72results about How to "Solve the low measurement accuracy" patented technology

A camera layout and calibration method for improving the depth-of-field measurement precision of the invention belongs to the field of computer vision, and relates to a camera layout and depth-of-field calibration method for improving the measurement precision of cameras in the depth-of-field direction. The calibration method starts from both optimized camera layout and depth-of-field calibration, and improves the measurement precision of a vision measurement system in the depth-of-field direction. First, the baseline length and the angle between the optical axes of two cameras are determined to optimize camera layout; then, the scope of depth of field is determined according to the measurement object distance, the focusing state and the lens parameters, a calibration plate is driven by a high-precision electric control device to move between multiple positions in the depth-of-field direction of the camera, and the parameters of the binocular camera are calibrated by using multiple images of the calibration plate in each position; and during measurement, different camera parameters are selected in different positions of depth of field according to feature information to reconstruct feature 3D information. According to the invention, no prediction of the distortion model of any space in the depth of field is needed during calibration, and the robustness of calibration is improved. The calibration method has the advantages of simple process, high precision, and easy implementation.

The invention provides a circuit, method and system for time measurement. The circuit comprises a pulse generator, a first time to digital converter, a second time to digital converter and a measured value calibration unit. The pulse generator generates internal reference clock signals according to external reference clock signals under a calibration mode. The first time to digital converter is used for measuring the first code value of the external reference clock signals according to the internal reference clock signals under the calibration mode and measuring the time code value of data signals according to the external reference clock signals under a measuring mode. The second time to digital converter is used for measuring the second code value of the external reference clock signals according to the internal reference clock signals under the calibration mode. The measured value calibration unit carries out calibration on the time code value according to the first code value, the second code value and the period of the external reference clock signals. The circuit, method and system for the time measurement can improve time measurement accuracy.

The invention discloses a double-sideband distributed type optical fiber sensing system parameter measuring device. The double-sideband distributed type optical fiber sensing system parameter measuring device comprises a distributed type optical fiber sensing system based on a Brilouin optical time domain analysis (BOTDA) technology, a light orthogonal frequency division multiplexing (OFDM) signal producing module, an OFDM detecting module and a signal processing module, wherein the distributed type optical fiber sensing system comprises a first laser device, a second laser device, a first optical coupler, a first electro-optic modulator, a second electro-optic modulator, a first amplifier, a second amplifier, a pulse / random sequence generator, a circulator and a single mode optical fiber which is taken as a sensing optical fiber, and the light OFDM signal producing module comprises an OFDM signal generator, a digital-analog conversion module and a drive module. The double-sideband distributed type optical fiber sensing system parameter measuring device can improve measuring time and measuring precision, expand a measured dynamic range, and improve the reliability and the real-time performance of the distributed type optical fiber sensing system, and is suitable for long distance distributed type optical fiber sensing system parameter measurement.

The invention provides a common-light-path and multi-view-field star sensor and a star attitude measurement method thereof. The common-light-path and multi-view-field star sensor shares one set of an optical system, an imaging unit and a data processing unit, wherein the optical system can be used for simultaneously observing three fixed stars in different sky regions; the imaging unit is used for simultaneously imaging the three fixed stars in the different sky regions and carrying out star map identification on imaged star points; the data processing unit is used for carrying out extraction of center-of-mass coordinates on the collected star points of the fixed stars, carrying out non-aligned revising on offsets of three view fields and finally finishing high-precision star attitude angle output. According to the common-light-path and multi-view-field star sensor, the problem that the measurement precision of a single-view-field star sensor along an optical axis direction is low can be effectively solved; meanwhile, the disadvantages that the weight, the power consumption and the volume are great, which are caused by the reason that a traditional multi-view-field star sensor adopts an optical system and an imaging system which are split, are overcome; three-axis high-precision measurement is realized and a light miniaturized design is also realized; the requirements on the high-precision attitude measurement by multiple satellite platforms can be met.

