Mirror-based flexible one-step calibration method of light-sectioning system for surface topography

2018 ◽  
Vol 57 (20) ◽  
pp. 5583 ◽  
Author(s):  
Cong Liu ◽  
Xiaopeng Liu ◽  
Zhihong Xu ◽  
Xiaoyuan He ◽  
Xin Kang
Keyword(s):  
Surface Topography ◽  
Calibration Method ◽  
Light Sectioning ◽  
One Step

scholarly journals Influence of the calibration on experimental UV index at a midlatitude site, Granada (Spain)

2010 ◽  
Vol 3 (6) ◽  
pp. 5645-5670
Author(s):  
M. Antón ◽  
J. E. Gil ◽  
A. Cazorla ◽  
J. M. Vilaplana ◽  
F. J. Olmo ◽  
...  
Keyword(s):  
Calibration Method ◽  
Conversion Factors ◽  
Uv Index ◽  
Calibration Methods ◽  
One Step ◽  
The Difference ◽  
Mean Differences ◽  
Experimental Values ◽  
The One

Abstract. The ultraviolet (UV) index is the variable most commonly used to inform the general public about the levels and potential harmful effects of UV radiation incident at Earth's surface. This variable is derived from the output signal of the UV radiometers applying conversion factors obtained by calibration methods. This paper focused on the influence of the use of two of these methods (called one-step and two-steps methods) on the resulting experimental UV Index (UVI) as measured by a YES UVB-1 radiometer located in a midlatitude station, Granada (Spain) for the period 2006–2009. In addition, it is also analyzed the difference with the UVI values obtained when the calibration factors provided by the manufacturer are used. For this goal, the detailed characterization of the UVB-1 radiometer obtained in the first Spanish calibration campaign of broadband UV radiometers at the "El Arenosillo" INTA station in 2007 is used. In addition, modeled UVI data derived from the LibRadtran/UVSPEC radiative transfer code are compared with the experimental values recorded at Granada for cloud-free conditions. The absolute mean differences between the measured and modeled UVI data at Granada are around 5% using the one-step and two-steps calibration methods. This result indicates the excellent performance of these two techniques for obtaining UVI data from the UVB-1 radiometer. In contrast, the application of the calibration factor supplied by the manufacturer produces a high overestimation (~14%) of the UVI values. This fact generates unreliable alarming high UVI data in summer when the manufacturer's factor is used. Thus, days with an extreme erythemal risk (UVI higher than 10) increase up to 46% of all cases measured between May and September at Granada when the manufacturer's factor is applied. This percentage is reduced to a more reliable value of 3% when the conversion factors obtained with the two-steps calibration method are used. All these results report about the need of a sound calibration of the broadband UV instruments in order to obtain reliable measurements.

scholarly journals TWO-STEP CAMERA CALIBRATION METHOD DEVELOPED FOR MICRO UAV'S

2016 ◽  
Vol XLI-B1 ◽  
pp. 829-833 ◽  
Author(s):  
M. Gašparović ◽  
D. Gajski
Keyword(s):  
Camera Calibration ◽  
Calibration Method ◽  
Calibration Procedure ◽  
Unmanned Aircraft ◽  
Sensor Calibration ◽  
Step Process ◽  
Complex Process ◽  
One Step ◽  
Accurate Procedure ◽  
Wide Angle Camera

The development of unmanned aerial vehicles (UAVs) and continuous price reduction of unmanned systems attracted us to this research. Professional measuring systems are dozens of times more expensive and often heavier than "amateur", non-metric UAVs. For this reason, we tested the DJI Phantom 2 Vision Plus UAV. Phantom’s smaller mass and velocity can develop less kinetic energy in relation to the professional measurement platforms, which makes it potentially less dangerous for use in populated areas. In this research, we wanted to investigate the ability of such non-metric UAV and find the procedures under which this kind of UAV may be used for the photogrammetric survey. It is important to emphasize that UAV is equipped with an ultra wide-angle camera with 14MP sensor. Calibration of such cameras is a complex process. In the research, a new two-step process is presented and developed, and the results are compared with standard one-step camera calibration procedure. Two-step process involves initially removed distortion on all images, and then uses these images in the phototriangulation with self-calibration. The paper presents statistical indicators which proved that the proposed two-step process is better and more accurate procedure for calibrating those types of cameras than standard one-step calibration. Also, we suggest two-step calibration process as the standard for ultra-wideangle cameras for unmanned aircraft.

scholarly journals Non-orthogonal one-step calibration method for robotized transcranial magnetic stimulation

2018 ◽  
Vol 17 (1) ◽  
Author(s):  
He Wang ◽  
Jingna Jin ◽  
Xin Wang ◽  
Ying Li ◽  
Zhipeng Liu ◽  
...  
Keyword(s):  
Transcranial Magnetic Stimulation ◽  
Magnetic Stimulation ◽  
Calibration Method ◽  
One Step

