scholarly journals DistoX calibration tools and the need for calibration checking

2021 ◽  
Vol 50 (1) ◽  
Author(s):  
Matija Perne
Keyword(s):  
Measurement Error ◽  
Theoretical Consideration ◽  
Calibration Method ◽  
Calibration Error ◽  
Adequate Accuracy

For proper cave surveying using DistoX, the device needs to be calibrated with adequate accuracy. Calibrating does not require any tools; but, tools to make calibration easier have been developed. Theoretical consideration shows that the use of certain tools enables one to introduce a type of calibration error that goes undetected by the calibration software. In this study, the existence of such errors is experimentally confirmed and their magnitude is estimated. It is demonstrated to be crucial that the DistoX is calibrated and that the calibration is valid, that is, that the device has not changed since it was last calibrated. No part of the DistoX must have moved or changed its magnetization since calibration, not even the battery. The calibration method used and the quality of the resulting calibration are important too. It is highly recommended that the DistoX be checked immediately before surveying a cave and thus avoid the possibility of using an uncalibrated, not validly calibrated, or poorly calibrated device. To complete the check, a few survey shots are measured multiple times with the device at different roll angles, and the back shot of one of the shots is measured. If the device is properly calibrated, the measurements will agree with each other within the acceptable measurement error. This is not the case for a device that is not properly calibrated.

scholarly journals A Machine Vision Rapid Method to Determine the Ripeness Degree of Olive Lots

Sensors ◽  
2021 ◽  
Vol 21 (9) ◽  
pp. 2940
Author(s):  
Luciano Ortenzi ◽  
Simone Figorilli ◽  
Corrado Costa ◽  
Federico Pallottino ◽  
Simona Violino ◽  
...  
Keyword(s):  
Machine Vision ◽  
Nearest Neighbors ◽  
Calibration Method ◽  
Mobile App ◽  
Harvest Time ◽  
Automatic Assessment ◽  
K Nearest Neighbors ◽  
Olive Ripeness ◽  
Olive Ripening

The degree of olive maturation is a very important factor to consider at harvest time, as it influences the organoleptic quality of the final product, for both oil and table use. The Jaén index, evaluated by measuring the average coloring of olive fruits (peel and pulp), is currently considered to be one of the most indicative methods to determine the olive ripening stage, but it is a slow assay and its results are not objective. The aim of this work is to identify the ripeness degree of olive lots through a real-time, repeatable, and objective machine vision method, which uses RGB image analysis based on a k-nearest neighbors classification algorithm. To overcome different lighting scenarios, pictures were subjected to an automatic colorimetric calibration method—an advanced 3D algorithm using known values. To check the performance of the automatic machine vision method, a comparison was made with two visual operator image evaluations. For 10 images, the number of black, green, and purple olives was also visually evaluated by these two operators. The accuracy of the method was 60%. The system could be easily implemented in a specific mobile app developed for the automatic assessment of olive ripeness directly in the field, for advanced georeferenced data analysis.

Normalization of the permissible error in measuring the mass when controlling the parts of the connecting rod-piston group

2021 ◽  
pp. 40-44
Author(s):  
Keyword(s):  
Measurement Error ◽  
Mass Difference ◽  
Measuring Instruments ◽  
Connecting Rod ◽  
Mass Measurements ◽  
Indirect Measurements ◽  
Piston Group ◽  
Complete Set ◽  
The Difference

The problems related to the standardization of the error in the mass measurements when dividing products into groups and picking according to the difference in mass are considered. On the basis of the theory of probabilities and the basic provisions of metrology, a dependence is obtained to determine the error of the mass difference. Recommendations are given for improving the metrological support of indirect measurements of the mass difference, a formula is determined for calculating the normalized values of errors depending on the tolerances for the mass difference, and criteria for choosing measuring instruments for controlling the mass difference of parts at the stage of completing the connecting rod-piston group during the production and repair of engines are considered. The measurement error is estimated when using preassembly selection of parts by weight. Keywords: quality of measurements, mass measurements, mass difference, indirect measurements, choice of measuring instruments, permissible measurement error, complete set of connecting rod and piston group. [email protected]

scholarly journals Simulation of the Operation of a Single Pixel Camera with Compressive Sensing in the Long-Wave Infrared