The invention provides a distributed monocular camera laser measuring device and method for the assembling rotation angle of cylindrical parts and belongs to the technical field of precision assembly.The measuring method comprises the following steps that: a measurement coordinate system is established; two monocular industrial cameras acquire calibration images; a computer calibrates the two monocular industrial cameras; measurement parameters are set; the computer extracts the feature points of the assembling surfaces of a to-be-assembled cylindrical part A and a to-be-assembled cylindricalpart B; the computer extracts all the feature points of the assembling surface of the to-be-assembled cylindrical part A and the to-be-assembled cylindrical part B; the computer acquires an optimal pose conversion matrix and obtains the image coordinates of a pin on the assembling surface of the to-be-assembled cylindrical part A and a hole in the assembling surface of the to-be-assembled cylindrical part B; and the computer calculates an assembling angle alpha between the two to-be-assembled cylindrical parts A and B. With the measuring device and method of the invention adopted, the measuring precision of the assembling angle alpha of the cylindrical parts is effectively improved, and damage to the parts is reduced. The device and method can be used for measuring the assembling angle alpha of cylindrical parts such as a spacecraft and an underwater vehicle.

The invention discloses a scan path programming method obtained by leaf dense point cloud on the basis of laser ranging and solves the limitation of laser measurement field depth and measurement distance and the problem that the complex curve surface measurement needs the rotation axis and the measurement accuracy difference, and the noise in the front rim area and the back rim area is big. The scan path programming method comprises steps of intercepting the section couture curve of the leave shape surface, performing segmentation and extending on the section counter curve, generating a measurement path according to the segmented curve, calculating the normal angle mean value of different measurement areas as the measurement angle for measuring the leave curve surface by the laser distance measurement sensor, obtaining the dense four sheet point cloud data, unifying the four-sheet point cloud data to the same one coordinate system to obtain the complete sheet point cloud data, and performing integral optimization on the point cloud data to obtain the final high accuracy dense point cloud data. The beneficial effects are that: the invention fully utilizes the advantages that when the laser distance measurement principle head and the object to be detected form a certain angle, the measurement accuracy is not affected, front-back rim high curvature small radius area measurement is realized, the measurement accuracy is high and the speed is fast.

The invention discloses a high-precision pressure measuring system with variable reference pressure. The high-precision pressure measuring system is mainly used for wind tunnel experiment measurement,and belongs to the technical field of gas pressure measurement. The high-precision pressure measuring system provides reference pressure Pref which is close to measured pressure P through a referencepressure cavity, the reference pressure Pref is measured by means of a high-precision steady-state pressure meter, and a difference value dP between P and Pref is measured by using a small-measuring-range dynamic differential pressure sensor, namely, the measured pressure is decomposed into stable reference pressure and dynamic pressure with a small absolute value, and the stable reference pressure and the dynamic pressure are measured by means of appropriate sensors and then are re-synthesized. The high-precision pressure measuring system can satisfy requirements for response frequency of dynamic pressure measurement, has high measuring precision, solves the problem of low measurement precision of a high-frequency dynamic pressure sensor, and can adjust the reference pressure to adapt toa wide measuring range scope, so as to reduce the quantity demand of the sensors.

The invention provides a sampling method based on software frequency tracking. Non-full-period sampling is adopted, the deviation of the non-full-period sampling is decreased to be lower than a specified value, standard full-period sampling is achieved, and measurement accuracy of the non-full-period sampling is improved. The invention provides a broadband voltage / current calibration device and a broadband power / phase calibration device adopting the sampling method based on software frequency tracking. The broadband voltage / current calibration device comprises a broadband voltage / current source, a broadband resistance voltage / current divider, a sampling digital voltmeter, a signal generator and a computer, wherein the broadband voltage / current source is connected with the sampling digital voltmeter through the broadband resistance voltage / current divider, the output end of the signal generator is connected with an outer trigger port of the sampling digital voltmeter, and the computer is respectively connected with the signal generator, the sampling digital voltmeter and the broadband voltage / current source.

