132 results about "Background Correction" patented technology

A method for estimating the skeletal status or bone quality of a vertebrate on the basis of two-dimensional image data comprising information relating to the trabecular structure of at least a part of a bone of the vertebrate, the image data being data obtained by exposing at least the part of the bone to electromagnetic radiation, such as X-rays, the method comprising subjecting the image data to a statistical analysis comprising a background correction procedure in which low frequency intensity variations not related to the trabecular structure of the bone are reduced relative to image data related to the trabecular structure of the part of the bone, a feature extraction procedure comprising (a) determining values reflecting the projected trabecular density in the image data, caused by the X-ray attenuating properties of cancellous bone in the part of the bone, for each of a number of locations or areas in the image data, (b) deriving one or more features from the variation of the determined PTD-values, preferably in the longitudinal direction of the bone, and an estimation procedure in which the skeletal status of the vertebrate is estimated on the basis of the one or more derived features and optionally other features related to the bone of the vertebrate and a predetermined relationship between the features and reference skeletal status parameters. Preferably, a profile describing the projected trabecullar density as a function of the distance along a line substantially at the center of the bone is determined, and information relating to skeletal status is derived from variations, fluctuations or other features of the profile.

A chemical-sensing apparatus is formed from the combination of a chemical preconcentrator which sorbs and concentrates particular volatile organic chemicals (VOCs) and one or more chemiresistors that sense the VOCs after the preconcentrator has been triggered to release them in concentrated form. Use of the preconcentrator and chemiresistor(s) in combination allows the VOCs to be detected at lower concentration than would be possible using the chemiresistor(s) alone and further allows measurements to be made in a variety of fluids, including liquids (e.g. groundwater). Additionally, the apparatus provides a new mode of operation for sensing VOCs based on the measurement of decay time constants, and a method for background correction to improve measurement precision.

Described are computer-based methods and apparatuses, including computer program products, for monitoring, detecting, and quantifying chemical compounds in a sample. A sample measurement comprising a digitized spectroscopic profile is received. A multivariate multistage background model comprising a first model that models a first time effect, a second model that models a second time effect that is different than the first time effect, or both is calculated. A background corrected sample measurement based on the sample measurement and the multivariate multistage background model is generated. A multivariate multistage library search, fault detection, and quantification algorithm is executed to identify one or more primary chemicals in the background corrected sample measurement. The search, detection, and quantification algorithm includes identifying one or more candidate chemicals in the background corrected sample measurement based on a multivariate statistical process control and identifying and quantifying a first primary chemical based on a focused chemical evaluation of the one or more candidate chemicals.

The invention provides circuits and methods for estimating and correcting nonlinear error in analog to digital converters that is introduced by nonlinear circuit elements, for example one or more residue amplifiers in a pipelined analog to digital converter integrated circuit. In a preferred method of the invention, pseudo random calibration sequences are introduced into the digital signal to be converted by a flash digital to analog converter in one or more initial stages of the pipelined analog to digital converter circuit. A digital residue signal of the output of the one or more initial pipelined analog to digital converter stages is sampled. Intermodulation products of the pseudo random calibration sequences that are present in the digital residue signal are determined to estimate nonlinear error introduced by the residue amplifier in the one or more stages. A digital correction signal is provided to the output of the one or more stages to cancel estimated nonlinear error.

Terahertz spectroscopy methods that are fast and have excellent spectral resolution and that do not require background correction of the instrument response without sample are disclosed. In one instance, the methods include phase coherent chirp pulse generation and phase coherent detection.

A method for quantifying nitrogen-containing species from an atmospheric sample includes introducing the atmospheric sample into an NO₂-analyzer to obtain a first measurement; subjecting the atmospheric sample to thermal decomposition followed by introducing the atmospheric sample into the NO₂-analyzer to obtain a second measurement; subjecting the atmospheric sample to ozone titration and thermal decomposition followed by introducing the atmospheric sample into the NO₂-analyzer to obtain a third measurement; subjecting the atmospheric sample to excess ozone followed by introducing the atmospheric sample into the NO₂-analyzer to obtain a fourth measurement; and subjecting the atmospheric sample to a catalyst at an elevated temperature followed by introducing the atmospheric sample into the NO₂-analyzer to obtain a fifth measurement.

