101 results about "Calibration free" patented technology

A system and method for eye gaze tracking in human or animal subjects without calibration of cameras, specific measurements of eye geometries or the tracking of a cursor image on a screen by the subject through a known trajectory. The preferred embodiment includes one uncalibrated camera for acquiring video images of the subject's eye(s) and optionally having an on-axis illuminator, and a surface, object, or visual scene with embedded off-axis illuminator markers. The off-axis markers are reflected on the corneal surface of the subject's eyes as glints. The glints indicate the distance between the point of gaze in the surface, object, or visual scene and the corresponding marker on the surface, object, or visual scene. The marker that causes a glint to appear in the center of the subject's pupil is determined to be located on the line of regard of the subject's eye, and to intersect with the point of gaze. Point of gaze on the surface, object, or visual scene is calculated as follows. First, by determining which marker glints, as provided by the corneal reflections of the markers, are closest to the center of the pupil in either or both of the subject's eyes. This subset of glints forms a region of interest (ROI). Second, by determining the gaze vector (relative angular or Cartesian distance to the pupil center) for each of the glints in the ROI. Third, by relating each glint in the ROI to the location or identification (ID) of a corresponding marker on the surface, object, or visual scene observed by the eyes. Fourth, by interpolating the known locations of each these markers on the surface, object, or visual scene, according to the relative angular distance of their corresponding glints to the pupil center.

A method and computer system for tracking eye gaze. A camera is focused on an eye of subject viewing a gaze point on a screen while directing light toward the eye. Eye gaze data pertaining to a glint and pupil image of the eye in an image plane of the camera is sampled. Eye gaze parameters are determined from the eye gaze data. The determined eye gaze parameters include: orthogonal projections of a pupil-glint displacement vector, a ratio of a major semi-axis dimension to a minor semi-axis dimension of an ellipse that is fitted to the pupil image in the image plane, an angular orientation of the major semi-axis dimension in the image plane, and mutually orthogonal coordinates of the center of the glint in the image plane. The gaze point is estimated from the eye gaze parameters.

The present invention provides a Positioning on One Device (POD) for locating and tracking objects and an autonomous ultrasound indoor track system (AUITS) and method for locating objects by using the POD. The AUITS can comprise: a tag device installed on a mobile object, which includes radio frequency (RF) and ultrasound transmitters for transmitting RF and ultrasound signals; and a POD for receiving the RF and ultrasound signals transmitted from the tag device to locate the mobile object. The POD can comprise: a plurality of leaf modules, each of the leaf modules including a positioning signal receiver for receiving the positioning signals (e.g. ultrasound signal) transmitted from the tag device, wherein there is a known structural topology relationship between the plurality of leaf modules. Then, the positioning signal detection times from respective positioning signal receivers and the structural topology relationship of the POD can be used for calculation of the position of the object. Compared with the prior arts, the POD and the AUITS system of the present invention presents several advantages, such as high accuracy, easy deployment, calibration free, low cost, in-device coordination, and flexibility.

A method and device for eye gaze estimation with regard to a sequence of images. The method comprises receiving a sequence of first video images and a corresponding sequence of first eye images of a user watching at the first video images; determining first saliency maps associated with at least a part of the first video images; estimating associated first gaze points from the first saliency maps associated with the video images associated with the first eye images; storing of pairs of first eye images/first gaze points in a database; for a new eye image, called second eye image, estimating an associated second gaze point from the estimated first gaze points and from a second saliency map associated with a second video image associated with the second eye image; storing the second eye image and its associated second gaze point in the database.

The invention discloses a two-node measuring equipment unrelated quantum key distribution system. Two independent laser devices and a measuring device Charlie are all placed on the same node, namely an Alice end or a Bob end to form the two-node bidirectional transmission quantum key distribution system. According to the system, a two-node structure is adopted, the Faraday conjugated rotation effect is utilized, and the same transmission path is designed; as a result, the problem that an existing three-node measuring equipment unrelated quantum key distribution system is poor in stability due to polarization change, phase drift, non-uniform phase reference systems, time jitter and other factors is effectively solved, the purposes of polarization self-compensation, phase drift self-compensation, calibration-free phase reference systems and easy synchronization are achieved, and an important basis is provided for practical application of the measuring equipment unrelated quantum key distribution system.

The invention relates to a method of gaze estimation. As to determine the position of the gaze without calibrating the system used for determining the gaze, the method comprises: detecting at least a location of the centre of at least an eye on at least an eye image of a viewer watching at least a video image displayed on a screen; determining at least a first position of the gaze of the viewer on the screen by using the at least a detected location of the centre of the at least an eye and a mapping function based on centre-bias property of human gaze distribution. The invention also relates to a device configured for estimating the gaze.

