Use Of Low-cost Cameras Research Articles

3D Reconstruction of rock paintings: a cost-effective approach based on modern photogrammetry for rapidly mapping archaeological findings

The work describes a cost-effective methodology for the creation of 3D virtual models with both metric and photo-realistic content developed for archaeologists who need to rapidly map new findings during their field prospections. The potential of modern photogrammetry approach, based on Structure from Motion (SfM) and dense image matching algorithms, coupled with the use of low-cost cameras is evaluated for the creation of 3D models and orthophotos of rock paintings. The case study is located in Brealito valley, in the Calchaqui basin of the Province of Salta, Argentina. In these wide areas, actually known for the naturalistic value, a huge amount of archeological remains was found and surveyed for the first time in August 2013 within a research project funded by the Italian Ministry of Foreign Affairs. A methodological approach to record the findings in a cost-effective and reliable way is defined, acquisitions are performed with common use instruments such as digital cameras (off-the-shelf and single lens reflex - SLR) and measuring tapes. The novelty of the work lies in defining, experiencing and transferring to operators a simple methodology for digitizing and mapping the archeological heritage in order to provide 2D orthophotos and 3D models. Such methodology allows anyone, archaeologists or unprofessional personnel, to be trained and easily perform a survey in order to document, survey and study the investigated site.

Testing the value of low-cost Structure-from-Motion (SfM) photogrammetry for metric and visual analysis of rock art

The discussion of digital photogrammetry and/or 3D laser scanning for recording the geometry of rock art sites is not new, but the production of high-quality 3D models requires great expenditure and specialized personnel that are not accessible to everyone or applicable to all sites. While the use of low-cost cameras and photogrammetry has been suggested as an alternative for fast visualization of rock art, do the results have enough quality for the metric and visual analysis of the art? This paper explores the potential of low-cost Structure-from-Motion (SfM) photogrammetry performed by non-professional surveyors, with no camera calibration and no tripod to speed the process, as an alternative cost-effective tool for quantitative and qualitative analysis of rock art. The innovative aspect of this paper is that we have verified the metric accuracy and graphic quality of low-cost 3D models and shown that they can be used as an effective low-cost tool for detailed analysis and tracing of rock art.

Development of a visual monitoring system for water balance estimation of horticultural crops using low cost cameras

The use of low cost cameras has been extended in all fields of technology in general, and agricultural applications in particular. Images provide useful information on the growing state of horticultural crops, which allow an accurate estimation of water balance and, hence, precise irrigation scheduling. In all of these cases, the temporary images of a crop can provide the percentage of green cover (PCG). This data is calibrated with the irrigation water amount that the crop needs for growing. Therefore, the use of visual monitoring systems in agriculture may reduce water consumption and increase productivity. In this paper, a novel system is presented using low cost cameras and a client-server architecture. It is composed of a set of inexpensive camera modules which communicate with a cloud computing server. Camera modules have been developed using open standard Arduino components; they are able to work independently, with their own connectivity, storage and power supply. On the other hand, the server is responsible for configuring these modules, performing computer vision algorithms and water balance estimation, storing all data in a secure database, and interacting with the user interface using the web. The final result is a complete and inexpensive system that allows continuous monitoring of the state of the crops, providing the user with valuable information about water balance for irrigation management. The proposed method achieves a high accuracy in the estimation of PGC, with an average error below 5%, requiring less than 2s of processing time per image in the server. This is transformed into an error in the computation of the crop coefficient below 1%. Technical details on the hardware and software components of the system are presented. Finally, advantages and weaknesses of the proposed solution are discussed, drawing new lines for future research.

Wave Run-Up Monitoring on Rubble-Mound Breakwaters Using a Photogrammetric Methodology

AbstractWave overtopping in rubble-mound breakwaters is an aspect that must be controlled in order to ensure the correct operation of port facilities. This manuscript shows a photogrammetric methodology to automatically monitor this process based on the use of low-cost cameras. Cameras are used for acquiring video of breakwaters. Then, image processing algorithms based on binarization tresholding and projective transformation, combined with geometric data of the structure provided by the facility manager, are used to evaluate the run-up height and automatically detect the existence or absence of a overtopping event. The methodology was successfully tested in the outer port of Punta Langosteira, A Coruna, Spain.