2021 ◽  
Vol 25 (2) ◽  
pp. 53-60
Author(s):  
Anna Szajewska
Keyword(s):  
Case Analysis ◽  
Calibration Method ◽  
Reconstruction Error ◽  
Infrared Observation ◽  
Long Wave ◽  
Reference Images ◽  
The Impact ◽  
Long Wave Infrared ◽  
Single Pixel

Imaging with the use of a single pixel camera and based on compressed sensing (CS) is a new and promising technology. The use of CS allows reconstruction of images in various spectrum ranges depending on the spectrum sensibility of the used detector. During the study image reconstruction was performed in the LWIR range based on a thermogram from a simulated single pixel camera. For needs of reconstruction CS was used. A case analysis showed that the CS method may be used for construction of infrared-based observation single pixel cameras. This solution may also be applied in measuring cameras. Yet the execution of a measurement of radiation temperature requires calibration of results obtained by CS reconstruction. In the study a calibration method of the infrared observation camera was proposed and studies were carried out of the impact exerted by the number of measurements made on the quality of reconstruction. Reconstructed thermograms were compared with reference images of infrared radiation. It has been ascertained that the reduction of the reconstruction error is not directly in proportion to the number of collected samples being collected. Based on a review of individual cases it has been ascertained that apart from the number of collected samples, an important factor that affects the reconstruction fidelity is the structure of the image as such. It has been proven that estimation of the error for reconstructed thermograms may not be based solely on the quantity of executed measurements.

scholarly journals HYBRID ONLINE MOBILE LASER SCANNER CALIBRATION THROUGH IMAGE ALIGNMENT BY MUTUAL INFORMATION

2016 ◽  
Vol III-1 ◽  
pp. 25-31 ◽  
Author(s):  
Mourad Miled ◽  
Bahman Soheilian ◽  
Emmanuel Habets ◽  
Bruno Vallet
Keyword(s):  
Mutual Information ◽  
Imaging System ◽  
Laser Scanner ◽  
Point Clouds ◽  
Calibration Method ◽  
Online Calibration ◽  
Calibration Methods ◽  
Laser Calibration ◽  
Scanner Calibration

This paper proposes an hybrid online calibration method for a laser scanner mounted on a mobile platform also equipped with an imaging system. The method relies on finding the calibration parameters that best align the acquired points cloud to the images. The quality of this intermodal alignment is measured by Mutual information between image luminance and points reflectance. The main advantage and motivation is ensuring pixel accurate alignment of images and point clouds acquired simultaneously, but it is also much more flexible than traditional laser calibration methods.

scholarly journals A Nonlinear Calibration Method Based on Sinusoidal Excitation and DFT Transformation for High-Precision Power Analyzers

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Wenjian Zhou ◽  
Sheng Yang ◽  
Li Wang ◽  
Hanmin Sheng ◽  
Yang Deng
Keyword(s):  
High Precision ◽  
Interpolation Method ◽  
Spline Interpolation ◽  
Calibration Method ◽  
Calibration Error ◽  
Initial Moment ◽  
Calibration Process ◽  
Calibration Methods ◽  
Nonlinear Calibration ◽  
Sinusoidal Excitation

For most high-precision power analyzers, the measurement accuracy may be affected due to the nonlinear relationship between the input and output signal. Therefore, calibration before measurement is important to ensure accuracy. However, the traditional calibration methods usually have complicated structures, cumbersome calibration process, and difficult selection of calibration points, which is not suitable for situations with many measurement points. To solve these issues, a nonlinear calibration method based on sinusoidal excitation and DFT transformation is proposed in this paper. By obtaining the effective value data of the current sinusoidal excitation from the calibration source, the accurate calibration process can be done, and the calibration efficiency can be improved effectively. Firstly, through Fourier transform, the phase value at the initial moment of the fundamental frequency is calculated. Then, the mapping relationship between the sampling value and the theoretical calculation value is established according to the obtained theoretical discrete expression, and a cubic spline interpolation method is used to further reduce the calibration error. Simulations and experiments show that the calibration method presented in this paper achieves high calibration accuracy, and the results are compensation value after calibration with a deviation of ± 3 × 10 − 4 .

