112 results about "Distortion function" patented technology

Distortion modeling produces distortion models for use by a distortion synthesizer to synthesize the harmonic distortion effects of audio distortion devices. A sinusoidal waveform is distorted by an audio distortion device and analyzed using a Fourier transform to produce a distortion model comprising harmonic amplitude and phase parameters. A phase correction process compensates for phase shifts induced by the audio distortion device. The distortion synthesizer uses a distortion function that distorts a digital audio signal according to the distortion model. The distortion model can be modified to alter the distortion effect and can be stored in a data-storage device for later retrieval. A frequency bandsplitter and signal mixer allow the distortion effect to be applied only to the low frequency content of the digital audio signal, thus providing spectral headroom to suppress the production of aliasing noise. Aliasing-noise suppression is provided for a full-bandwidth signal by up-converting the sampling rate of the signal before applying the distortion function and down-converting the sampling rate afterwards. A process is provided to remove the direct-current component that may be induced into the signal by the distortion function.

An amplifier with adjustable (pre)distortion, a predistortion adjustment circuit, systems and networks including such amplifiers and circuits, and methods for adjusting (pre)distortion in an analog amplifier. The amplifier architecture generally includes (a) a predistortion circuit configured to (i) select a value for a predistortion function from a plurality of different predistortion values, and (ii) apply the selected predistortion value to an input signal to generate a predistorted input signal; (b) an amplifier configured to amplify the predistorted input signal and provide an output signal therefrom; and (c) an adjustment circuit configured to adjust selection of the predistortion function value in response to a predetermined parameter value of the amplifier. By adjusting the predistortion function, the amplifier provides an output signal in a linear power range over a range of amplifier parameter values and avoids overcompensation that can occur when the predistortion signal is not adjustable. Furthermore, the adjustments are made in response to changes in amplifier input and / or control parameters, enabling the amplifier to stay in the linear range, rather than respond to changes that first cause the amplifier to fall out of linearity. The systems generally include the architecture, circuit or an integrated circuit that embodies one or more of the inventive concepts disclosed herein. The methods generally include the steps of (1) predistorting an input signal in accordance with a digital predistortion function to provide a predistorted signal, (2) adjusting the digital predistortion function in response to a predetermined parameter value of an amplifier, and (3) amplifying the predistorted signal with the amplifier to produce the amplified signal.

There is disclosed a system and method for video coding, and more particularly to video coding that uses structural similarity (SSIM) based rate-distortion optimization methods to improve the perceptual quality of decoded video without increasing data rate, or to reduce the data rate of compressed video stream without sacrificing perceived quality of the decoded video. In an embodiment, the video coding system and method may be a SSIM-based rate-distortion optimization approach that involves minimizing a joint cost function defined as the sum of a data rate term and a distortion functions. The distortion function may be defined to be monotonically increasing with the decrease of SSIM and a Lagrange parameter may be utilized to control the trade-off between rate and distortion. The optimal Lagrange parameter may be found by utilizing the ratio between a reduced-reference SSIM model with respect to quantization step, and a data rate model with respect to quantization step. In an embodiment, a group-of-picture (GOP) level quantization parameter (QP) adjustment method may be used in multi-pass encoding to reduce the bit-rate while keeping similar perceptual video quality. In another embodiment, a frame level QP adjustment method may be used in single-pass encoding to achieve constant SSIM quality. In accordance with an embodiment, the present invention may be implemented entirely at the encoder side and may or may not require any change at the decoder, and may be made compatible with existing video coding standards.

A method for displaying a region of interest within visual information on a display screen of a computer, the region of interest including a focal region and a base region. The method includes the steps of: providing means for selecting at least one parameter for transforming at least one of the region of interest, the focal region, and the base region; selecting the parameter using the means for selecting; transforming the visual information in accordance with a predetermined distortion function and the parameter to produce transformed visual information; and, displaying the transformed visual information on the display screen.

