Abstract
Aerial photographs taken by using color films are utilized extensively and frequently in the environmental survey of ports and harbor areas. However, as to the human visual inspection and photointerpretation, their capabilities are limited, and it is fairly difficult to discern from the delicate densities of color photographs the turbidities and hydrodynamic phenomena in ports and harbors. Many items of effective information may conceivably be overlooked.
The present research is concerned with the digitizing of aerial photographs, treatment of them as multi-spectral data having three wavelength bands in the visual light region of red, green, blue colors, followed by subjecting the resultant data to image processing and statistical analysis. By carrying out such processes, it is intended to extract the potentialies inherent in aerial photographs and to male them serve furthermore as the means of environmental surveys in ports and harbors.
The results of the present research are summarrized as follows.
1) Although quantization of images ideally performed by histogram representation, very few data on red color components are available in the case of the information on surface water bodies. This leads to the deficiency of information therein, which requires alteration of the specification of films sensitometric characteristics.
2) False color image are helpful in visual inspection and photointerpretation. For the photointerpretation of turbidities in surface water bodies, a combination consisting of assigning respectively each of B, G and R color wavelength bands to each of R, G and B color image planes proved to be effective.
3) Eigenvalues and contribution factors, derived from the analysis of principal components, show the possibility of the intensive treatment of data. The score diagrams analyzing the turbidities of ports and harbor
