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1327 results about "Length measurement" patented technology

Length measurement is implemented in practice in many ways. The most commonly used approaches are the transit-time methods and the interferometer methods based upon the speed of light. For objects such as crystals and diffraction gratings, diffraction is used with X-rays and electron beams. Measurement techniques for three-dimensional structures very small in every dimension use specialized instruments such as ion microscopy coupled with intensive computer modeling.

Closed loop congestion control using a queue measurement system

A queue length measurement device that is comprised of a number of queues that are capable of holding data cells. A differential counter is coupled to each queue. The counter is incremented when a cell is written into the queue and decremented when a cell is read from the queue. An interval measurement device, coupled to the differential counter, generates a pulse to reset the counter at fixed intervals equivalent to n cells time (where n is the maximum number of cells the queue counter can measure). A multiplexer is coupled to the multiple differential counters. A transfer control circuit coupled to the interval measurement device selects the appropriate queue measurement to be output from the multiplexer to the other switch elements. A system and methodology provide for queue flow statistics and closed loop control of cell flow into the queue. A congestion control system is provided comprising a queue (having an input and an output, and capable of storing and outputting a plurality of data cells), an input processor (for coupling a plurality of data cells to the queue input), an output processor, an interval measurement device (generating a pulse at predetermined intervals), and differential queue length generation logic. The output processor, couples to the queue output, for receiving a plurality of data cells from the queue, which generates a queue change in size signal in response to determining for each of the predefined intervals of the difference between a present and a previous queue length.
Owner:WHITTAKER COMM

Dynamic crack length measurement method for machine vision fatigue crack propagation test

The invention provides a dynamic crack length measurement method for a fatigue crack propagation test based on the machine vision technology. The method comprises the following steps: 1, performing machine vision crack measurement system calibration; 2, performing fatigue test, wherein a test piece with precracks begins to generate fatigue cracks along the direction of the precracks, and the fatigue cracks extend; 3, collecting crack images, wherein a mode of collecting single-face images of the test piece and a mode of collecting two-side images of the test piece are used in the fatigue crack propagation test; 4, reinforcing the collected images; 5, identifying the position of the trunk of cracks, as well as peaks and identifying directions of cracks by using the method of image analysis and crack identification; and 6, calculating the actual crack identifying length and crack length. The method has the advantages of simplifying the process and reducing work load; and by the method, the crack identifying process can be visually and accurately observed and recorded, the calculated crack length specified by the international standard can be measured accurately. The method also has the advantages of high measurement accuracy and good system anti-jamming performance.
Owner:平邑经济开发区投资发展有限公司

Full automatic pipe cutting machine

The invention discloses a full automatic pipe cutting machine. The pipe cutting machine comprises a feeding drive part, a cutting drive part, a pipe clamping part, a cutting part, an unloading part and a cutting measurement part which are sequentially arranged on an operating platform, wherein the feeding drive part conveys pipes to the cutting part by a driving wheel and a rolling wheel, then the pipes are cut off by a cutting tool driven by the cutting drive part; the driving wheel of the pipe cutting machine is driven by a stepping motor, and the lengths of the cut pipes can be accurately detected and controlled according to the electrical signals of stepping quantity of the stepping motor and the data of radius of the driving wheel; and in addition, the operating platform is also provided with an infrared distance measurement sensor, and the length accuracy of the cut pipe is jointly ensured by the electrical distance measurement signals and the movement detection signals of the stepping motor. By adopting the clamping feeding structure, the automatic cutting structure, the automatic clamping structure, the automatic unloading structure and the automatic cut pipe-length measurement and control mechanism, the degree of automation of the pipe cutting machine is improved.
Owner:中臻工业有限公司

High steel level petroleum casing pipe and oil pipe manufacturing process

The invention discloses a preparation method of high-grade steel petroleum casing pipes and oil pipes, and relates to a manufacturing method of petroleum casing pipes and oil pipes; hot rolled steel coils are taken as raw material for manufacturing the steel pipes, and ERW welded pipe material is firstly manufactured by the processes such as longitudinal-shearing striping, band steel formation, high-frequency welding, burr cleaning inside and outside of the welding seams, welding seam detection, intermediate-frequency welding seam annealing, sizing, cutting off, straightening and the like; and the processes such as post-welding finishing, end upsetting (heavy wall tubing needs the process), integral hardening and tempering, medium-temperature straightening, pipe end detection, pipe threading processing, collar screw coupling, hydraulic pressure test, path test, pipe body detection, length measurement, weighting, oiling and the like are carried out, thus producing the high-grade steel petroleum casing pipes and oil pipes. The steel grade of the steel pipe can reach the steel grade specified in API 5CT standard for manufacturing N80Q, L80, C95, P110 and Q125 with a welding method. The high-grade steel petroleum casing pipes and oil pipes manufactured by the invention has the advantages of high production efficiency, low production cost, high lumber recovery, and high product quality.
Owner:江苏嘉宝科技制管有限公司

