Search results for "Close range photogrammetry"
showing 4 items of 14 documents
A NEW PHOTOGRAMMETRIC LAYOUT OF CAMERA STATIONS: A CASE STUDY
2015
This paper describes an easy and low cost photogrammetric method to determine the height of a point in relation to a reference plane. Such a method consists of an innovative geometric layout of the camera stations and specific algorithms. It is applicable to architectural surveying, in particular when the surface to be surveyed present a definitive geometry, with clearly identifiable defined points. The effectiveness of this method was verified through a case study carried out with the use of a digital camera and three dimensional targets. Two different pairs of images were obtained. One pair consists of images taken with a 35 mm and 19 mm focal length; the other one consists of images take…
A combined single range and single image device for low-cost measurement of building facade features
2008
The dimensions of building facades and window apertures are usually determined by making direct measurements using tapes and plummets. This approach, however, has a number of drawbacks including the physical risk to which the persons making the measurements are exposed. This paper proposes an indirect approach based on close range photogrammetry that is inexpensive, simple, fast and safe, and which does not require specialist staff or direct ground control measurements. The method is based on taking a picture using a digital camera and measuring the distance to the object using a handheld laser distance meter. Both items of equipment are mounted on a specially designed support that allows t…
Flow-bed interactions analysis and application of automatic close range digital photogrammetric survey in a laboratory flume
2014
This paper reports on a laboratory study in which the automatic digital photogrammetric survey was applied to derive the high-resolution Digital Surface Model (DSM) of the bed topography, used for the flow-bed interactions analysis, in a large amplitude meandering laboratory flume. The analysis has been conducted with the aid of detailed data of three-dimensional flow field previously collected using the acoustic Doppler velocity profiler DOP2000. The applied surveying procedure has allowed the evaluation of the DSM with a resolution of ±0.5 mm. The detailed DSM has been compared with peculiar maps describing the flow velocity pattern (downstream and the crossstream flows) and the shear vel…
BIFOCAL PAIRS OF IMAGES FOR LOW-COST SURVEY IN CLOSE RANGE PHOTOGRAMMETRY
2019
Abstract. This paper present a method for close range photogrammetry based on an camera positioning scheme in which two cameras capture an equal portion of an object at the same scale, but have different focal lengths and camera-to-object distances. This scheme is alternative to the stereoscopic scheme and is associated with a system of equations which permits one to calculate first the relief displacement of points on a photograph and then their relief relative to a reference plane. The obtained relief and relief displacement values can be used to produce low-cost orthophotographs by using software for image processing, which doesn’t need to be dedicated, but has to provide measurement and…