The invention relates to a DIBR hole filling method based on background extraction and partition recovery. First, a video sequence is utilized to rebuild a background image and a background depth image, the video sequence and a depth image sequence corresponding to the video frequence are used to compare the depth value, corresponding in all images, of all pixels, the pixel with the largest depth value is used as the pixel of the background image, a real background image and a background depth image corresponding to the background image are obtained through frame-by-frame comparison, then, a foreground image area in a picture is calculated, and finally holes in different ares are filled through different strategies. According to the method, different filling methods are used for holes in different areas, so that a reliable and real filling effect can be obtained. From experimental results, PSNR data obtained through the method are better than those of other algorithms, and structure similarity compared with real viewpoints can reach 99.1% and is improved by more than 10% than that of traditional method.

A method for deriving a background-corrected portion of a measured optical emission spectrum comprising the steps of identifying two or more background correction points from the portion of the measured emission spectrum; deriving a background correction function fitted to the identified background correction points, and applying the background correction function to the portion of the measured emission spectrum so as to produce a background-corrected portion of the emission spectrum, wherein the background correction points are identified from the measured data points by consideration of the gradients between the measured data points.

The invention discloses a microscopic image detection and recognition method for a rice blast fungus spore based on a support vector machine. The method comprises the steps of (1) image preprocessingincluding image background correction, median filtering processing and image enhancement processing, (2) image segmentation including binarization operation, morphological operation and edge detectionof a preprocessed image and the obtainment of a graph contour of a suspected rice blast fungus spore, and (3) support vector machine detection and identification including the extraction of most representative shape feature parameters and texture feature parameters from the graph contour of a suspected rice blast fungus spore, the training of a support vector machine classifier model with the shape feature parameters and texture feature parameters as input vectors, and the detection and identification of the rice blast fungus spore by using the trained support vector machine classifier model.According to the method, the rapid and accurate identification of the rice blast fungus spore can be achieved, and a technical support can be provided for the early detection and the discrimination of a disease degree of a rice blast disease.

An image copier according to the invention comprises a scanner for reading an image and a printer for forming an image on sheet, and the scanner includes a document table for positioning an original document from which an image is to be read; a document holding cover holding the original document on the original document table and having a light-emitting element for detecting the size of an original document which emits light when the size of the original document is detected, a light source for irradiating the original document with light when an image on the original document is read, a light-receiving element for image reading which receives reflected light from the original document, a controller for the light-emitting element for detecting the size of an original document which controls the light-emitting element for detecting the thickness of the original document, a specific region determination unit for identifying a specific region based on the numbers of pixels in a main scanning direction and a sub scanning direction of image data, and a background correction unit for performing a process of correcting the background of an image which has been read. In the image copier according to the invention, see-through copying of the bottom side can be suppressed by performing a background correction process after an image is read without blocking a sensor hole of a sensor for detecting the size of the original document from light.

A system and method are provided of performing background corrections for an interleaving analog-to-digital converter (ADC). An analog input signal s1(t) is accepted having a first frequency f1 and a bandwidth (BW). A clock at frequency fs creates n sample clocks with evenly spaced phases, each having a sample clock frequency of fs/2. A first tone signal s2(t) is generated at second frequency f2, outside BW. The analog input signal and the first tone signal are combined, creating a combination signal, which is sampled using the sample clocks, creating n digital sample signals per clock period 1/fs. The n digital sample signals are interleaved, creating an interleaved signal. Corrections are applied that minimize errors in the interleaved signal, to obtain a corrected digital output. Errors are determined at an alias frequency f3, associated with the second frequency f2, to obtain correction information for a rotating pair of digital sample signals.

A method for correcting the background phase in magnetic resonance phase contrast flow images includes providing a time series of velocity encoded magnetic resonance images of a patient, where the time series of velocity encoded images comprises for each time point a phase contrast image where a pixel intensity is proportional to a flow velocity, measuring a change of intensity for each pixel over the time series of phase contrast images, identifying pixels with a low measure of temporal change as stationary pixels, and calculating a correction field for the stationary pixels, where the correction field represents a background phase to be subtracted from the phase contrast image.

The invention discloses a method for automatic detection and dynamic subtraction of the stray light for a spectrometer by spectral scanning or wavelength biasing. The method comprises the following steps: firstly, a spectral scanning image of a line source for the spectrometer is obtained by adopting a single-channel or dual-channel wavelength scanning method; secondly, the spectral scanning data is processed to obtain stray light ratio data; then the stray light ratio value in the stray light subtraction formula is reset by using the obtained stray light ratio data; and finally, the dynamic subtraction is carried out on the single-channel or dual-channel stray light while the normal test is carried out on the signal received by the spectrometer. The invention has the advantages that any hardware cost is not added under the precondition without using any standard substance, and the optical spectrum instrument performs stray light automatic detection and dynamic subtraction thereof by using the spectral properties of the line source, therefore, the light precision, the linear range and the background correction capability of the atomic absorption spectrometer are greatly improved; and the background correction capability of the spectrometer can be improved to more than 100 times (1Abs) and to more than 80 times (2Abs) when the technology is applied to the high performance self-absorption background correction of the atomic absorption spectrometer.