The invention relates to a near field communication method and system. The method comprises the following steps: a card reader emits a low-frequency alternating magnetic field signal of which the frequency is equal to or less than the highest frequency f0 for the calibration-free work of a system, and the signal carries identity identification information; a mobile radio frequency device receives and detects a low-frequency signal and amplifies the low-frequency signal into a voltage signal to judge whether a terminal enters an effective-distance zone; if the voltage signal is more than or equal to voltage threshold Vt, the terminal enters an effective card swiping zone to obtain the identity identification information of the card reader, the identity identification information of the terminal and the identity identification information of the card reader are simultaneously transmitted to the card reader via a radio frequency channel; the card reader receives the transmitted information and compares whether the identity identification information in the information is identical with the self identity identification information; and if yes, the card reader carries out card swiping transaction with the radio frequency channel. According to the method and the system, data communication distance between the radio frequency communication terminal containing the mobile radio frequency device and the card reader is reliably controlled with a specified range, and the terminal does not need to be calibrated.

The invention relates to a mobile radio frequency device, a radio frequency IC (Integrated Circuit) card and a radio frequency storage card, wherein the mobile radio frequency device comprises at least one low-frequency magnetic induction circuit, at least one low-frequency amplifying circuit, at least one threshold judging and demodulating circuit, at least one second main processor, at least one radio frequency transceiver circuit and at least one radio frequency antenna, wherein the low-frequency magnetic induction circuit, the low-frequency amplifying circuit, the threshold judging and demodulating circuit, the second main processor, the radio frequency transceiver circuit and the radio frequency antenna are sequentially connected in series; and a low-frequency receiving link formed by the low-frequency magnetic induction circuit, the low-frequency amplifying circuit and the threshold judging and demodulating circuit works at the frequency below the highest frequency f0 of the calibration-free work of a previously selected system. The mobile radio frequency device can ensure that a mobile terminal provided with the mobile radio frequency device realizes card swiped transactions, i.e. electronic payment and the like.

A method of calibration-free scanned-wavelength modulation spectroscopy (WMS) absorption sensing is provided by obtaining absorption lineshape measurements of a gas sample on a sensor using 1/-normalized WMS-2/j where an injection current to an injection current-tunable diode laser (TDL) is modulated at a frequency ̂ where a wavelength modulation and an intensity modulation of the TDL are simultaneously generated, extracting using a numerical lock-in program and a low-pass filter appropriate band-width WMS-<</ (n=1, 2, . . . ) signals, where the WMS-<</ signals are harmonics of the f, determining a physical property of the gas sample according to ratios of the WMS-<</ signals, determining the zero-absorption background using scanned-wavelength WMS, and determining non-absorption losses using at least two the harmonics, where a need for a non-absorption baseline measurement is removed from measurements in environments where collision broadening has blended transition linewidths, where calibration free WMS measurements without knowledge of the transition linewidth is enabled.

A circuit for producing multiple switching control signals for a harmonic rejection mixer from multiple phases of a digital local oscillator signal is presented, wherein a first waveform combiner circuit is arranged to generate from the multiple phases of the digital local oscillator signal at least one switching control signal by logical combining two from the multiple phases of a digital local oscillator signal, and a second waveform combiner circuit is arranged to generate from the multiple phases of the digital local oscillator signal at least one first switching control signal by logical combining one from the multiple phases of a digital local oscillator signal with a predetermined signal having a static logical value. To compensate for phase errors the schematic topology of the first and the second waveform combiner circuit are arranged to be fully symmetrical to each other in that in the first waveform combiner, the circuit part for providing the function of the second waveform combiner is used as a dummy circuit, and in the second waveform combiner, a circuit part for providing the function of the first waveform combiner is used as a dummy circuit. Accordingly, the sources for providing the multiple phases of the digital local oscillator signal see the same load, and hence required phase shift is guaranteed.

The invention provides a calibration-free and convenient monocular lens fisheye image distortion correcting method. The method is characterized by being divided into the following steps: 1) marking out three correction mark points on an image for the single image or a certain frame of the image in a video acquired by a monocular camera; 2) according to the distortion characteristics of the image,constructing a fisheye distortion correction calculation model; 3) subjecting the correction mark points to data optimization to eliminate the error and improve the robustness of the correction algorithm; 4) carrying out numerical solution on the distortion correction calculation model by applying the optimized correction mark points, and reversely solving fisheye distortion parameters; 5) carrying out image correction according to the fisheye distortion parameters, and calculating the pixel value of each point on the corrected image, wherein the fisheye distortion parameters only need to be solved once. According to the correction technology, the parallel treatment on all pixels of the image is not required, while all frames of the image in the video are subjected to parallel treatment. Therefore, the technology is also suitable for the real-time fisheye distortion correction of videos.

The invention discloses a calibration-free gas parameter measurement method based on triangular wave modulation. The method comprises the following steps: superimposing a high-frequency triangular wave signal on a scanning signal and establishing a time-frequency response model of a DFB (Distributed Feedback) laser device based onfor such a modulation manner; simplifying a triangular wave modulation waveform into a form of superimposing a plurality of sine waves; extracting all parameters of the model through fitting an etalon signal. Based on the model, calibration-free measurement of gas concentration is realized. Compared with a traditional sine modulation manner, a modulation method provided by the invention can be used for remarkably improving the signal-to-noise ratio of a measurement system; furthermore, compared with other triangular wave modulation methods, the calibration-free gas parameter measurement method provided by the invention does not need to be used forhas no need of calibrating by utilizing standard gas and is more suitable for measurement of gas parameters under a severe environment.

