Aerial Photogrammetry Method for Water Quality Monitoring Using Digital Camera

ABSTRACT

Environmental monitoring through the method of traditional ship sampling is time consuming and requires a high survey cost. This study uses an empirical model, based on actual water quality of total suspended solids (TSS) measurements from the Prai River estuary Penang, Malaysia, to predict TSS based on optical properties of digital camera imagery. The proposed algorithm is based on the reflectance model that is a function of the inherent optical properties of water, which can be related to its constituent’s concentrations. Water samples were simultaneously collected with the airborne image acquisition and analyzed later in the laboratory. These locations were determined by using a handheld GPS. The digital numbers for each band were extracted corresponding to the sea-truth locations and were later used for calibration of the water quality algorithm. The efficiency of the proposed algorithm was investigated, based on the observations of correlation coefficient (R) and root-mean-square deviations (RMS) with the sea-truth data. This algorithm was then used to map the TSS concentration in Prai River estuary, Penang, Malaysia. The TSS map was color-coded and geometrically corrected for visual interpretation. This study indicates that TSS mapping can be carried out using digital camera imageries.