Measuring method for length, width and height of vehicle based on RGB-D camera

The invention discloses a measuring method for length, width and height of a vehicle based on an RGB-D camera. The method comprises the steps of acquiring a clear vehicle image in a camera short-distance mounting manner, calibrating the camera according to a calibrating method based on a disappearing point, obtaining an internal parameter and an external parameter of the camera, realizing three-dimensional point cloud conversion of a vehicle target in a world coordinate system through a camera depth image solution, and acquiring three-dimensional coordinate information of the external surfaceof the vehicle; acquiring the three-dimensional coordinate of the external surface of the vehicle by means of prior knowledge and an image processing method, splicing a vehicle image according to sequence patterns in a vehicle motion process through a registering method, and realizing three-dimensional measurement to the profile of the vehicle. The measuring method overcomes defects of high equipment requirement and tedious operation in a traditional method and realizes high calibration precision. The actual displacement of the vehicle is comprehensively analyzed through a matching relation ofpoints which correspond with the same position of the vehicle in the image sequence, thereby realizing relatively high registering precision. The measuring method further has advantages of realizingaccurate splicing of the vehicle side surfaces, reducing vehicle length measurement error and improving accuracy in splicing the vehicle side surfaces.
Owner:CHANGAN UNIV

Vehicle queue length measurement method based on PTZ (Pan/Tilt/Zoom) camera fast calibration

The invention discloses a vehicle queue length measurement method based on PTZ (Pan/Tilt/Zoom) camera fast calibration. The vehicle queue length measurement method based on the PTZ camera fast calibration comprises the following steps of choosing two vertically-crossed traffic markings to form a T-shaped scaling reference and establishing a conversion relation between coordinates of pixels in an image and coordinates of roadway corresponding points in a world coordinate system according to the defined models of the image coordinate system and the world coordinate system; acquiring video images of a traffic monitoring scene by adopting a PTZ camera, setting an ROI (Region Of Interests) of a lane, detecting the vehicle queue state in the ROI by the adoption of an adaptive background update algorithm and textural features, and acquiring the pixels and pixel coordinates of the tails of the vehicle queues; converting the detected pixel coordinates of the tails of the vehicle queues into the world coordinate and finally computing the length of the vehicle queues. The tail position of the vehicle queues is judged according to the textural features, and the measurement of length of the vehicle queues is finished by the combination of the camera, so that the vehicle queue length measurement method based on the PTZ camera fast calibration, disclosed by the invention, has the advantages of low cost, strong embedded type, and the like.
Owner:HUNAN UNIV +1

Pulse run-length measurement for HF data signal by dividing accumulated phase difference between first and second zero-crossings by single-cycle range using multiple cycle range sawtooth waveform

A system and method for accurately measuring a pulse run length in a high frequency (HF) data signal while utilizing a low analog-to-digital conversion (ADC) sampling rate. Four bits are added to the most significant end of an oscillator's accumulator register so that the oscillator generates a sawtooth clock waveform ranging in phase from zero (0) to 32pi radians. An interpolator detects a first zero-crossing transition of the HF data signal at the leading edge of the pulse run length, and a phase detector measures a first phase increment at that time. The MSBs of the accumulator register is then initialized to place the measured first phase increment in a range between zero (0) and 2pi radians. The accumulator register then accumulates phase increments until the interpolator detects a second zero-crossing transition of the HF data signal at the trailing edge of the pulse run length, and the phase detector measures a second phase increment when the second zero-crossing transition is detected. An accumulated phase difference is calculated by subtracting the initialized first phase increment from the measured second phase increment. The pulse run length is then obtained by dividing the accumulated phase difference by 2pi.
Owner:CEVA IRELAND +1

Device and method for measuring micro-pore size based on fiber Bragg grating

The invention provides a device and method for measuring a micro-pore size based on a fiber Bragg grating and belongs to the technical fields of precision instrument manufacture and precision test metering. The device consists of an aiming and signaling device for generating aiming signals, a length measuring device for measuring the movement distance of a micro-pore to be measured within a time interval of measuring measurement starting and stopping signals which are sent by the aiming and signaling device, and a computer for controlling a measurement process of the entire measuring device. The method comprises the following steps of: continuously moving a working table along a direction vertical to a length measurement direction, and moving the working table along a measurement line to obtain a maximum displacement, relative to the micro-pore to be measured, of a probe, so as to obtain the diameter of the micro-pore to be measured. According to the device and method disclosed by the invention, the adaptability of the aiming and signaling device to the environment is greatly improved. The device disclosed by the invention has the characteristics of simple structure, good real-time capability and easiness for actual application, and has obvious advantage of carrying out rapid and ultra-precise measurement and aiming on the size of the micro-pore.
Owner:HARBIN INST OF TECH
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