An Evaluation on Different Number of Ground Control Points in Unmanned Aerial Vehicle Photogrammetric Block

Abstract

ABSTRACT:This paper presents a novel method of unmanned aerial vehicle image processing using photogrammetric technique. The study area consist different slope class which involves undulating area around the Skudai area, Malaysia. All photogrammetric methods were applied in this study including selection of test area, flight planning, camera calibration and image processing orientation. A new ground control point configurations is introduced in this study as a generic approach in unmanned aerial vehicle photogrammetric block. These configurations are used to determine the best photogrammetric results based on number of ground control points in the photogrammetric block during image processing. The objective of this study is to determine the best configuration for photogrammetric block in order to produce the best photogrammetric products. Photogrammetric image processing involves two main orientations which are known as interior orientation and exterior orientation. Interior orientation involves the parameters of camera in order to calibrate the image in the same position as during the image acquisition. Exterior orientation involves the measurement of tie points to tie up all images in the strips until photogrammetric block. In this study, six ground control point configurations were tested to determine the best photogrammetric results. In this study, two main photogrammetric results were produced namely digital orthophoto and digital elevation model. The verification results show that all configurations recorded coefficient percentage of more than 97 % accuracy for the six configurations. The validation results conclude that ground control point plays an important role in photogrammetric block to acquire the accurate photogrammetric results. In this study eight and nine ground control point configurations are the best configurations among the others. Qualitatively, vector plot error for easting and northing coordinates can be viewed graphically to distinguish the error and direction for all configurations which has been proposed in this study.

Accuracy of Photogrammetric UAV-Based Point Clouds under Conditions of Partially-Open Forest Canopy

“…Additionally, the abovementioned authors suggest the use of a higher number of GCPs [51,52]. Tahar [54] tested GCP configurations very similar to those presented in our study and acquired the best results using 8-9 GCPs.…”

Accuracy Assessment of Digital Surface Models from Unmanned Aerial Vehicles’ Imagery on Glaciers

“…They also showed that DSM accuracy is higher when the GCPs are installed in a way that they are visible on many images. The studies of Tahar et al [27], Tahar [28], as well as Rosnell and Honkavaara [29] also concluded that DSM accuracy increases with increasing number of GCPs. A similar conclusion was made in the study of Tonkin and Midgley [30], who additionally showed that when a certain number of GCPs is reached, the DSM accuracy does not increases further.…”

Spatio-temporal evaluation of plant height in corn via unmanned aerial systems

“…The importance and the number of GCPs necessary to ensure accuracy of UAS image construction have been previously discussed by other researchers. [46][47][48] In terms of geometric quality, the accumulated horizontal and vertical error was 0.7 cm∕pixel in orthomosaic and CSM from 2-weeks prior to flowering, and 0.5 cm∕pixel for the flowering raster products. Furthermore, a woody table (dimensions ¼ 0.8 m length × 0.4 m wide × 0.6 m height) was used for nonvegetation geometric evaluation.…”