scholarly journals Global Calibration of Multi-Cameras Based on Refractive Projection and Ray Tracing

2017 ◽  
Author(s):  
Mingchi Feng ◽  
Xiang Jia ◽  
Jingshu Wang ◽  
Song Feng ◽  
Taixiong Zheng
Keyword(s):  
Ray Tracing ◽  
Real Data ◽  
Calibration Method ◽  
Calibration Error ◽  
Multiple Cameras ◽  
Projection Model ◽  
Vision Measurement ◽  
3D Computer Vision ◽  
Global Calibration ◽  
Calibration Methods

Multi-cameras system is widely applied in 3D computer vision especially when multiple cameras are distributed on both sides of the measured object. The calibration methods of multi-cameras system are critical to the accuracy of vision measurement and the key is to find an appropriate calibration target. In this paper, a high-precision camera calibration method for multi-cameras system based on transparent glass checkerboard and ray tracing is described, which is used to calibrate multiple cameras distributed on both sides of the glass checkerboard. Firstly, the intrinsic parameters of each camera is obtained by Zhang’s calibration method. Then, multiple cameras capture several images from the front and back of the glass checkerboard with different orientations, and all images contain distinct grid corners. As the cameras on one side are not affected by the refraction of glass checkerboard, extrinsic parameters can be directly calculated. However, the cameras on another side are influenced by the refraction of glass checkerboard, and the direct use of projection model will produce calibration error. A multi-cameras calibration method using refractive projection model and ray tracing is developed to eliminate this error. Furthermore, both synthetic and real data are employed to validate the proposed approach. The experimental results of refractive calibration show that the error of the 3D reconstruction is smaller than 0.2 mm, the relative errors of both rotation and translation are less than 0.014%, and the mean and standard deviation of reprojection error of 4-cameras system are 0.00007 and 0.4543 pixel. The proposed method is flexible, high accurate, and simple to carry out.

scholarly journals Non-invasive aberration correction and adaptive ultrasound imaging with a time reversal virtual array

2021 ◽  
Vol 88 (s1) ◽  
pp. s34-s36
Author(s):  
Lars Grüter ◽  
Richard Nauber ◽  
Jürgen Czarske
Keyword(s):  
Time Reversal ◽  
Model Experiment ◽  
Calibration Method ◽  
Wavefront Correction ◽  
Non Invasive ◽  
Numerical Characterization ◽  
Virtual Array ◽  
Multi Mode ◽  
Method Show

Abstract Strong acoustical aberrations such as induced by multi-mode waveguides or the human skull can significantly reduce the quality of or prevent effective ultrasoundbased imaging. We propose a novel non-invasive calibration method that utilizes two independent acoustical accesses and a time reversal virtual array (TRVA) for adaptive wavefront correction. Numerical characterization and a model experiment utilizing this method show an improvement of the lateral resolution and the peak to background ratio by up to 35% and 10% respectively.

Study of Split Capacitor DAC Mismatch and Calibration in SAR-ADC

2016 ◽  
Vol 26 (01) ◽  
pp. 1750003
Author(s):  
Yun Zhang ◽  
Yiqiang Zhao ◽  
Peng Dai
Keyword(s):  
Calibration Method ◽  
Sar Adc ◽  
Calibration Error ◽  
Cmos Process ◽  
Analog To Digital ◽  
Significant Performance ◽  
Performance Deterioration ◽  
Conventional Structure ◽  
Split Capacitor ◽  
Simulation Results

