scholarly journals Polymodal Method of Improving the Quality of Photogrammetric Images and Models

Energies ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3457
Author(s):  
Pawel Burdziakowski
Keyword(s):  
Unmanned Aerial Vehicles ◽  
Digital Terrain Model ◽  
Object Model ◽  
Quality Requirements ◽  
Terrain Model ◽  
Geometry Model ◽  
Digital Terrain ◽  
Lighting Conditions ◽  
Aerial Vehicles

Photogrammetry using unmanned aerial vehicles has become very popular and is already commonly used. The most frequent photogrammetry products are an orthoimage, digital terrain model and a 3D object model. When executing measurement flights, it may happen that there are unsuitable lighting conditions, and the flight itself is fast and not very stable. As a result, noise and blur appear on the images, and the images themselves can have too low of a resolution to satisfy the quality requirements for a photogrammetric product. In such cases, the obtained images are useless or will significantly reduce the quality of the end-product of low-level photogrammetry. A new polymodal method of improving measurement image quality has been proposed to avoid such issues. The method discussed in this article removes degrading factors from the images and, as a consequence, improves the geometric and interpretative quality of a photogrammetric product. The author analyzed 17 various image degradation cases, developed 34 models based on degraded and recovered images, and conducted an objective analysis of the quality of the recovered images and models. As evidenced, the result was a significant improvement in the interpretative quality of the images themselves and a better geometry model.

scholarly journals BADANIE MOŻLIWOŚCI WYKORZYSTANIA ZOBRAZOWAŃ DYNAMICZNYCH (WIDEO) Z NISKIEGO PUŁAPU LOTNICZEGO (BSP) DO OPRACOWAŃ FOTOGRAMETRYCZNYCH

1970 ◽  
pp. 53-64
Author(s):  
ADAM MŁYNARCZYK ◽  
SŁAWOMIR KRÓLEWICZ ◽  
PAWEŁ RUTKOWSKI
Keyword(s):  
High Altitude ◽  
Unmanned Aerial Vehicles ◽  
Point Cloud ◽  
Digital Terrain Model ◽  
Image Data ◽  
Terrain Model ◽  
Digital Terrain ◽  
Aerial Vehicles ◽  
The Creation ◽  
Recorded Image

The use of unmanned aerial vehicles is becoming more and more popular for making high-altitude and orthophotomap models. In this process, series of images are taken at specific intervals, usually lasting several seconds. This article demonstrates the ability to make models and orthophotomaps from dynamic images – video recorded from UAV. The best mutual coverage of photographs was indicated (95–96%) and the photogrammetric process for joining images was presented, through the creation of a point cloud to obtain a digital terrain model and the orotfotomap. The data was processed in 150 different variants and the usefulness of this method was demonstrated. Problems and errors that may occur during the processing of recorded image data are also described.

scholarly journals ASSESSMENT OF THE QUALITY OF DIGITAL TERRAIN MODEL PRODUCED FROM UNMANNED AERIAL SYSTEM IMAGERY

2016 ◽  
Vol XLI-B1 ◽  
pp. 893-899
Author(s):  
M. Kosmatin Fras ◽  
A. Kerin ◽  
M. Mesarič ◽  
V. Peterman ◽  
D. Grigillo
Keyword(s):  
Quality Assessment ◽  
Point Cloud ◽  
Digital Terrain Model ◽  
Quality Parameter ◽  
Unmanned Aerial System ◽  
Test Field ◽  
Absolute Deviation ◽  
Terrain Model ◽  
Digital Terrain

Production of digital terrain model (DTM) is one of the most usual tasks when processing photogrammetric point cloud generated from Unmanned Aerial System (UAS) imagery. The quality of the DTM produced in this way depends on different factors: the quality of imagery, image orientation and camera calibration, point cloud filtering, interpolation methods etc. However, the assessment of the real quality of DTM is very important for its further use and applications. In this paper we first describe the main steps of UAS imagery acquisition and processing based on practical test field survey and data. The main focus of this paper is to present the approach to DTM quality assessment and to give a practical example on the test field data. For data processing and DTM quality assessment presented in this paper mainly the in-house developed computer programs have been used. The quality of DTM comprises its accuracy, density, and completeness. Different accuracy measures like RMSE, median, normalized median absolute deviation and their confidence interval, quantiles are computed. The completeness of the DTM is very often overlooked quality parameter, but when DTM is produced from the point cloud this should not be neglected as some areas might be very sparsely covered by points. The original density is presented with density plot or map. The completeness is presented by the map of point density and the map of distances between grid points and terrain points. The results in the test area show great potential of the DTM produced from UAS imagery, in the sense of detailed representation of the terrain as well as good height accuracy.

scholarly journals Threat of Pollution Hotspots Reworking in River Systems: Case Study of the Ploučnice River (Czech Republic)