The invention provides a stress monitoring method of a distributed optical fiber system. The method comprises the following steps of: dividing laser into two laser beams, modulating one laser beam with pulse or a random sequence signal into pulse light, and amplifying the pulse light; modulating the other laser beam and an OFDM (orthogonal frequency division multiplexing) signal into a light OFDM signal, and amplifying the light ODFM signal; taking the amplified pulse light as pump light, and the amplified light OFDM signal is taken as detection light; performing Brillouin gain on the two kinds of light in a single mode optical fiber; performing photovoltaic conversion on the pump light and the detection light after subjected to Brillouin gain so as to obtain an OFDM electrical signal; performing channel estimation on the OFDM electrical signal so as to obtain Brillouin frequency shift of each sub-carrier; and acquiring the stress value of each point distributed along an optical fiber axial direction according to the Brillouin frequency shift of each sub-carrier. By the method, the measuring time and precision can be improved; the dynamic range can be greatly improved; the stress monitoring can be performed on power grid system equipment in real time; and the reliability and instantaneity of a distributed sensing system can be improved.

The invention discloses a method for acquiring the parasitic mismatch capacitance of an MEMS accelerometer, including the following steps: acquiring at least two preload voltages of an MEMS accelerometer during normal work and corresponding output voltages; acquiring fitting parameters according to the structure parameters, the preload voltages and the output voltages of the MEMS accelerometer; acquiring the bending amount of the mechanical beam of the MEMS accelerometer according to the structure parameters and the fitting parameters; and acquiring the parasitic mismatch capacitance of the MEMS accelerometer according to the structure parameters and the bending amount of the mechanical beam. The invention further discloses a device for acquiring the parasitic mismatch capacitance of an MEMS accelerometer. Through the process, the parasitic mismatch capacitance of the MEMS accelerometer during work is obtained. The problem that the traditional method for acquiring the parasitic mismatch capacitance has low measurement precision is solved. An effect of precise and reliable acquisition of the parasitic mismatch capacitance is achieved.

The invention provides a center distance measuring instrument for a race, which comprises a base ruler, wherein a positioning column is fixed at one end of the base ruler, and a spherical positioning contact is arranged at the top end of the positioning column; and a guide rail is fixed on the base ruler. The measuring instrument also comprises a moving ruler, wherein the moving ruler can move along the guide rail, and a connecting column is fixed on the moving ruler; and a spherical measuring contact is arranged at the upper end of the connecting column of the moving ruler and moves along the guide rail with the moving ruler through the connecting column of the moving ruler, and a retaining block can retain the moving ruler is fixed at the other end of the base ruler. The measuring instrument directly reads the displacement of the spherical measuring contact through a micrometer, and conveniently and accurately realizes the measurement of center distance of a double-race ball bearing race.

The invention provides a booster navigation and positioning solving method applicable to high-dynamic rolling reentry. The booster navigation and positioning solving method comprises the following steps: (1) establishing a high-dynamic attitude solving equation according to an optimized three-subsample equivalent rotating vector method; (2) establishing a speed and position navigation solving model of a boosting returning section according to the high-dynamic attitude solving equation established by step (1); (3) establishing an error model of an MEMS (Micro-electromechanical Systems) inertialdevice; identifying errors of the MEMS inertial device according to the speed and position navigation solving model of the boosting returning section of step (2) and boosting reentry actual measurement data, so as to obtain a revised MEMS inertial device output result; and (4) substituting the revised MEMS inertial device output result obtained by step (3) into the speed and position navigation solving model of the boosting returning section of step (2) to realize navigation and positioning solving of a boosting reentry process. The algorithm has the advantages of high solving precision, short calculation period, capability of being adaptive to large-attitude maneuvering and the like, and can provide accurate navigation position information for a booster reentry section.

