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This gauge was designed on the basis of a double-sided printed circuit board, which was used for forming its sensitive elements, capacitive reference gauge blocks, as well as all communication lines by the photolithography method with a high accuracy. Each meter of this level gauge is divided into eight continuous measurement sub-bands, ending with a reference gauge block, due to which an auto-calibration of each measurement sub-band with an absolute error of Δ = ±0.3 mm is carried out. An accuracy control with the help of reference gauge blocks is carried out in each measurement cycle evenly throughout the whole range of level measurement of the controlled liquid. A technique has been developed for designing a discrete-continuous capacitive level gauge for a wide class of dielectric liquids with complex manufacturing of sensitive elements and gauge communication lines based on a one-meter printed circuit board. A simple design of the level gauge and manufacturing of sensitive elements in the form of printed circuit boards, and the presence of embedded auto-calibration provide the gauge with initially high metrological characteristics along with low cost of its manufacture.

The example 9.5 from JCGM-SI “Gauge block calibration” with a nominal length of 50 mm by the comparison method using a comparator and a reference measure of the same nominal length and the same material as the original standard is analyzed. In JCGM-SI compares the procedures for uncertainty evaluation, performed on the basis of the law of propagation of uncertainty (GUM) and the Monte Carlo method. The report uses the procedure developed by the authors, which consists Taylor-series expansion of the measurement model into a second-order series taking into account the kurtosis of input quantity distributions. To facilitate engineering calculations, the finite increment method is used. The excess method is used to find the expanded uncertainty. The good agreement of the results obtained by the proposed method with the results obtained by the Monte Carlo method is shown.

A system of measuring blind hole depth of the thermostat shell is designed by laser triangle method. The laser lines are extracted by using sub-pixel grayscale gradient arithmetic. And the standard gauge block is used to compensate the error caused by the measurement system. According to the shape and material of the shell, the CCD camera receives the shot picture by using the linear laser which is vertical to motion shell. By using the technology of three-dimensional reconstruction and point cloud splicing, the three-dimensional stereogram of the thermostat shell is got. And the thermostat shell is indirectly measured. The experiment shows that the system can effectively solve the problem of shell depth measurement. The arithmetic is simple. Compared with the traditional laser triangulation method, the accuracy has been improved by 6-8% by using compensation method based on standard gauge block. This system has a good reference and significance for other similar products.

A calibration pattern with linear light method for profile vision measurement is proposed. A plan for calibration pattern is made which of the pattern pins can fold back to pattern plate in accordance with rows separately. The unfolding pattern pins are photographed with linear light crossing that vertically one row at a time. The mathematical expression of transforming physical plane into pixel plane is derived by physical coordinates and pixel coordinates. With the least-square method the calibration coefficient is made. The method is validated through the means that magnetic gauge block used as a higher precision measurement standard is close to the profile. The experiment indicates that it is avoided that the pattern pins from different rows interrupt the linear light, and the profile measurement error is better than 0.2 mm.

Due to the complicated system constitution of three-dimensional measuring machine, it involves the multiple error components. So in the fast measurement, it is complicated to analyze spatial error characteristics in detail. In the experimental planning section, data are collected by measuring Gauge block in different length and different space positions. Then we use partial least square and kernel function to model and predict the experimental data. According to the result, the error of mean square in kernel function is 0.00542mm and the correlative coefficient is as high as 91.1373% while the mean square of partial least square is 0.3069mm. The experiment results indicate that the kernel function has a better imitative predictive effect than the partial least square and non-parametric modeling is more accurate than the parametric modeling in predicting spatial measurement error estimation of Coordinate Measuring Machine.

A Michelson interferometer method for determining the variation in length of gauge blocks is presented. This method is based on phase shift interferometer measuring a fringe fraction of the interference fringes on a gauge block measuring surface and its auxiliary plate. The reference standard of measurement is the wavelength of stabilized He-Ne Laser at 633 nm which is traceable to the international standard of the metre. The system was also verified by the 543 nm stabilized He-Ne Laser. The interference fringe patterns are observed by a CCD camera and the images are processed by a Machine Vision system. This make the system run automatically and fulfill. The measurement results were compared with the standard method and they agree with comparable uncertainty.

Displacement probes are currently widely used in different branches of manufacturing industry, either as building blocks of special purpose equipment or as a simple distance measuring instrument as for example in a gauge block calibrator. With the increased demand for more accurate products high resolution measuring probes gained more importance. Information about calibration procedures and equipments are rare in the literature. In the paper first the properties of the published calibration systems with nanometer resolution are discussed. Next the new calibration system having 50 nanometer measuring uncertainty is outlined The probe displacement is generated by a single-axis positioning stage driven by a stepping motor. The tip of the probe rests on the backface of the flat mirror with flatness better than λ/100, acting as the mirror of the plane mirror laser interferometer. Angular sensors are used to capture the angular deviation of the mirror in the different measuring positions. The error of the probe is the difference between the value determined by the probe and the value measured by the laser interferometer. Finally the calibration uncertainty is calculated and results are given to show the systems performance.