One step geometrical calibration method for optical coherence tomography

2015 ◽  
Vol 18 (1) ◽  
pp. 015301 ◽  
Author(s):  
Jesús Díaz Díaz ◽  
Jenny Stritzel ◽  
Maik Rahlves ◽  
Omid Majdani ◽  
Eduard Reithmeier ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Calibration Method ◽  
Optical Coherence ◽  
One Step

scholarly journals TWO-STEP CAMERA CALIBRATION METHOD DEVELOPED FOR MICRO UAV'S

2016 ◽  
Vol XLI-B1 ◽  
pp. 829-833 ◽  
Author(s):  
M. Gašparović ◽  
D. Gajski
Keyword(s):  
Camera Calibration ◽  
Calibration Method ◽  
Calibration Procedure ◽  
Unmanned Aircraft ◽  
Sensor Calibration ◽  
Step Process ◽  
Complex Process ◽  
One Step ◽  
Accurate Procedure ◽  
Wide Angle Camera

The development of unmanned aerial vehicles (UAVs) and continuous price reduction of unmanned systems attracted us to this research. Professional measuring systems are dozens of times more expensive and often heavier than "amateur", non-metric UAVs. For this reason, we tested the DJI Phantom 2 Vision Plus UAV. Phantom’s smaller mass and velocity can develop less kinetic energy in relation to the professional measurement platforms, which makes it potentially less dangerous for use in populated areas. In this research, we wanted to investigate the ability of such non-metric UAV and find the procedures under which this kind of UAV may be used for the photogrammetric survey. It is important to emphasize that UAV is equipped with an ultra wide-angle camera with 14MP sensor. Calibration of such cameras is a complex process. In the research, a new two-step process is presented and developed, and the results are compared with standard one-step camera calibration procedure. Two-step process involves initially removed distortion on all images, and then uses these images in the phototriangulation with self-calibration. The paper presents statistical indicators which proved that the proposed two-step process is better and more accurate procedure for calibrating those types of cameras than standard one-step calibration. Also, we suggest two-step calibration process as the standard for ultra-wideangle cameras for unmanned aircraft.

Calibration Method and Experimental Study of the Camera Internal Parameters Based on One-Step Movement

2011 ◽  
Vol 464 ◽  
pp. 70-75
Author(s):  
Xing Long Zhu ◽  
Jun Jun Zhu ◽  
Ying Zhang ◽  
Jj Ping Zhou ◽  
Long Qin Gao ◽  
...  
Keyword(s):  
Experimental Study ◽  
Calibration Method ◽  
The Other ◽  
Step Movement ◽  
Internal Calibration ◽  
Internal Parameters ◽  
One Step ◽  
Ccd Image ◽  
Geometrical Relationship ◽  
Calibration Parameters

A calibration method based on target features circle is proposed, which can determine the camera internal parameters based on the two different CCD images. One CCD image can be obtained in a position, and the other CCD image can be gotten by moving the target or camera to a new position. The principle of the calibration method based on one-step movement is expounded. The geometrical relationship and the criteria that the camera axis is orthogonal to the target plane are proven when the CCD image is circle. Finally, the experiment results verify that the method proposed is effective, and the data of the internal calibration parameters of the camera is given.

Three-dimensional measuring technique for surface topography using a light-sectioning microscope

2012 ◽  
Vol 51 (8) ◽  
pp. 1162 ◽  
Author(s):  
Linglin Xia ◽  
Peifeng Chen ◽  
Ying Wang ◽  
Le Zhou ◽  
Xi Luo
Keyword(s):  
Surface Topography ◽  
Three Dimensional ◽  
Measuring Technique ◽  
Light Sectioning

scholarly journals Influence of the calibration on experimental UV index at a midlatitude site, Granada (Spain)

2011 ◽  
Vol 4 (3) ◽  
pp. 499-507 ◽  
Author(s):  
M. Antón ◽  
J. E. Gil ◽  
A. Cazorla ◽  
J. Fernández-Gálvez ◽  
J. M. Vilaplana ◽  
...  
Keyword(s):  
Harmful Effect ◽  
Calibration Method ◽  
Conversion Factors ◽  
Uv Index ◽  
Calibration Methods ◽  
One Step ◽  
Mean Differences ◽  
Experimental Values ◽  
The One

Abstract. The ultraviolet index (UVI) is the most commonly used variable to inform about the level and potential harmful effect of ultraviolet (UV) radiation reaching the Earth's surface. This variable is derived from the output signal of UV radiometers applying conversion factors from calibration methods. This paper focused on the influence of the use of two of these methods (called one-step and two-steps methods) on the experimental UVI measured by a YES UVB-1 radiometer located in a midlatitude station, Granada (Spain) for the period 2006–2009. In addition, it also analyzes the deviation from the UVI values obtained when the manufacturer's calibration factors are applied. For this goal, a detailed characterization of the UVB-1 radiometer from the first Spanish calibration campaign of broadband UV radiometers at the "El Arenosillo" INTA station in 2007 was used. In addition, modeled UVI data derived from the LibRadtran/UVSPEC radiative transfer code are compared with the experimental values recorded at Granada for cloud-free conditions. Absolute mean differences between measured and modeled UVI data at Granada were around 5% using the one-step and two-steps calibration methods, indicating an excellent performance of these two techniques for obtaining UVI data from the UVB-1 radiometer. Conversely, the application of the manufacture's calibration factor produced a large overestimation (~14%) of the UVI values, generating unreliable alarming high UVI data in summer. Thus, the number of days with an extreme erythemal risk (UVI higher than 10) increased up to 46% between May and September at Granada. This percentage reduced to a more reliable value of 3% when the conversion factors obtained with the two-steps calibration method are used. These results evidence the need for a sound calibration of the broadband UV instruments in order to obtain reliable measurements.

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