The invention provides a geomagnetic total element sensor attitude error correction method, comprising: S1, measuring a geomagnetic total element sensor attitude deflection angle [alpha] and a measurement point geomagnetic field F; S2, sequentially feeding equal current in opposite directions to a first coil C1, respectively measuring deflection magnetic fields FI+ and FI-; S3, sequentially feeding equal current in opposite directions to a second coil C2, respectively, and respectively measuring the deflection magnetic fields FD+ and FD-; S4, calculating a variation correction value [delta]I'1of a magnetic inclination and a variation correction value [delta]D'1 of a magnetic declination; S5, calculating a magnetic inclination correction value I and a magnetic declination correction valueD, and a correction formula being I=I0+[delta]I'1, D=D0+[delta]D'1. The method has beneficial effects that a problem of low measurement accuracy caused by attitude changes in measurement of a geomagnetic total element sensor, so that the geomagnetic total element sensor can be applied in the fields of marine, aviation, and terrestrial measurement when attitude changes.

The invention belongs to the technical field of time measurement, and provides a time-digital converter and an error calibration device and method thereof. The error calibration method comprises the steps that the error calibration device which comprises a sampling control module, a statistic module, and a time interval calibration module is adopted, under a calibration mode, a time-digital conversion module outputs multiple calibration sampling values to the statistic module under the control of the sampling control module, and the sampling control module outputs a total number of times for sampling to the statistic module; the statistic module conducts error calibration on delay time of each delay unit in the time-digital conversion module according to the multiple calibration sampling values and the total number of times for sampling so that the time interval calibration module can calculate an interval value of time to be detected according to the sampling values and calibration data under a measurement mode, thus the measurement accuracy of the time-digital converter is improved, and the problem that the measurement accuracy of an existing time-digital converter is low due to the fact that there is difference between the delay time of each delay unit and the response speed of each trigger is solved.

The invention discloses an integrated waveform communication measurement system, and aims to provide a communication measurement system with high communication capacity and high-precision measurement.The method is realized through the following technical scheme: the method comprises the following steps that: frequency domain OFDM waveform signals are generated by all communication data generationmodules of a transmitting end and communication sub-bands 1-D; a subcarrier mapping module modulates the signals to different subband frequency domain positions through subcarrier mapping, and an IFFT module adds CP to the obtained time domain signals through a CP adding module to generate communication sub-band OFDM time domain signals; meanwhile, each measurement data generation module separately sends the time domain measurement waveform signals to the frequency spectrum shifting modules connected in series on each channel, modulates each time domain measurement waveform signal to different sub-band frequency domain positions, filters the same through each transmitting sub-band filter; and a combiner combines each filtered signal into one to realize the fusion of a communication waveform and a measurement waveform.

The invention relates to an underground electromagnetic flaw detector, and belongs to the field of oil and gas field engineering logging equipment. The underground electromagnetic flaw detector comprises a processor module, a transmitting system and a magnetic field array sensor, wherein the transmitting system and the magnetic field array sensor are connected with the processor module, and the processor module is in communication connection with each sensor in the magnetic field array sensor. During data acquisition, the processor module sends a synchronous acquisition instruction to each sensor to control each sensor to perform simultaneous acquisition. According to the invention, each sensor in the magnetic field array sensor synchronously receives sleeve electromagnetic response characteristics of different angles, and one-time transmitting and simultaneous receiving are achieved, so the single-time collecting period is shortened, the deviation between the recording starting angleand the recording ending angle of each sensor is reduced, the possibility of self-rotation of an instrument is reduced, the measurement accuracy is improved, the requirement for three-dimensional finedetection of a casing pipe is met, and the on-site logging efficiency is guaranteed.

The present invention discloses a tire impression depth data processing method, system and device. The method comprises: collecting a plurality of light bar images by projecting on a tire through a laser beam; obtaining the first coordinates of each pixel point on the light bar in each light bar image, wherein the first coordinates are a two-dimensional coordinates of each pixel point on the light bar; performing coordinate transition of the first coordinates of each pixel points to obtain second coordinates of the collection points on the tire, wherein the second coordinates are three-dimensional coordinates, and the pixel points are in one-to-one correspondence with the collection points on the tire; and determining the impression depth data of the tire according to the height dimension in the second coordinates. The problem is solved that the measurement precision of the impression depth data of tire measurement is low in prior art, and the measurement precision of the impression depth data of tire measurement is improved.