Mismatch and parasitic effects of bridge capacitors in successive-approximation-register analog-to-digital converter’s (SAR-ADC) split capacitor digital-to-analog conversion (DAC) cause a significant performance deterioration. This paper presents a nonlinearity analysis based on an analytical model, and a modified calibration method utilizing a pre-bias bridge capacitor is accordingly proposed. The proposed method, which uses three-segment split capacitor DAC structure, can effectively eliminate over-calibration error caused by conventional structure. To verify the technique, a 14-bit SAR-ADC has been designed in 0.35-[Formula: see text]m 2P4M CMOS process with the PIP capacitor, and the simulation results show the method can further improve ADC performance.

scholarly journals COSMIN Risk of Bias tool to assess the quality of studies on reliability or measurement error of outcome measurement instruments: a Delphi study

2020 ◽  
Vol 20 (1) ◽  
Author(s):  
L. B. Mokkink ◽  
M. Boers ◽  
C. P. M. van der Vleuten ◽  
L. M. Bouter ◽  
J. Alonso ◽  
...  
Keyword(s):  
Measurement Error ◽  
Delphi Study ◽  
Outcome Measurement ◽  
Research Question ◽  
Measurement Instrument ◽  
Measurement Properties ◽  
Measurement Instruments ◽  
Sources Of Variation ◽  
The Impact

Abstract Background Scores on an outcome measurement instrument depend on the type and settings of the instrument used, how instructions are given to patients, how professionals administer and score the instrument, etc. The impact of all these sources of variation on scores can be assessed in studies on reliability and measurement error, if properly designed and analyzed. The aim of this study was to develop standards to assess the quality of studies on reliability and measurement error of clinician-reported outcome measurement instruments, performance-based outcome measurement instrument, and laboratory values. Methods We conducted a 3-round Delphi study involving 52 panelists. Results Consensus was reached on how a comprehensive research question can be deduced from the design of a reliability study to determine how the results of a study inform us about the quality of the outcome measurement instrument at issue. Consensus was reached on components of outcome measurement instruments, i.e. the potential sources of variation. Next, we reached consensus on standards on design requirements (n = 5), standards on preferred statistical methods for reliability (n = 3) and measurement error (n = 2), and their ratings on a four-point scale. There was one term for a component and one rating of one standard on which no consensus was reached, and therefore required a decision by the steering committee. Conclusion We developed a tool that enables researchers with and without thorough knowledge on measurement properties to assess the quality of a study on reliability and measurement error of outcome measurement instruments.

scholarly journals Combining biomarker and self-reported dietary intake data: A review of the state of the art and an exposition of concepts

2019 ◽  
Vol 29 (2) ◽  
pp. 617-635 ◽  
Author(s):  
Isobel Claire Gormley ◽  
Yuxin Bai ◽  
Lorraine Brennan
Keyword(s):  
Measurement Error ◽  
Dietary Intake ◽  
Measurement Errors ◽  
State Of The Art ◽  
Calibration Method ◽  
Simulation Studies ◽  
Dietary Biomarkers ◽  
Dietary Intake Assessment ◽  
Reported Data ◽  
Further Development

Classical approaches to assessing dietary intake are associated with measurement error. In an effort to address inherent measurement error in dietary self-reported data there is increased interest in the use of dietary biomarkers as objective measures of intake. Furthermore, there is a growing consensus of the need to combine dietary biomarker data with self-reported data. A review of state of the art techniques employed when combining biomarker and self-reported data is conducted. Two predominant methods, the calibration method and the method of triads, emerge as relevant techniques used when combining biomarker and self-reported data to account for measurement errors in dietary intake assessment. Both methods crucially assume measurement error independence. To expose and understand the performance of these methods in a range of realistic settings, their underpinning statistical concepts are unified and delineated, and thorough simulation studies are conducted. Results show that violation of the methods' assumptions negatively impacts resulting inference but that this impact is mitigated when the variation of the biomarker around the true intake is small. Thus there is much scope for the further development of biomarkers and models in tandem to achieve the ultimate goal of accurately assessing dietary intake.

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