Reverse projection photogrammetry has long been used to estimate the height of an individual in forensic video examinations. A natural extrapolation would be to apply the same technique on a video to ...estimate the speed of an object by determining the distance traveled between two points over a set amount of time. To test this theory, five digital video recorders (DVRs) were connected to a single fixed camera to record a vehicle traveling down a track. The vehicle's speed was measured through Doppler radar by a trained operator and the speedometer of the vehicle was also recorded with a video camera. The recorded video was examined and the frames that best depict the beginning and end of the vehicles course were selected. Two reverse projection photogrammetric examinations were performed on the selected frames to establish the position of the vehicle. The distance between the two points was measured, and the time elapsed between the two points was examined. The outcome provided an accurate speed result with a standard degree of uncertainty. This study proves the feasibility of using video data and reverse projection photogrammetry to determine the speed of a vehicle with a limited set of variables. Further research is needed to determine how additional variables would impact the standard degree of uncertainty.
Digital Photogrammetry Linder, Wilfried
2006, 2009, 2006-08-16, 2009-01-31, 20060401
eBook
"The second edition is an ""all-in-one"" combination of basic theory and practical exercises with software and data included on a CD-ROM. Potential readers/users are students of Photogrammetry, ...Geodesy, Geography and other sciences, but also all who are interested in this topic. No prior knowledge is necessary, except the handling of standard PCs. Theory is presented true to the motto ""as little as possible, but as much as necessary"". The main part of the book contains several tutorials. In increasing complexity, accompanied by texts explaining further theory, the reader can proceed step by step through the particular working parts. All intermediate as well as the final results are discussed with reference to accuracy and error handling, and included on the CD-ROM to provide controls. Most of the standard work in Digital Photogrammetry is shown and trained for example scanning, image orientation, mono and stereo plotting, aerial triangulation measurement (manual and automatic), block adjustment, automatic creation of surface models via image matching, creation of ortho images and mosaics, and others. Not only standard situations are dealt with but also more complex ones, such as unknown camera data, extreme relief or areas with very low contrast. Examples of both aerial and close-range photogrammetry present the power of these type of measurement techniques. The software is not limited to the example data included but may be used for personal projects. Part of the book comprises a complete description of the software. On the CD-ROM, versions in German, English and Spanish are available. Even 3-D images can be viewed with the accompanying 3-D glasses."
The purpose of this work is a comparative analysis of photogrammetry methods for three-dimensional scanning of buildings. This work contains a description of the photogrammetric techniques and their ...comparison. The paper identifies the features that arise during the three-dimensional reconstruction of buildings. In this work, also, a comparison of photogrammetric programs was made. The paper contains research on the influence of the identified features on the quality of the resulting model. Synthetic test data were created for research based on generating a sequence of images of an existing three-dimensional object. The benchmark was developed to automate calculating model quality metrics: Hausdorff distance, mean error, and root mean square error. The program accepts two models as input, calculates the given metrics, and builds a similarity color map.
The three-dimensional surface imaging system is becoming more common in plastic surgeries. However, few studies have assessed three-dimensional periocular structures and surgical outcomes. This study ...aimed to propose a standardized three-dimensional anthropometric protocol for the periocular region, investigate its precision and accuracy, and determine the three-dimensional periocular anthropometric norms for young Caucasians.
Thirty-nine healthy young Caucasians (78 eyes) were enrolled. Three-dimensional facial images were obtained with a VECTRA M3 stereophotogrammetry device. Thirty-eight measurements in periocular regions were obtained from these images. Every subject underwent facial surface capture twice to evaluate its precision. A paper ruler was applied to assess its accuracy.
Sixty-three percent of measurements in linear distances, curvatures, angles, and indices were found to reach a statistically significant difference between sexes (p ≤ 0.05, respectively). Across all measurements, the average mean absolute difference was 0.29 mm in linear dimensions, 0.56 mm in curvatures, 1.67 degrees in angles, and 0.02 in indices. In relative error of magnitude, 18 percent of the measurements were determined excellent, 51 percent very good, 31 percent good, and none moderate. The mean value of the paper-ruler scale was 10.01 ± 0.05 mm, the mean absolute difference value 0.02 mm, and the relative error of magnitude 0.17 percent.