The invention belongs to the technical field of radian measurement, and provides a touch screen glass membrane radian measurement method and system. The radian measurement method comprises the following steps that A. film projection is performed on the standard designed radian, and a first arc is generated; B. the radian cross section of a touch screen glass membrane is amplified and projected to a projector, and a second arc is generated; C. alignment and correction are performed on the first arc and the second arc, and the radian difference of the first arc and the second arc is calculated; and D. whether the radian of the touch screen glass membrane meets the requirements is judged according to the radian difference of the first arc and the second arc. With application of the radian measurement method, whether the radian of the touch screen glass membrane meets the requirements is judged according to the radian difference of the first arc and the second arc; and whether the second arc deviates relative to the first arc is directly seen with the naked eyes so that whether the radian of the touch screen glass membrane meets the requirements can be further verified, and the effect of accurately measuring the radian of the touch screen glass membrane can be realized.

The invention discloses a vertical single-optical-element rotary Mueller matrix imaging measuring device and method and belongs to the technical field of polarization optical measurement and micro imaging. The device comprises a light source, a reflector, a polarization modulation unit, a sample measurement unit, a polarization demodulation unit, an optical detector and a calculator which are sequentially arranged along a light path. The device is characterized in that the Stokes-Mueller calculus principle is utilized to establish the relationship between a to-be-measured sample and changing light intensity measured by the optical detector, a Mueller matrix imaging measuring device is adopted to measure a full Mueller matrix of the to-be-measured sample so that all optical anisotropy parameters of the to-be-measured sample are further obtained. The device is advantaged in that problems of complex operation, low measurement precision and the like in the processes of measurement, transformation solution and the like of a polynomial Fourier coefficient are solved, so the measurement speed and precision are improved, and non-destructive, quick and accurate measurement of the structuralmorphology and optical anisotropy parameters of the sample can be realized.

The invention provides an insulating sleeve surface charge measuring device and system. The insulating sleeve surface charge measuring device comprises a supporting mechanism, a position adjusting device and a measuring device body; the supporting mechanism is used for being connected with a to-be-measured insulating sleeve; the measuring device body is used for measuring the surface charge amountand charge distribution of the to-be-measured insulating sleeve; the position adjusting device is arranged on the supporting mechanism, connected with the measuring device body and used for adjustingthe position of the measuring device body so that the measuring device body corresponds to all positions of the to-be-measured insulating sleeve. According to the insulating sleeve surface charge measuring device and system, the position of the measuring device body is adjusted through the position adjusting device so that the measuring device body can correspond to any position of the surface ofthe to-be-measured insulating sleeve, the measuring device body can measure the charge amount at any position on the surface of the to-be-measure insulating sleeve conveniently, the overall measurement of the surface charge amount of the insulating sleeve is achieved, the accuracy of measurement is effectively improved, and therefore the distribution of an electric field on the surface of a highvoltage sleeve can be accurately understood.

The invention relates to a method for realizing high-precision measurement of a residual current. The method comprises the following steps that 1, the relationship between a secondary sensing voltagevalue detected by a transformer and an AD sampling value of a single-chip microcomputer is acquired; 2, a relationship is obtained through a cubic polynomial curve fitting by utilizing the secondary sensing voltage value detected by the transformer historically and the primary residual current value corresponding to the secondary sensing voltage value; 3, the secondary sensing voltage value of therelationship established in the step 2 is replaced by the AD sampling value, and the relationship between the AD sampling value and the primary residual current value is obtained; 4, the single chipmicrocomputer obtains the real-time primary residual current value according to the acquired AD sampling value; and 5, after the primary residual current value is obtained, determination is carried out, and the problem that the measurement precision is low due to the fact that the small-size residual current transformer measurement cannot be realized in a small intelligent switch system is solvedthrough the digital curve fitting method.