2019 ◽  
Vol 8 (1) ◽  
pp. 37 ◽  
Author(s):  
Jitka Elznicová ◽  
Tomáš Matys Grygar ◽  
Jan Popelka ◽  
Martin Sikora ◽  
Petr Novák ◽  
...  
Keyword(s):  
Laser Scanning ◽  
Digital Terrain Model ◽  
Terrain Model ◽  
Non Invasive ◽  
Digital Terrain ◽  
Quality Of Water ◽  
Lateral Channel ◽  
Floodplain Development ◽  
Channel Deposits

As fluvial pollution may endanger the quality of water and solids transported by rivers, mapping and evaluation of historically polluted fluvial sediments is an urgent topic. The Ploučnice River and its floodplain were polluted by local uranium mining from 1971–1989. We have studied this river since 2013 using a combination of diverse methods, including geoinformatics, to identify pollution hotspots in floodplains and to evaluate the potential for future reworking. Archival information on pollution history and past flooding was collected to understand floodplain dynamics and pollution heterogeneity. Subsequently, a digital terrain model based on laser scanning data and data analysis were used to identify the sites with river channel shifts. Finally, non-invasive geochemical mapping was employed, using portable X-ray fluorescence and gamma spectrometers. The resulting datasets were processed with geostatistical tools. One of the main outputs of the study was a detailed map of pollution distribution in the floodplain. The results showed a relationship between polluted sediment deposition, past channel shifts and floodplain development. We found that increased concentration of pollution occurred mainly in the cut-off meanders and lateral channel deposits from the mining period, the latter in danger of reworking (reconnecting to the river) in the coming decades.

scholarly journals Can analytical shading be art?

2015 ◽  
Vol 47 (3) ◽  
pp. 121-135
Author(s):  
Jerzy Siwek ◽  
Wojciech Wacławik
Keyword(s):  
Experimental Studies ◽  
Digital Terrain Model ◽  
Crucial Importance ◽  
Significant Similarity ◽  
Basic Principles ◽  
Factors Affecting ◽  
Terrain Model ◽  
Digital Terrain ◽  
Proper Generalization

Abstract Despite numerous theoretical and experimental studies of analytical relief shading, devised about half a century ago, its quality has not yet reached the excellence of traditional (manual) shading. The paper discusses its basic principles and the main factors affecting the quality of shading. It also stresses the crucial importance of the digital terrain model used as the basis for shading as well as the proper generalization of the relief. Experiments with shading modules of ArcGIS and Surfer, aiming to explore the functionality of algorithms they employ, have demonstrated significant similarity of the results. In conclusion, the authors attempt to answer the question posted in the title of the article. In their view, analytical shading is not art because shading algorithms are incapable of producing the visually beautiful effects that an experienced cartographer with artistic talents can create.

scholarly journals Analysis of the current state of unstable geomorphological structures with modern methods

2020 ◽  
Vol 13 (1) ◽  
pp. 195-199
Author(s):  
Vyacheslav V. Dolotov ◽  
Yuri N. Goryachkin ◽  
Andrey V. Dolotov
Keyword(s):  
Time Perspective ◽  
Digital Terrain Model ◽  
Aerial Photographs ◽  
Detailed Data ◽  
Terrain Model ◽  
Digital Terrain ◽  
Current State ◽  
The Status ◽  
The Mathematical Model

The paper gives results of the digitization of the status and spatial position of a cliff in the Western Crimea coastal zone. The modern equipment and methods accelerate the survey from the time perspective and improve the quality of the outcomes; namely a high precision GNSS receiver in RTK mode and PHANTOM-3 PRO copter. The digital terrain model was generated with used the Agisoft Photoscan software. The paper shows that the precision of the mathematical model of the relief constructed by aerial photographs provides more detailed data in comparison to those obtained in the field observations. Furthermore, aerial photography makes it possible to calculate the number of spatial characteristics of hazardous for surveying and latent natural objects out of reach for an on-location investigation. As a result, the very detailed data about current condition of dangerous cliff were obtained. The paper also evaluates the linear and volumetric characteristics of cleavages that are prone to collapse.

scholarly journals ACCURACY ASSESSMENT OF LIDAR-DERIVED DIGITAL TERRAIN MODEL (DTM) WITH DIFFERENT SLOPE AND CANOPY COVER IN TROPICAL FOREST REGION

2015 ◽  
Vol II-2/W2 ◽  
pp. 183-189 ◽  
Author(s):  
M. R. M. Salleh ◽  
Z. Ismail ◽  
M. Z. A. Rahman
Keyword(s):  
Tropical Forest ◽  
Digital Terrain Model ◽  
Canopy Cover ◽  
Airborne Lidar ◽  
Lidar Data ◽  
Terrain Model ◽  
Digital Terrain ◽  
Terrain Slope ◽  
Airborne Lidar Data