This is the first study to propose a detailed and standardized three-dimensional anthropometric protocol for the periocular region and confirm its high precision and accuracy. The results provided novel metric data concerning young Caucasian periocular anthropometry and determined the variability between sexes.
Anthropometric features are important in determining gender and ethnic groups. The aim of this 3D photogrammetric study was to assess the face of Senegalese subjects.
A total of 104 3D facial ...photographs taken with the Bellus 3D application were studied. Measurements were taken at various anthropometric points using Meshlab software. The acquired data were recorded and processed using Jamovi software version 1.8.4.0. Correlations between the quantitative variables were tested and only one with a significance of p 0.05 was retained.
Overall, measured distances were higher in men. A statistically significant difference between men and women was found for nose width (p0. 001), face width (p < 0.005) and face height (p0. 0002). Conclusion: 3D anthropometric analysis shows a fairly significant sexual dimorphism, with males having greater facial and nasal proportions. A leptoprosopic (long) facial shape and a mesorrhine nose were maintained.
The field of photogrammetry has seen significant new developments essentially related to the emergence of new computer-based applications that have fostered the growth of the workflow technique ...called Structure-from-Motion (SfM). Low-cost, user-friendly SfM photogrammetry offers interesting new perspectives in coastal and other fields of geomorphology requiring high-resolution topographic data. The technique enables the construction of topographic products such as digital surface models (DSMs) and orthophotographs, and combines the advantages of the reproducibility of GPS surveys and the high density and accuracy of airborne LiDAR, but at very advantageous cost compared to the latter. Three SfM-based photogrammetric experiments were conducted on the embayed beach of Montjoly in Cayenne, French Guiana, between October 2013 and 2014, in order to map morphological changes and quantify sediment budgets. The beach is affected by a process of rotation induced by the alongshore migration of mud banks from the mouths of the Amazon River that generate spatial and temporal changes in wave refraction and incident wave angles, thus generating the reversals in longshore drift that characterise this process. Sub-vertical aerial photographs of the beach were acquired from a microlight aircraft that flew alongshore at low elevation (275m). The flight plan included several parallel flight axes with an overlap of 85% between pictures in the lengthwise direction and 50% between paths. Targets of 40×40cm, georeferenced by RTK-DGPS, were placed on the beach, spaced 100m apart. These targets served in optimizing the model and in producing georeferenced 3D products. RTK-GPS measurements of random points and cross-shore profiles were used to validate the photogrammetry results and assess their accuracy. We produced dense point clouds with 150 to 200points/m², from which we generated DSMs and orthophotos with respective resolutions of 10cm and 5cm. Compared to the GPS control points, we obtained a mean vertical accuracy less than ±10cm, with a maximum of 20cm in marginal sectors with sparse vegetation and in the lower intertidal zone where water-saturated surfaces generated lower-resolution data as a result of a lack of coherence between photographs. The overall results show that SfM photogrammetry is a robust tool for beach morphological and sediment budget surveys. Our SfM workflow enabled the discrimination of beach surface features at a scale of a few tens of centimetres despite the low textural contrasts exhibited by the quartz beach sand and the relatively uniform upper beach topography, as well as the calculation of beach sediment budgets. 66,000m³ of sand were removed from the northern sector of the beach, of which 22,000m³ were transferred to the southern sector in the course of rotation. Finally, we briefly highlight: (1) the advantages of SfM photogrammetry compared to other high-resolution survey methods, (2) the advantages and disadvantages of, respectively, a microlight aircraft and an unmanned aerial vehicle (UAV) in undertaking SfM photogrammetry, and (3) areas of potential future improvement of the SfM workflow technique. These concern more extensive cross-shore deployment of ground control points to reduce possible tilt, and oblique cross-shore photography to improve parallax.
•Low-cost photogrammetry enables high-resolution beach morphological monitoring.•Beach rotation in French Guiana was monitored by photogrammetry in 2013 and 2014.•We produced three digital surface models (DSMs) and sediment budgets for the beach.•We obtained a mean DSM accuracy <10cm on the upper dry beach.•The DSMs show beach morphological contrasts and rapid beach rotation over a year.
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