The invention is applicable to the technical field of image processing, and provides a pupil distance measurement method and device, terminal equipment and a storage medium, and the method comprises the steps: obtaining an image including two eyes; extracting pupil center image coordinates of the two eyes according to the images; and calculating the pupil distance between the two eyes according tothe pupil center image coordinates. According to the pupil distance measurement method and device, the terminal equipment and the storage medium, pupil center image coordinates of two eyes in the two-eye image are extracted by using a digital image processing technology; compared with a traditional method of directly measuring the pupil distance through a calibrated scale, the pupil distance measurement precision is greatly improved, the pupil distance measurement precision can be improved to the pixel level, namely, the micron order of magnitude, and the problem that the measurement precision is low in existing double-eye pupil distance measurement is solved.

The invention belongs to the technical field of a time digital converter and provides a time digital converter, an error correcting device and an error correcting method. In the invention, the error correcting device which comprises a control module, a storage module, a calculation module and a correcting module is adopted; the control module is used for respectively outputting a start pulse signal, a first stop pulse signal and a second stop pulse signal at a first rising edge, a second rising edge and a third rising edge of a reference clock signal; the time digital converter is used for outputting a first time measured value and a second time measured value according to the three pulse signals; the storage module is used for storing the first time measured value and the second time measured value; the calculation module is used for calculating a gain error and an offset error of the time digital converter according to the two time measured values; the correcting module is used for correcting the errors of the time measured values of the time digital converter according to the gain error and the offset error. The problem of low measurement precision caused by Gain error and Offset error of the present TDC can be solved.

The invention relates to an ultrasonic distance measuring technology, in particular to an ultrasonic distance measuring method and device based on multiple emission frequencies. The problem that an existing ultrasonic distance measuring technology is low in measuring precision is solved. The ultrasonic distance measuring method includes the steps that ultrasonic pulse signals are emitted and received within a measurement period, wherein the emitted ultrasonic pulse signals are eight ultrasonic pulse signals of different frequencies; timekeeping is started when the ultrasonic pulse signal of each frequency is emitted; timekeeping is stopped when echo signals of corresponding frequencies are received; in this way, at most eight time values are obtained, an arithmetic mean value of the time values is obtained, then a calculation value t0 of ultrasonic pulse signal propagation time within the measurement period is obtained and brought into the formula s=170t0, and finally the distance s from an object to be measured is obtained. The method and device are high in distance measuring precision. According to the technical scheme, the ultrasonic distance measuring method and device are novel and unique in design and suitable for various distance measuring fields.

The invention discloses a temperature monitoring method of a distributed optical fiber system. The method includes: dividing laser into two laser beams, modulating one laser beam with pulse or random sequence signals to obtain pulsed light, and amplifying the pulsed light; modulating the other laser beam with OFDM (orthogonal frequency division multiplexing) signals to obtain optical OFDM signals, and amplifying the optical OFDM signals; using the amplified pulsed light as pumping light, and using the amplified optical OFDM signals as probe light; subjecting the pumping light and the probe light to Brillouin gain in a single mode fiber; performing photovoltaic conversion to the pumping light and the probe light subjected to Brillouin gain to obtain OFDM electrical signals; performing channel estimation to the OFDM electrical signals to obtain Brillouin frequency shift of each subcarrier; and obtaining temperature of points distributed along an optical fiber shaft according to the Brillouin frequency shift of each subcarrier. By the method, measuring time can be shortened, measuring precision can be increased, dynamic range can be increased greatly, power grid system temperature can be monitored in real time, and reliability and instantaneity of a distributed sensing system can be improved.