There is disclosed a method of controlling an envelope tracking amplification stage comprising an envelope modulated power supply, the method comprising: determining a shaping function to be applied to an envelope signal for controlling the envelope modulated power supply in dependence on a system linearity objective in a region of operation of the amplifier in which the output power of the amplifier is dependent upon the supply voltage; and determining a pre-distortion function to be applied to an input signal to be amplified in dependence on a further linearity objective of the system, in a region of operation of the amplifier in which the output of the amplifier is dependent upon the input power to the amplifier.

A method for generating a presentation of a region-of-interest in an information representation including the steps of: selecting a viewpoint for the region-of-interest; creating a lens surface for the region-of-interest; the lens surface having a focal region and a shoulder region surrounding the focal region; creating a transformed presentation by: determining boundaries in the representation for the focal region and the shoulder region; determining boundaries on the lens surface corresponding to the boundaries in the representation by applying a distortion function defining the lens surface to the boundaries in the representation; perspectively projecting the boundaries on the lens surface onto a plane spaced from the viewpoint; and, copying information in the representation lying within the boundaries in the representation onto the focal region and the shoulder region of the lens surface using respective focal region and shoulder region stretch bit-block transfer operations; and, displaying the transformed presentation on a display screen to generate the presentation of the region-of-interest.

A method for generating a presentation of region-of-interest in an information representation including the steps of: selecting a viewpoint for the region-of-interest; selecting a location for the region-of-interest; creating a lens surface having a predetermined location for the region-of-interest; creating a transformed presentation by: determining a mapping for pixel coordinates from the representation to the lens surface by applying a distortion function defining said lens surface to said pixel coordinates; calculating a vector from the predetermined location to the location; and, copying pixel information from the representation to the lens surface according to the mapping as displaced by the vector; and, displaying the transformed presentation on a display screen to generate the presentation of the region-of-interest.

Aspects of a method and system for estimating and compensating for non-linear distortion in a transmitter using data signal feedback are presented. Aspects of the system may include a method and system by which predistortion values, for compensating for non-linear distortion, may be computed based on feedback signals generated in response to wideband input signals. The wideband input signals may comprise a plurality of frequency components and / or signal amplitudes. The predistortion values may be computed by time-synchronizing a wideband input signal generated at a given time instant, and the feedback signal generated at a subsequent time instant in response. A predistortion function may be computed by computing predistortion values for a plurality of signal amplitude values and / or IC operating temperatures. The computed values may be stored in a lookup table and retrieved to predistort subsequent wideband input signals based on the amplitude of the signals and / or the IC operating temperature.

Described is a technique for viewing a document page on a small display such as a mobile phone or PDA. The page can come from a scanned document (bitmap image) or an electronic document (text and graphics data plus metadata). The page with text and graphics is segmented into regions. For each region, a scale-distortion function is constructed based on image analysis. During interactive viewing of the document, as the user navigates by moving the viewport around the page, the zoom factor will be automatically adjusted by optimizing the scale-distortion functions of the regions in the viewport.

A system and methodology for concealing an error in a video signal is provided. In accordance with one aspect of the present invention, the system and methodology employ a Spatio-Temporal Boundary Matching Algorithm, which utilizes a distortion function that takes into account both the spatial and temporal smoothness properties of a video sequence. Further, the methodology for concealing an error in a video signal comprises receiving a video signal having an erroneous frame, creating a candidate set of motion vectors, selecting a motion vector from the candidate set of motion vectors that best keeps temporal and spatial continuity through the erroneous frame, and reconstructing the erroneous frame using the selected motion vector.

Methods and systems efficiently apply known distortion, such as of a camera and lens, to source image data to produce data of an output image with the distortion. In an embodiment, an output image field is segmented into regions so that on each segment the distortion function is approximately linear, and segmentation data is stored in a quadtree. The distortion function is applied to the segmented image field to produce a segmented rendered distortion image (SRDI) and a corresponding look-up table. To distort a source image, a location in the output image field is selected, and the uniquely colored segment at the same location in the SRDI is found. The look-up table provides the local linear inverse of the distortion function, which is applied to determine from where in the source image to take image texture data for the distorted output image.