Airborne Light Detection and Ranging (LiDAR) technology has been widely used recent years especially in generating high accuracy of Digital Terrain Model (DTM). High density and good quality of airborne LiDAR data promises a high quality of DTM. This study focussing on the analysing the error associated with the density of vegetation cover (canopy cover) and terrain slope in a LiDAR derived-DTM value in a tropical forest environment in Bentong, State of Pahang, Malaysia. Airborne LiDAR data were collected can be consider as low density captured by Reigl system mounted on an aircraft. The ground filtering procedure use adaptive triangulation irregular network (ATIN) algorithm technique in producing ground points. Next, the ground control points (GCPs) used in generating the reference DTM and these DTM was used for slope classification and the point clouds belong to non-ground are then used in determining the relative percentage of canopy cover. The results show that terrain slope has high correlation for both study area (0.993 and 0.870) with the RMSE of the LiDAR-derived DTM. This is similar to canopy cover where high value of correlation (0.989 and 0.924) obtained. This indicates that the accuracy of airborne LiDAR-derived DTM is significantly affected by terrain slope and canopy caver of study area.

scholarly journals PREPROCESSING OF SATELLITE DATA FOR URBAN OBJECT EXTRACTION

2015 ◽  
Vol XL-3/W2 ◽  
pp. 115-120 ◽  
Author(s):  
T. Krauß
Keyword(s):  
Digital Terrain Model ◽  
Stereo Pair ◽  
Spectral Classification ◽  
Terrain Model ◽  
Digital Terrain ◽  
Digital Elevation ◽  
Elevation Model ◽  
Processing Steps

Very high resolution (VHR) DSMs (digital surface models) derived from stereo- or multi-stereo images from current VHR satellites like WorldView-2 or Pléiades can be produced up to the ground sampling distance (GSD) of the sensors in the range of 50 cm to 1 m. From such DSMs the digital terrain model (DTM) representing the ground and also a so called nDEM (normalized digital elevation model) describing the height of objects above the ground can be derived. In parallel these sensors deliver multispectral imagery which can be used for a spectral classification of the imagery. Fusion of the multispectral classification and the nDEM allows a simple classification and detection of urban objects. In further processing steps these detected urban objects can be modeled and exported in a suitable description language like CityGML. In this work we present the pre-processing steps up to the classification and detection of the urban objects. The modeling is not part of this work. The pre-processing steps described here cover briefly the coregistration of the input images and the generation of the DSM. In more detail the improvement of the DSM, the extraction of the DTM and nDEM, the multispectral classification and the object detection and extraction are explained. The methods described are applied to two test regions from two satellites: First the center of Munich acquired by WorldView-2 and second the center of Melbourne acquired by Pl´eiades. From both acquisitions a stereo-pair from the panchromatic bands is used for creation of the DSM and the pan-sharpened multispectral images are used for spectral classification. Finally the quality of the detected urban objects is discussed.

scholarly journals ASSESMENT OF THE INFLUENCE OF UAV IMAGE QUALITY ON THE ORTHOPHOTO PRODUCTION

2015 ◽  
Vol XL-1/W4 ◽  
pp. 1-8 ◽  
Author(s):  
D. Wierzbicki ◽  
M. Kedzierski ◽  
A. Fryskowska
Keyword(s):  
Large Scale ◽  
Digital Terrain Model ◽  
Image Data ◽  
Weather Conditions ◽  
Noticeable Increase ◽  
Terrain Model ◽  
Digital Terrain ◽  
Lighting Conditions ◽  
Terrain Models ◽  
Uav Image

Over the past years a noticeable increase of interest in using Unmanned Aerial Vehicles (UAV) for acquiring low altitude images has been observed. This method creates new possibilities of using geodata captured from low altitudes to generate large scale orthophotos. Because of comparatively low costs, UAV aerial surveying systems find many applications in photogrammetry and remote sensing. One of the most significant problems with automation of processing of image data acquired with this method is its low accuracy. This paper presents the following stages of acquisition and processing of images collected in various weather and lighting conditions: aerotriangulation, generating of Digital Terrain Models (DTMs), orthorectification and mosaicking. In the research a compact, non-metric camera, mounted on a fuselage powered by an electric motor was used. The tested area covered flat, agricultural and woodland terrains. Aerotriangulation and point cloud accuracy as well as generated digital terrain model and mosaic exactness were examined. Dense multiple image matching was used as a benchmark. The processing and analysis were carried out with INPHO UASMaster programme. Based on performed accuracy analysis it was stated that images acquired in poor weather conditions (cloudy, precipitation) degrade the final quality and accuracy of a photogrammetric product by an average of 25%.

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