Test Charts for Evaluating Imaging and Point Cloud Quality of Mobile Mapping Systems for Urban Street Space Acquisition

Pfeifer, Norbert; Falkner, Johannes; Bayr, Andreas; Eysn, Lothar; Ressl, Camillo

doi:10.3390/rs13020237

Cited by 4 publications

(2 citation statements)

References 25 publications

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“…To avoid bias in this assessment, a panel of 3 objective assessors was then asked to inspect, discuss, and come to a consensus on a score of completeness for each of the 36 cross sections. The mean score for each flight strategy was then used to compare the completeness of the models that had been generated (Pfeifer et al 2021). The score for completeness for each cross section was based on the following scale: The software was able to incorporate all the images taken by the UAV into all 3D photogrammetric models of the branches.…”

Section: Accuracy Trialmentioning

confidence: 99%

Miniature UAVs and Photogrammetry—A Novel Approach to Collecting Aerial Inspection Data from Mature Broadleaf Trees

Roberts

Slater²

2023

AUF

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Background: Production of high-quality 3D models of trees has a practical application in arboriculture, allowing the assessment, measurement, and recording of aboveground structural features of individual trees. Commercially available hobby UAVs (uncrewed aerial vehicles) with integrated cameras in combination with a low-cost photogrammetry software package can produce high-definition 3D models of tree structures with low financial investment. Methods: Our study compared an established orbital flight strategy and 2 novel close-range flight strategies for collecting digital imagery to produce 3D models of features of interest (FOIs) in trees. We used 3 separate tests to establish if these different flight strategies resulted in reliable, measurable, and complete models for FOIs in mature broadleaf trees. Results: Our study substantiated the findings of previous studies, in that a well-planned, automated orbital strategy of flight can render full models of trees from which accurate measurement of dimensions can be obtained. A flight strategy involving collecting clusters of images from different angles whilst the UAV stayed in one location was trialled, and the resulting models were typically incomplete and of low quality. However, the second close-range strategy of hand-flown missions running parallel with the FOI yielded highly detailed, complete models from which observations of the FOI’s surface and accurate measurements of its dimensions could be obtained. Conclusions: We conclude that there are substantial opportunities for the use of low-cost UAVs to undertake visual tree assessments of the aerial parts of trees, subject to ease of access to the feature and the right choice of flight strategy.

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Section: Accuracy Trialmentioning

confidence: 99%

Miniature UAVs and Photogrammetry—A Novel Approach to Collecting Aerial Inspection Data from Mature Broadleaf Trees

Roberts

Slater²

2023

AUF

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“…If the point density is, e.g., twice as high in scan line direction, a factor of 2 will yield. In (Pfeifer et al, 2021), this measure is applied to data which is expected to lie in a plane, whereas the data studied here is distributed in 3D. In case of (nearly) vertical surfaces an adapted selection strategy is required.…”

Section: Datasetsmentioning

confidence: 99%

A Framework for Generic Spatial Search in 3d Point Clouds

Otepka

Mandlburger

Karel

et al. 2021

ISPRS Ann. Photogramm. Remote Sens. Spatial Inf. Sci.

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Abstract. Modern data acquisition with active or passive photogrammetric imaging techniques generally results in 3D point clouds. Depending on the acquisition or processing method, the spacing of the individual points is either uniform or irregular. In the latter case, the neighbourhood definition like for digital images (4- or 8-neighbourhood, etc.) cannot be applied. Instead, analysis requires a local point neighbourhood. The local point neighbourhood with conventional k-nearest neighbour or fixed distance searches often produce sub-optimal results suffering from the inhomogeneous point distribution. In this article, we generalize the neighbourhood definition and present a generic spatial search framework which explicitly deals with arbitrary point patterns and aims at optimizing local point selection for specific processing tasks like interpolation, surface normal estimation and point feature extraction, spatial segmentation, and such like. The framework provides atomic 2D and 3D search strategies, (i) k-nearest neighbour, (ii) region query, (iii) cell based selection, and (iv) quadrant/octant based selection. It allows to freely combine the individual strategies to form complex, conditional search queries as well as specifically tailored point sub-selection. The benefits of such a comprehensive neighbourhood search approach are showcased for feature extraction and surface interpolation of irregularly distributed points.

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Multi feature-rich synthetic colour to improve human visual perception of point clouds

Balado¹,

González²,

Rodríguez-Somoza³

et al. 2023

ISPRS Journal of Photogrammetry and Remote Sensing

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Test Charts for Evaluating Imaging and Point Cloud Quality of Mobile Mapping Systems for Urban Street Space Acquisition

Cited by 4 publications

References 25 publications

Miniature UAVs and Photogrammetry—A Novel Approach to Collecting Aerial Inspection Data from Mature Broadleaf Trees

Miniature UAVs and Photogrammetry—A Novel Approach to Collecting Aerial Inspection Data from Mature Broadleaf Trees

A Framework for Generic Spatial Search in 3d Point Clouds

Multi feature-rich synthetic colour to improve human visual perception of point clouds

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