The invention belongs to the technical field of laser spectroscopy, and mainly relates to a calibration-free wavelength modulation spectroscopy gas detection method based on an S[2f] method. Corresponding scientific analysis shows that A, i[1], i[2], concentration and phase difference psi[1] and psi[2] have little influence on S[2f]/S[2f]<c> signals, and only WMRF has obvious influence on the S[2f]/S[2f]<c> signals. Therefore, under conditions of uncertain concentration and phase shift, WMRF is obtained by inverting the S[2f]/S[2f]<c> signals, and because fitting parameters are greatly reduced, the method can be guaranteed to be simple, rapid and accurate. On the basis, the concentration of to-be-measured gas is fitted, and a measurement value with higher accuracy degree is obtained. The new method is simple, rapid and accurate, and is suitable for wide promotion in the field of gas detection.

In order to accurately determine the location of an electronic device in an environment, a computer selects a set of received-signal-strength (RSS) values based on wireless communication between the electronic device and access points in sub-regions of the environment. This set includes a largest RSS value associated with a sub-region and at least two RSS values associated with neighboring sub-regions. Then, the computer calculates pairwise distance estimates of the location of the electronic device in the environment based on predefined locations of the access points associated with the set, one or more differences of pairs of RSS values in the set and a predetermined path-loss factor in the environment, where a given pair of RSS values includes the largest RSS value and one of the at least two RSS values. Furthermore, the computer determines the location of the electronic device in the environment based on the pairwise distance estimates.

The invention relates to a disassembling and assembling calibration-free method for inertial elements of a strapdown inertial navigation system. The disassembling and assembling calibration-free method for the inertial elements of the strapdown inertial navigation system comprises reference for installation of degree of freedom of a gyroscope 3, reference for installation of degree of freedom of an accelerometer 3, reference for installation of IMU, installation of the inertial elements, calibration of the inertial navigation system, equation for element inertia measurement errors caused by installation errors and backstepping of the precision of the navigation system to requirements for the installation errors. The design thought of the achievement of the invention is novel, and has innovativeness, repeatability of the installation errors for the inertial elements is ensured, the repeated installation errors are controlled in a negligible range, therefore, a disassembling and assembling calibration-free function of the inertial elements is fulfilled, the maintainability of the system is improved, the inertial elements of the strapdown inertial navigation system can be maintained in the external field and do not need to return to a factory for calibration.

The present invention provides a system and method for achieving a calibration-free primary atomic clock standard operating at the 0-0 transition free-atom frequency, thus creating a primary frequency standard, with attributes that include scalable to chip-scale dimensions and power consumption.

The invention belongs to the technical field of laser spectroscopy, in particular relates to a WMRF new model-based calibration-free wavelength modulation spectrum gas detection method, and solves the technical problem of low precision of a calibration-free wavelength modulation spectrum technology currently used for gas concentration detection. An etalon of a 0.02 cm<-1> free spectral range is used to analyze wavelength change WMRF caused by signal modulation, a first harmonic component with the amplitude linearly changed and a second harmonic component with an amplitude as a constant are observed, and a new model for describing WMRF is described. By using the new model, a system can acquire a more accurate fitting result; compared with a conventional system, hardware module addition and manual operation are not needed, only program improvement is needed, and development and application are facilitated. The method is simple in technical scheme and convenient in operation, consumption of lots of manpower and material resources is not needed, and the cost and convenience degree in use are easily accepted by most application departments.

The present invention relates to a calibration-free fast-neutron water content measuring method. Said method utilizes fast-neutron and gamma-ray to simultaneously on-line detect water content and bulk density of material on the conveyer band. The bulk density measurement adopts gamma-ray transmission method, the parameter for measuring bulk density can be used to make correction of water content value measurement. Said invention also provides the concrete steps of said measuring method and its application range.

An embodiment of the invention discloses a calibration method for a capacitor mismatch error of a pipeline ADC (analog to digital converter). On the basis of the calibration-free structure of the traditional pipeline ADC, a calibration level with the capacitor mismatch error required to be calibrated is composed of a level MDAC (multiplying digital to analog converter) structure and a level-calibrated switch structure, and meanwhile, a capacitor mismatch error digital calibration circuit is added. During the calibration-level capacitor error extracting period, two special inputs are supported by the level-calibrated switch structure to a calibration-level sampling capacitor to obtain two digital codes containing the capacitor mismatch errors, and accordingly digital calibration is performed by extracting the calibration-level capacitor mismatch error. The calibration method is simple in structure, fewer additional elements are required, sequential control is easy, and the problem that poor static characteristics, caused by capacitor mismatch, is calibrated is solved.