An accurate solution of a double step attenuation measurement technique with an internal gauge block for variable attenuators is presented. The solution is obtained by solving the signal flow graph of the circuit model with a small reflection coefficient (

In the Brinell Hardness Measure System based on vision, the measuring accuracy is greatly influenced by the huge interference, strong noises and non-smooth indentation edge in the indentation image amplified by object glass because of too many scratches on the surface and too small indentation of the metal block to be measured. In order to calibrate the practical pixel length, a standard gauge block and the Least Squares Method are adopted to fit the line of the block's edge. In the process of extracting the indentation diameter, the method based on region growing is utilized to segment the image and then, the circle detection method based on Existence Probability is applied to detect the indentation edge. The experiment testifies that these methods, which have better real-time performance and robustness, can better recover indentation edge and acquire indentation diameter.

The length difference between two gauge block were measured by using Michelson interferometer with stabilized He-Ne laser at 633 nm. The phase-shifting method was employed in order to create four interferograms. All interferograms were acquired by CCD camera and sent to computer. Length difference of any two gauge blocks was determined from phase difference at the central position of gauge blocks. The measurement uncertainty of 20 nm was achieved.

The influences of gauge block gestures for calibrating coordinate measuring machine(CMM) attach importance to people more and more. In particularly, gauge block gestures for metrology CMM can not be ignored to which the accuracy of linearity measurement is hyper to 0.6μm + 1000/L. Therefore, adjustable platform is developed and single-frequency laser interferometer is adopted as measuring datum to measure the influences of length variation of gauge blocks in different gestures. At the same time, advance multi-point bracing means to reduce the length variation of gauge blocks. The results of experiments indicate that multi-point bracing means make the maximum length variation of gauge blocks to be +0.07/μm. According to the uncertainty formula of indicating error to CMM, the standard uncertainty is recalculated as u″ c = +0.73μm.

One important step of phase-based 3D imaging system is calibration, which defines the relationship between phase and depth data. Existing calibration methods are complicated and hard to carry out because of using a translation stage or gauge block in a laboratory environment. This paper introduces an automatic calibration method by using a white and black checkerboard and a white plate having discrete markers with known separation and automatically determining each marker's position. The checkerboard determines the internal parameters of a CCD camera, while the plate gives depth and phase data to establish their relationship for each pixel. Experimental results and performance evaluation show that the proposed calibration method can reliably build up the accurate relationship between phase and depth data with an automatic way.

A test method for a 3D laser scanner based on the standard gauge block (SGB) is presented after the analysis of the factors influencing precision. The 16840 points of the SGB are measured in the secondary resolution. The precision of 3D laser scanner is tested by comparing the error between test data and the digital model of SGB using Geomagic Qualify software. 95.998% of the 3D measured points of the SGB fall into the tolerance range of 0.04mm. The 3D laser scanner satisfies the 2c quality requirements. The application shows that this method can be used to evaluate the precision of the 3D laser scanner and is appropriate for the test for similar scanners.

To realize precise micro-vision positioning based on edge detection of micro-structure parts, a pixel-level edge points detection method based on limit local entropy was proposed. 2-3 pixel were extended in the gradient direction to both sides from the edge points to construct the 3 cubic spline interpolation function of edge transition zone. Using function derivation to obtain the floating value of sub-pixel coordinates, then, sub-pixel coordinate was located according to the positioning principle of directional sub-pixel coordinates. Finally, the fine grinding standard gauge block and LIGA micro-spring were taken as example, using traditional gradient edge detection and the method proposed in this paper to realize image edge detection, and achieve the width measurement. The results show that the edge positioning accuracy of the method proposed in this paper is higher than the traditional gradient edge detection method. And whether the pixel level edge positioning accuracy or sub-pixel edge positioning accuracy are much higher than the positioning accuracy required of micro-assembly systems (5µm).

We describe in this paper a pilot experiment of a white-light fringe analysis with a low-cost color CCD camera. The used detection technique employs the phase-crossing algorithm which identifies the zero optical path difference as the point where the phase difference between the red, green and blue part of the white-light interference fringe becomes equal to zero. An experimental arrangement is based on superluminescent LED diode. The experimental setup is designed to be a crucial part of the complex system for automatic contactless diagnostic and calibration of gauge blocks.

A digital piezo system comprises a PZT and a capacitive sensor combined in a single unit. The desired displacement can be achieved by simply inputting the displacement value into the software. However, when target value of /spl lambda//8 was input to the three PZT's, the Fizeau plate did not show parallel movement, resulting in tilt to the linear fringes of the interferogram, In order to measure the length of the gauge block with high accuracy, this non-parallel movement of the Fizeau plate should be corrected precisely. This could be accomplished by multiplying correction factors to the target values of the piezo systems, which are self-measured by the phase shifting Fizeau interferometer.

A precise method, intended for nanometer accuracy in gauge block length measurements, has been realized. Results of the measurements are corrected on distortions in interferometer optics and are not affected by the quality of wringing and deformation of the reference plate. Accuracy limitations of the conventional method are outlined.

An interferometric comparator, featuring subnanometer reproducibility and resolution 10/sup -9/, is reported. A set of experiments is proposed for accurate measurements of corrections for interferometer optics and base plate flatness deviations, as well as for roughness of a block and a plate. A length decrease of 0.2 nm due to cleaning procedure of the block before wringing is detected.