The invention relates to a technology for measuring the rolling angle rate of a rotating missile, and concretely relates to a multi-sensor data fusion-based rolling angle rate high-precision measurement method. The problem of low measurement precision of an active semi-strapdown inertia measurement system for measuring the rolling angle rate of a rotating missile is solved in the invention. The multi-sensor data fusion-based rolling angle rate high-precision measurement method comprises the following steps: 1, defining a carrier coordinate system; 2, mounting a wide-range gyroscope in the outer cylinder of the active semi-strapdown inertia measurement system, mounting a medium-range gyroscope at the top of MIMU of the active semi-strapdown inertia measurement system, and mounting a small-range gyroscope in the MIMU of the active semi-strapdown inertia measurement system; 3, calculating relative rotating speed data between the outer cylinder and an inner cylinder; 4, reproducing missile rolling angle rate data; and 5, using the reproduced missile rolling angle rate data as a control signal. The method is suitable for measuring the rolling angle rate of the rotating missile.

The invention provides a high-end sampling battery voltage circuit which comprises a battery end voltage acquisition circuit and an equivalent measurement circuit. The battery end voltage acquisition circuit is connected with the equivalent measurement circuit, the battery end voltage acquisition circuit is used for obtaining voltage of a battery to be measured, and the equivalent measurement circuit is used for distance measurement for the obtained voltage of the battery to be measured. According to the technical scheme of the high-end sampling battery voltage circuit, defects in the prior art are overcome, the problem of low measurement precision caused by a voltage difference generated by non-common-ground link between the battery and an MCU is ingeniously resolved, the requirement of the voltage sampling circuit for precision is not high, good measurement precision can be obtained by means of a common main control chip with an ADC, and cost of products is greatly reduced.

The invention discloses a scan path programming method obtained by leaf dense point cloud on the basis of laser ranging and solves the limitation of laser measurement field depth and measurement distance and the problem that the complex curve surface measurement needs the rotation axis and the measurement accuracy difference, and the noise in the front rim area and the back rim area is big. The scan path programming method comprises steps of intercepting the section couture curve of the leave shape surface, performing segmentation and extending on the section counter curve, generating a measurement path according to the segmented curve, calculating the normal angle mean value of different measurement areas as the measurement angle for measuring the leave curve surface by the laser distance measurement sensor, obtaining the dense four sheet point cloud data, unifying the four-sheet point cloud data to the same one coordinate system to obtain the complete sheet point cloud data, and performing integral optimization on the point cloud data to obtain the final high accuracy dense point cloud data. The beneficial effects are that: the invention fully utilizes the advantages that when the laser distance measurement principle head and the object to be detected form a certain angle, the measurement accuracy is not affected, front-back rim high curvature small radius area measurement is realized, the measurement accuracy is high and the speed is fast.

The embodiment of the invention provides an altitude measurement method and electronic equipment, and relates to the technical field of positioning and navigation. The method comprises the following steps: 1, when the electronic equipment is located at the first position, the altitude corresponding to the first position is obtained through a navigation positioning device and an electronic map, andwhen the electronic equipment moves from the first position to the second position, the altitude corresponding to the second position is obtained according to the altitude corresponding to the firstposition and the sensor data measured by the sensor. According to the scheme, the altitude measurement precision can be improved. In addition, the hardware cost of the electronic equipment does not need to be increased, and the universality and the practicability of the scheme are guaranteed.

The invention provides a circuit, method and system for time measurement. The circuit comprises a pulse generator, a first time to digital converter, a second time to digital converter and a measured value calibration unit. The pulse generator generates internal reference clock signals according to external reference clock signals under a calibration mode. The first time to digital converter is used for measuring the first code value of the external reference clock signals according to the internal reference clock signals under the calibration mode and measuring the time code value of data signals according to the external reference clock signals under a measuring mode. The second time to digital converter is used for measuring the second code value of the external reference clock signals according to the internal reference clock signals under the calibration mode. The measured value calibration unit carries out calibration on the time code value according to the first code value, the second code value and the period of the external reference clock signals. The circuit, method and system for the time measurement can improve time measurement accuracy.