The invention discloses a method and apparatus for determining inter-frame coding modes, which compares the rate-distortion function cost of the skip mode with the presupposition current value of the first threshold. If the rate-distortion function cost of the skip mode is smaller than the current first threshold, then the skip mode is determined to be the optimal mode under the inter-frame prediction mode; otherwise, the optimal mode under the inter-frame prediction mode is determined from the other modes under the inter-frame prediction mode, the rate-distortion function cost of which is subsequently compared with the presupposition current value of the second threshold. If the rate-distortion function cost of the optimal mode under the inter prediction mode is smaller than the current second threshold, then the optimal mode is determined to be the inter-frame coding mode; otherwise, the smallest one among the optimal modes under the intra prediction mode and the optimal modes under the intra prediction mode is determined to be the inter-frame coding mode. The invention has no need of calculating the rate-distortion function cost of all the modes, thus reducing the calculation work and enhancing the coding speed.

The invention discloses a sparse depth network based polarization SAR (Synthetic Aperture Radar) image classification method. The implementation of the sparse depth network based polarization SAR image classification method comprises step 1, inputting an image; step 2, performing filtering; step 3, extracting features; step 4, constructing and training a sparse depth network; step 5, performing prediction and classification; step 6, outputting a result. Compared with the existing method, an energy function can be minimized, a distortion function can be controlled within a certain range to enable a hidden layer to be sparse, and accordingly the calculation is greatly reduced, the generalization capability is high, and the classification accuracy is high.

The invention discloses a video steganography method based on a motion vector, which comprises the following steps: the type of each frame of a video sequence is judged; if the t-th frame is the key I frame, the motion vector collection of the frame is set up to null; if the t-th frame is the predictive P frame, motion estimation is performed to the frame to obtain the motion vector collection, and preset distortion function is used for performing embedded distortion definition to the motion vector collection; after the types of all the frames of the video sequence are judged and after the embedded distortion definition is performed to the motion vectors of all the P frames, syndrome-trellis codes (STC) are used for embedding secret information by taking all the motion vectors of the video sequence as carriers so as to obtain motion vector collection subjected to modification, and then compressed coding is performed to each frame of the video sequence in sequence to obtain the coding bit stream of the video sequence. Through the method disclosed by the invention, the anti-detection performance of embedding secret information is improved, and low bit rate expansion of the coding bit steam and the reconstruction of excellent visual quality of the video are ensured.

An input signal is pre-distorted to reduce distortion resulting from subsequent signal amplification. Frequency-dependent pre-distortion is preferably implemented in combination with frequency-independent pre-distortion, where the frequency-dependent pre-distortion is generated by expanding the derivative of a product of a pre-distortion function and the input signal and then relaxing constraints on the pre-distortion function and / or on frequency-dependent filtering associated with the frequency-dependent pre-distortion. In one implementation, four different frequency-dependent pre-distortion signals are generated for the expansion using up to four different pre-distortion functions and up to four different frequency-dependent filters.

A scalable video codec includes an encoder that encodes an original moving picture; a rate control unit that allocates an optimal amount of bits for each coding unit based on a bit-rate desired by a user; a pre-decoder that receives a bit-stream and extracts a bit-stream having an appropriate amount of bits; and a decoder that decodes image sequences of the moving picture from the extracted bit-stream, so as to reconstruct the original moving picture. In particular, the present invention focuses on the operation performed in the rate control unit 340. The rate control unit operates a definition step of a bit-rate function available for use in the predecoder, a pre-summation step to thereby obtain the uniform visual quality, an approximation to determine the distortion function, and a normalization step to allow the total allocated bit-rates to be equal to a target bit-rate.

