble

Abstract: PURPOSE: To detect a faulty sensor by enhancing a local contrast of an image of a video display device. CONSTITUTION: A plurality of input signals, including desired image data for a video display device are A/D-converted by an A/D converter 3, stored in a memory 4, interpolated as required, and the result is outputted (6), and an average value is calculated with respect to each channel by an accumulator 7. A microprocessor 8 is used for calculation to eliminate outputs lower than the average value as error values based on the average, a correction amount is calculated to make the average equal for each channel, and the amount is stored in a memory 9. Then as required, in order to obtain a desired resulting signal, the input signal and a reproduced signal are summed by an adder 10 for producing an output signal.

Review of video compression which depends on visual perception limits

Abstract: Video compression is achieved by leaving out unnecessary information in an image. This is done by leaving out information that can be predicted (entropy encoding) or by leaving out information the visual system cannot use. Entropy encoding procedure on exact replica of the original image until the image unpredictability exceeds the channel capacity--at which point it fails. Entropy encoding has been discussed widely in the literature. Encoding based on the limits in perception produces an image in which there are measurable differences between the original and reconstructed image. However, these differences are kept below the thresholds of perception. A wealth of information exists in the vision research community on perception thresholds for various visual stimuli. This paper will review these perception limits and show how they have been used or may be used in visually lossless compression.© (1993) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Twin-Channel (P and N) CCD Image Sensor with Cross Anti-Blooming

Abstract: A new class of Frame-Transfer CCD image sensors is presented which uses both electrons and holes as information carriers and has a novel cross anti-blooming structure for overexposure protection. The device consists of alternate columns of p-and n-channel CCD's shown in Fig. 1 which forms two separately operating p-and n-type imagers. This concept uses the n channel as a channel isolator for the p-channel and vice versa, and has these advantages: (1) The complete area of the image section is active because no light-insensitive channel-stop area is required; (2) Both photon generated carriers ? electrons and holes ? can be stored and transported, thus doubling the useful information; (3) In a typical four-phase clocking system as shown in Fig. 1, the electron pixels and the hole pixels are separated by half a pixel pitch in both the vertical and horizontal directions, thereby improving the pixel-packing density, aliasing, and Moire suppression; (4) The pattern also forms a line-qujincunx sampling grid, which offers many advantages for signal processing, especially when the p- and n-output signals are simultaneously available; (5) This pixel configuration is also ideally suited for realizing a progressive-scan imager.

Multichannel restoration of single channel images us in g a wavelet d eco m p 0 sit ion

Abstract: In this paper, multichannel linear filt.ering is applied to the restoration of single channel images t.hrough the use of a wavelet decomposition. A new matrix structure for the separable 3-D wavelet transform is present.ed which allows the transformation of block circulant operat,ors, found in 2-D linear filtering problems, into semi- block circulant operators, which are defined here. These operators are easily treated as block diagonal matrices in the wavelet-frequency domain. An adaptive Wiener filter is implemented in t,his domain, which utilizes the cross correlat,ions between subbands in the decomposition to subst antially improve the restoration of noisy-blurred images over that found with single channel filtering. This improvement is especially evident when the power spectrum of the original image is available.

Document image decoding using Markov source models

Abstract: This paper describes a communication theory approach to document image recognition, patterned after the use of hidden Markov models in speech recognition. In general, a document recognition problem is viewed as consisting of three elements -- an image generator, a noisy channel, and an image decoder. A document image generator is a Markov source (stochastic finite-state automation) which combines a message source with an imager. The message source produces a string of symbols, or text, which contains the information to be transmitted. The imager is modeled as a finite-state transducer which converts the one-dimensional message string into an ideal two-dimensional bitmap. The channel transforms the ideal image into a noisy observed image. The decoder estimates the message, given the observed image, by finding the a posteriori most probable path through the combined source and channel models using a Viterbi-like dynamic programming algorithm. The proposed approach has been applied to the problem of decoding scanned telephone yellow pages to extract names and numbers from the listings. A finite-state model for yellow page columns was constructed and used to decode a database of scanned column images containing about 1100 individual listings. Overall, 99.5% of the listings were correctly recognized, with character classification rates of 98% and 99.6%, respectively, for the names and numbers.

Rotation invariant color pattern recognition using a circular harmonic minimum average correlation energy filter

Abstract: A minimum average correlation energy (MACE) filter is applied to rotation invariant color pattern recognition. We present a method for calculating the circular harmonic component MACE filter for an arbitrary order. This filter has the advantage of being useful for several color channels simultaneously, avoiding the preparation of several filters, one for each channel. The correlations obtained for every different channel are combined by arithmetic operations, producing only one output plane. Both, computer simulations and optical experiments are presented proving the discrimination abilities for this implementation.

Banding reduction via color channel interlacing

Abstract: A process for altering the phase of banding artifacts of a printing device deals with the separation of low frequency luminance modulation into higher frequency colored modulation. The individual writing element that is used to print each line of an image is changed between the color channels. In the process, each channel is printed so that original image data are registered. Lower frequency neutral bands are then converted to higher frequency colored bands to reduce visibility of the artifacts.

Apparatus for reproducing high definition color video signal.

Abstract: Disclosed is a reproducing apparatus which plays a recording medium on which a color video signal is recorded as three channel signals acquired by expanding time axes of one luminance signal and two color difference signals representing the color video signal and combining the expanded luminance signal and the expanded color difference signals in a predetermined format while subjecting the color difference signals to a line-sequential process, and which can clear disturbance on a reproduced image in a short period of time when the mode changes to a normal playback mode from a special playback mode. After the reproduced channel signal is written in a memory, write and read timings at the reading time are monitored while performing reverse conversion to the signal conversion done at the time of producing the channel signal, thereby keeping the phase difference between write and read timing signals constant.