The invention discloses an analytic method for simultaneously determining the percentage content of nine impurity elements in titanium sponge. The nine impurity elements are Sn, As, Sb, Cr, Cu, V, Ni, Zn and Nb, five types of working curve standard solutions containing the nine impurity elements are prepared through a ti-based solution and a related reference solution, under the premise of determining the working parameters of the atomic emission spectrometer of an inductively coupled plasma, scanning is respectively performed on the five types of working curve standard solutions and a to-be-detected solution of titanium sponge, related spectral lines are selected as analysis spectral lines and background correction is performed on the analysis spectral lines, all related coefficients are higher than 0.995, detection limits are all below 0.00040 percent, except several analysis spectral lines of which the relative standard deviation is below 20 percent, the relative standard deviation of other analysis spectral lines are all below 10 percent, the requirements of a common micro trace analysis are met, the method provided by the invention can meet the requirements of analysis to the percentage content of the nine impurity elements in the titanium sponge, recovery tests show that the method is feasible, and a basis for quality grade of titanium sponge is provided.

The invention discloses a laser beam width evaluation method based on moment invariance, and belongs to the field of optical measuring. According to the laser beam width evaluation method based on the moment invariance, background correction, binaryzation and median filtering processing are carried out on a collected light beam image at first to obtain a filtering image, then a zone marking is carried out on the filtering image to find an actual measurement light spot area, the center of mass and secondary moment of an actual measurement light spot are calculated, the calculated result is substituted into a formula acquired based on a moment invariance principle, and a long axis and a short axis of the light spot are calculated, namely the beam width; and finally the actual measurement light spot is framed by a rectangle adaptable to the calculated result and is displayed. The laser beam width evaluation method based on the moment invariance can not only calculate a laser spot of a regular shape, such as a round and an oval, but also calculate a laser spot of an irregular shape. Besides, the calculated result is not changed due to translation and rotation of the light spot, and reflects the inherent character of a laser beam.

The wide-range deuterium lamp background correcting system includes hollow cathode lamp, deuterium lamp, front lens, burner, back lens, monochromator, photomultiplier and signal detecting processor, as well as half-reflecting mirror, which is located in front of the front lens and driven with a stepped motor for compounding the deuterium lamp and the hollow cathode lamp. The deuterium lamp is pulse powered, and the signal detecting processor controls the stepped motor and the adjustable deuterium lamp pulse current automatically. Owing to the combination of the half-reflecting mirror and the current adjustable high strength deuterium lamp and the program controlled energy balance, the deuterium lamp background correction for atomic absorption spectrophotometer may be expanded to element Cs with longest wavelength of 852.1 nm. In addition, the system has long term high precision, high repeatability and fast correction speed.

An access control device including an electromagnetic lock module for selectively locking and unlocking a door in a door frame is provided. The access control device provides a lower profiled electromagnetic lock module to improve the aesthetics and functionality of the module, supports and integrates modern accessories such as CCTV, CCD cameras, passive motion detection with automatic background correction, digital notification display, automatic source voltage selection, door and lock status indicators, and ease of installation. The present invention further provides components and circuitry to enable connection of the electromagnetic control module to 12 or 24 volts DC or to an unfiltered rectified AC power supply.

The invention provides an automatic identification method for spectrum peak elements of a laser-induced breakdown spectrum. The automatic identification method comprises the following steps: acquiringa laser-induced breakdown spectrum to be identified and carrying out continuous background correction on the spectrum; carrying out spectrum fitting and decomposition on the spectrum, which is subjected to the background correction, by utilizing a Voigt function; constructing characteristic parameter vectors of spectrum peak signals to be identified; acquiring spectrum information of all elementsunder the same waveband of the spectrum to be identified according to a standard database, and constructing characteristic parameter vectors of the elements; carrying out similarity analysis on the characteristic parameter vector of each spectrum peak signal to be identified and the characteristic vectors of an element spectrum peak in the standard database respectively; judging that the elementcorresponding to the maximum spectrum peak in the standard database is the element belonging to the spectrum peak to be identified according to the similarity. The automatic identification method provided by the invention can be rapidly and accurately applicable to spectrum peak identification of simple and complicated spectra.