An input signal is pre-distorted to reduce distortion resulting from subsequent signal amplification. Frequency-dependent pre-distortion is preferably implemented in combination with frequency-independent pre-distortion, where the frequency-dependent pre-distortion is generated by expanding the derivative of a product of a pre-distortion function and the input signal and then relaxing constraints on the pre-distortion function and / or on frequency-dependent filtering associated with the frequency-dependent pre-distortion. In one implementation, four different frequency-dependent pre-distortion signals are generated for the expansion using up to four different pre-distortion functions and up to four different frequency-dependent filters.

The present invention relates to a digital pre-distortion power amplification device and method with a bandwidth of 100M, wherein the polynomial pre-distortion function adopted by the pre-distortion processing algorithm is jointly determined by the instantaneous input signal and the previous input signal. The present invention is a broadband digital predistortion power amplifying device that works on a 3.5GHz frequency band, has a working bandwidth greater than 100MHz, and modulates signals of OFDM signals.

A method for residual echo suppression is provided. Embodiments may include receiving an original reference signal and applying a distortion function to the original reference signal to generate a second signal. Embodiments may include generating a non-linear signal from the distortion function that does not include linear components of the original reference signal. Embodiments may also include calculating a residual echo power of a linear component and a non-linear component, wherein the linear component is based upon the original reference signal and the non-linear component is based upon the non-linear signal. Embodiments may further include applying a room model to each of the original reference signal and the non-linear signal and estimating a power associated with the original reference signal and the non-linear signal. Embodiments may include calculating a combined echo power estimate as a weighted sum of a weighted original reference signal power and a weighted non-linear signal power.

The present disclosure relates to a method for calibrating a projector. The method includes projecting a test pattern onto a scene or an object within the scene and capturing the test pattern using a camera. Once the test pattern image has been captured by the camera, the method further includes estimating by a processing element a perspective projection matrix, warping the estimated projection matrix based on a non-linear distortion function, and modifying the projector to project light based on the distortion function. The present disclosure also relates to a presentation or projection system including two types of projectors for projecting an output presentation having a second image overlaid on a first image.

A model stored in a memory accessible by a video transcoder includes a first rate-distortion function modeling a requantization of an input video. A second-rate distortion function models a resynchronization marker insertion rate for the transcoded video, and a third rate-distortion function models an intra-block insertion rate for the transcoded video.

The invention relates to a correction algorithm for the image distortion of an optical fingerprint collector. Fingerprint images acquired by a traditional optical fingerprint collector more or less have different degrees of image distortion which is non-linear and easy to influence the matching effect. The correction algorithm for the image distortion of an optical fingerprint collector, which is disclosed in the invention, finishes image correction by deducing an image distortion function through a corresponding relation between distorted images acquired on the optical collector of square grids and grid control points of square grid images. Linear and non-linear distorted fingerprint images acquired by the optical fingerprint collector are corrected by the invention so that the same fingerprint can be accurately matched under homologous and nonhomologous conditions, and fingerprint images are propelled to develop towards a standardization direction.

The invention discloses a predistortion device and a predistortion method based on a precise inverse solution memory polynomial model equation, belonging to the predistortion technology in the field of communication and aiming to solve the problem on lowered system performance due to excessively large computing error in the traditional predistortion algorithm based on polynomial model identification. The predistortion device comprises a digital predistorter (100), a power amplifier model parameter estimation module (106) and a predistortion function computing module (107). The predistortion method comprises two processes of modeling a power amplifier and computing a predistortion function. The predistortion device and the predistortion method are both inverse functions based on precise solution memory polynomial model equation, and the precise predistortion function is obtained by a way of constructing an equation of higher degree in one unknown and computing a real root of the equation. According to the predistortion device and the predistortion method, the computing error can be reduced, and the frequency spectrum growth can be effectively inhibited, so that the system performance is improved.

