ResearchSpace
→
Browsing by Author

Browsing by Author "Griffith, DJ"

Now showing items 1-13 of 13

Analysing real-world turbulence at low cost

Author: Mashaba, Nikiwe P ; Griffith, DJ Date: Nov 2020 Absorption, scattering and refractive index fluctuations are three primary phenomena contributing to optical turbulence. Temperature fluctuations, humidity and air velocity cause variations on both temporal and spatial, in the refractive ... Read more
Application of a commercial lidar-ceilometer to studies of aerosols in the atmospheric boundary layer

Author: Ramkilowan, A ; Griffith, DJ Date: Sep 2015 Ceilometers operating on several optical principles have been extensively applied to vertical visibility and cloud base measurements relating to aviation safety. The latest generation of laser time-of-flight backscatter ceilometers use the ... Read more
Characterizing optical filters for wildfire detectors

Author: Mashaba, Nikiwe P ; Griffith, DJ Date: Nov 2020 Near infrared detectors have gained popularity, mainly in the military, because of their capability of detecting wildfires. The Council for Scientific and Industrial Research (CSIR) focuses on the development and deployment of wildfire detectors ... Read more
Comparing optical turbulence using a pair of sonic anemometers

Author: Mashaba, Nikiwe P ; Griffith, DJ Date: Nov 2020 Turbulence is regarded as one of the most deleterious effects on imaging systems. The CSIR have an optical test facility, used to test image quality of surveillance systems, however, the temporal distribution of the near field turbulence is ... Read more
Comparison of slant-path scintillometry, sonic anemometry and high-speed videography for vertical profiling of turbulence in the atmospheric surface layer

Author: Griffith, DJ ; Sprung, D ; Sucher, E ; Ramkilowan, A ; Vhengani, L Date: Sep 2013 The optical effect of atmospheric turbulence greatly inhibits the achievable range of Detection, Recognition and Identification (DRI) of targets when using imaging sensors within the surface layer. Since turbulence tends to be worst near the ... Read more
Design philosophy and construction of a high concentration compound parabolic concentrator

Author: Roos, TH ; Maharajh, Dheepak M ; Griffith, DJ Date: Sep 2010 A compound parabolic concentrator (CPC) with a concentration ratio of 16:1 is under development at CSIR for volumetric receiver and solar fuels development. The ideal shape has been approximated by 6 and 12 facets in the longitudinal and ... Read more
Estimating uncertainty in resolution tests

Author: Goncalves, DP ; Griffith, DJ Date: May 2006 Resolution testing of imaging optical equipment is still commonly performed using the USAF 1951 target. The limiting resolution is normally calculated from the group and element that can just be resolved by an observer. Although resolution ... Read more
Exploration of satellite-derived data products for atmospheric turbulence studies

Author: Griffith, DJ ; Ramkilowan, A ; Sprung, D ; Sucher, E ; Willers, Cornelius J ; Coetzee, GJR ; Van Staden, R Date: Sep 2014 The quality, availability and diversity of satellite-derived earth observation data products are continuously improving. Such satellite products can provide an extensive and complementary view on many matters with respect to intensive but ... Read more
Investigation of optical turbulence in the atmospheric surface layer using scintillometer measurements along a slant path and comparison to ultrasonic anemometer measurements

Author: Sprung, D ; Sucher, E ; Ramkilowan, A ; Griffith, DJ Date: Sep 2014 Optical turbulence represented by the structure function parameter of the refractive index C(subn)(sup2) is a relevant parameter for the performance of electro-optical systems and characterization of the atmospheric influence on imaging. It ... Read more
Measurement of atmospheric MTF in a littoral environment

Author: Griffith, DJ ; Le Roux, FPJ ; Schwering, PBW ; Holloway, M Date: Sep 2008 Measurement of atmospheric modulation transfer function (MTF) derived from the point spread function is an alternative to the use of scintillometry in characterizing the effects of turbulence as well as optical scattering. This experiment ... Read more
Measurements of mirror soiling at a candidate CSP site

Author: Griffith, DJ ; Vhengani, L ; Maliage, M Date: Sep 2013 Loss of mirror reflectivity due to soiling at Concentrated Solar Power (CSP) plants is a significant consideration for design and operation of the plant. Increasingly, a bankable case for establishment of a new plant will include an evaluation ... Read more
Optical detectors for integration into a low cost radiometric device for in-water applications: HyDROW performance test at Loskop Dam

Author: Chetty, N ; Ramkilowan, A ; Griffith, DJ ; Lysko, MD Date: Apr 2013 South Africa’s fresh water resources are under threat by Harmful Algal Blooms (HABs). A comprehensive and cost effective method for wide area detection and monitoring of HABs is therefore needed to manage and where possible circumvent the ... Read more
Vicarious calibration campaign in Argentina for radiometric calibration of a multispectral imager onboard sumbandila satellite

Author: Griffith, DJ ; Horlent, M ; Ibañez, G ; Lysko, MD ; Lubbe, M ; Mudau, AE ; Torrusio, S ; Venkataraman, S ; Vhengani, LM Date: Jul 2011 Continuous assessment of the radiometric response of Earth Observation (EO) satellite imagers is necessary for the quality assurance of derived data products. With the launch of South Africa’s SumbandilaSat in September 2009, a number of ... Read more

Now showing items 1-13 of 13

Browse

All of ResearchSpace

Quick Links

Legislation and compliance

General Enquiries

Tel: + 27 12 841 2911
Email: callcentre@csir.co.za

Physical Address
Meiring Naudé Road
Brummeria
Pretoria
South Africa

Postal Address
PO Box 395
Pretoria 0001
South Africa

Social Connect

Resources on this site are free to download and reuse according to associated licensing provision. Please read the terms and conditions of usage of each resource.

Browsing by Author "Griffith, DJ"

Browsing by Author "Griffith, DJ"

Browse

All of ResearchSpace

Quick Links

Legislation and compliance

General Enquiries

Social Connect