Evaluation of Test Field-based Calibration and Self-calibration Models of UAV Integrated Compact Cameras

Kazar, Gülüstan Kılınç; Karabörk, Hakan; Makineci, Hasan Bilgehan

doi:10.1007/s12524-021-01454-y

Cited by 8 publications

(8 citation statements)

References 9 publications

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“…To reveal the influence of the camera calibration parameters on photogrammetric products such as point cloud and DEM, images obtained from Flights 2, 6 in Table 2 and free flight were combined together and evaluated using Agisoft MetaShape software (Kılınç-Kazar et al, 2022;Sağdıç et al, 2022). Using the images of these flight, camera calibration parameters, the focal length (f) and the calibrated focal length (c) were calculated and these values were fixed during the re-evaluation of the 1st flight and comparisons were made on the generated point cloud and DEM.…”

Section: Resultsmentioning

confidence: 99%

Investigation of the effects of different flight parameters on the accuracy of DEM generated using UAV systems

Bulut

YILMAZTÜRK

2022

Turkish Journal of Geosciences

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UAV Orthomosaic DEM Rolling ShutterUnmanned Aerial Vehicles (UAVs), can be controlled automatically or with the help of a remote control system, provide high spatial and temporal resolution images in addition to its advantages in terms of cost and time. Due to these features, UAV's have been widely used in studies such as map production, 3D modeling and volume calculation in recent years. In this study, it is aimed to investigate the effects of different flight parameters on the accuracy of Orthomosaic and DEM produced with UAV Systems. In addition, the rolling shutter effect and the use of pre-calibrated and automatic camera calibration parameters were also tested. For this purpose, a total of seven UAV flights were carried out at different heights, overlap ratios, angles and grids at a mining area located within the borders of Aksaray province. Agisoft MetaShape and Pix4D Mapper, which are widely used commercial software, were used to process the UAV images. In this study, 27 points were established and 3D coordinates of these points were measured using GNSS technique. 15 of these points were used as reference points and the remaining 12 points were used as check points. Accuracy analysis was performed by comparing the produced Orthomosaics and DEMs with the check points in the study area. CloudCompare and ArcGIS software were used in the comparison of the products as a result of the evaluation of the images. It is concluded that the Orthomosaics produced using 45 0 angle and DEMs with 60 0 angle has higher accuracy than the others. Point clouds and DEMs' produced using automatic and pre-calibrated camera calibration parameters show that the precalibrated images provide higher accuracy. Also, it is seen that when the rolling shutter effect is modeled, the horizontal and vertical accuracy is increased in all three flights with different flight parameters in this study.

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Section: Resultsmentioning

confidence: 99%

Investigation of the effects of different flight parameters on the accuracy of DEM generated using UAV systems

Bulut

YILMAZTÜRK

2022

Turkish Journal of Geosciences

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“…The IO parameters of the camera used in every operation with non-metric cameras should be obtained because the results obtained after the application are expected to be of a standard acceptable to everyone and high accuracy in photogrammetry. Furthermore, camera calibration is a fundamental process since it is necessary to eliminate the effects of geometric and radiometric deformations arising from the characteristics of optical imaging systems and the IO parameters of the device to be used in researches where high accuracy and precision are required (Kılınç Kazar, et al, 2021). Thus, different mathematical models and methods for the calibration process must be done before every operation where high accuracy and precision are required.…”

Section: Discussionmentioning

confidence: 99%

“…Non-metric cameras, used instead of metric cameras due to high cost, must be calibrated by users. In the calibration report, the values that should be found are the Interior Orientation (IO) parameters (X h , Y h , f) and the polynomial coefficients of the function expressing the lens distortion (K 1 , K 2 , K 3 , and P 1 , P 2 ) (Kılınç Kazar, et al, 2021;Khalaf and Yassin, 2016;Zhang et. Al., 2010).…”

Section: Introductionmentioning

confidence: 99%

Defining The Relationship Between The Diameters of The Points Used in 2D Test Platforms and The Parameters Obtained from Camera Calibration

SAĞDIÇ

Makineci

Karabörk

2022

International Journal of Environment and Geoinformatics

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With the developing technology in recent years, there has been a significant increase in 3D spatial data needs and data production. 3D spatial data occupy an important place in almost every field. As a result, there is a need for 3D spatial data production and the produced data's reliability. Like all spatial measuring equipment, cameras, which are data production units used in photogrammetry, must also be calibrated to produce reliable data. Calibration for non-metric cameras is critical to ensure that the measurements are highly accurate and at standards acceptable to everyone. In this study, to determine the factors affecting the calibration, terrestrial photogrammetric images were taken with a Canon EOS 600D non-metric camera with different point diameters on the calibration paper. These images were evaluated in the camera calibration software, and the photogrammetric result accuracies were investigated. The effects of the point diameters on the camera calibration paper on the calibration results have been observed. A4, A3, A0 sizes were printed and calibrated for both calibration papers. As a result of the printouts, as can be predicted, the largest point sizes are A0, which has the largest paper size, and according to the results, it was seen that the highest accuracy was achieved in the A0 dimension. The Relationship between the accuracy obtained in the calibration process and the point diameters in the test area was examined in this study. When the 144-point test area presented by the software is printed in A0 size, the point diameters were measured 1.00 cm. In this study, calibration processes were performed as 1.00 cm, 1.20 cm, 1.40 cm, 1.60 cm, 1.80 cm, and 2.00 cm by enlarging the point diameters by 20%, and more accurate results were obtained more quickly than other paper sizes and calibration methods. As a result, since the calibration of the device to be used in the studies directly affects the model's accuracy to be obtained at the end of the study, it is necessary to take the maximum accuracy obtained in the calibration process. In this research, the calibration process's highest accuracy is aimed at and how the calibration process can be performed more effortlessly and more accurately by increasing the size of the point diameter on the test area.

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“…A comparison of self-calibration and pre-calibration was also performed in [67]. The researchers evaluated a test field-based calibration for DJI Phantom 4 Pro and Parrot Anafi UAVs.…”

Section: Camera Calibrationmentioning

confidence: 99%

Optimising UAV Data Acquisition and Processing for Photogrammetry: A Review

Pargieła

2023

GaEE

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Unmanned aerial vehicles (UAVs) are used to acquire measurement data for an increasing number of applications. Photogrammetric studies based on UAV data, thanks to the significant development of computer vision techniques, photogrammetry, and equipment miniaturization, allow sufficient accuracy for many engineering and non-engineering applications to be achieved. In addition to accuracy, development time and cost of data acquisition and processing are also important issues. The aim of this paper is to present potential limitations in the use of UAVs to acquire measurement data and to present measurement and processing techniques affecting the optimisation of work both in terms of accuracy and economy. Issues related to the type of drones used (multi-rotor, fixed-wing), type of shutter in the camera (rolling shutter, global shutter ), camera calibration method (pre-calibration, self-calibration), georeferencing method (direct, indirect), technique of measuring the external images orientation parameters (RTK, PPK, PPP), flight design methods and the type of software used were analysed.

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Evaluation of Test Field-based Calibration and Self-calibration Models of UAV Integrated Compact Cameras

Cited by 8 publications

References 9 publications

Investigation of the effects of different flight parameters on the accuracy of DEM generated using UAV systems

Investigation of the effects of different flight parameters on the accuracy of DEM generated using UAV systems

Defining The Relationship Between The Diameters of The Points Used in 2D Test Platforms and The Parameters Obtained from Camera Calibration

Optimising UAV Data Acquisition and Processing for Photogrammetry: A Review

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