A method and apparatus for distortion image correction are provided. The method comprises the following steps of: determining a distortion function of an image pickup device according to an original distortion image and a calibration template image, and correcting a geometric position of the original distortion image according to the distortion function to obtain a first distortion image; converting a first distorted image from an RGB image format to a YCbCr image format, and determining brightness values and color difference values of initial pixel points on the first distorted image in the YCbCr image format; correcting the brightness value and color difference value of the initial pixel point according to a preset rule to determine the corrected image. The preset rule is that the pixelpoint with the smallest distance from the initial pixel point is determined as the target pixel point, and the brightness value and color difference value of the target pixel point are determined as the brightness value and color difference value of the pixel point mapped to the correction image by the initial pixel point. Thus, the algorithm complexity and image processing time are reduced, and the real-time signal transmission in the digital operating room is ensured.

Aspects of a method and system for bandwidth calibration for a phase locked loop are presented. Aspects of the method may include generating one or more carrier signals based on one or more corresponding calibration signals. A pre-distortion function may be computed based on the generated one or more carrier signals for the phase locked loop circuit. An output RF synthesized signal generated by the phase locked loop circuit may be modified based on the computed pre-distortion function and a subsequent output RF synthesized signal generated based on the modified output RF synthesized signal.

The invention discloses a distributed compressed forwarding system of a Gaussian source and an optimization method of the system. In the system, the source sends analog Gaussian signals, distributed compressed coding is carried out in relays, and digital transmission is carried out. A theoretical analysis frame of the system is provided by considering that reception signal to noise ratios of different relays satisfy certain proportional relation and a reception end has different receiving signal to noise ratios for different relay signals in an additive white Gaussian noise channel. For a multi-relay distributed source coding problem, a CEO theory is used to establish a rate distortion function of a multi-relay network, transmission rates of the multiple relays are obtained, a Shannon channel capacity theory is combined, the compressed transmission rates of the relay are linked to the capacity of the channel from the relays to the channel, an optimized design equation of the system is provided, and an optimal solving algorithm is provided. Under the condition that the total power is limited, power distribution is carried out between the source and the relay network based on the signal to noise ratios, and the signal to noise ratio performance of the reception end of the system is maximized.

The invention proposes a graphic image compression method, which is mainly for lossy compression of graphic images. In a traditional method, after an image is subjected to wavelet transform, an encoding method is adopted to directly encode a wavelet coefficient matrix; the compression rate of the compression method often cannot satisfy multiple images nowadays and the relationship between various pixels of the image is ignored. The method of the invention is used for modeling the relationship between an image distortion function and a bit rate function for the wavelet coefficient matrix after the wavelet transform, and the relationship between an optimal compression ratio and various pixels of the image is fully considered. The method comprises the following steps: firstly, performing three times of wavelet transform on an original image, and obtaining the wavelet coefficient matrix about the image; secondly, establishing a compression function, that is a distortion function, establishing a mathematical model of the distortion function and the bit rate function of the image in each image subblock, and then reversely substituting into the mathematical model for solving to obtain the optimized wavelet coefficient matrix under the current background; and finally, using an SPIHT encoding method to encode the optimized wavelet coefficient.

The invention discloses a novel method for compensating dead time of a converter, which is applied to universal voltage source converters. In the method, a distortion function correction step is increased on the basis of the normal method for compensating the dead time compensation. In the method, voltage feedback is used as a reference, and a dead time effect distortion function is corrected fora plurality of periods, so that the accuracy for dead time compensation can be effectively improved and the output quality of the converter is improved. The method is easy to implement and does not cause obvious disturbance to a converter control system.

The invention discloses a method of controlling rate-distortion code rate, comprising obtaining the information of the macroblock processed in the current frame; the information comprises: pixel variance yields sigmai of the macroblock i; head information Hi of the macroblock i; target bit Ri of the macroblock i; target bit Rt of the whole frame picture; the macroblock i representing the macroblock number of the current macroblock; the zero coefficient ratio and step-size are calculated according to the rate-distortion function, and the bit number of the current macroblock is controlled by the step-size. The invention further provides a device of controlling rate-distortion code rate, comprising an information unit, a calculating unit and a code rate control unit. The method and device of the invention rapidly and accurately control the data bit of each frame; the calculating process is simple, which can obtain the optimized step-size and picture quality.