Akira KOBAYASHI

Research on Decrease of Shadow Area in City Part Aerial Photograph Image

Atushi RIKIMARU Yukio MUKAI Kazuyoshi TAKAHASI

Recently, the valuation of fixed assets came to be executed by using the aerial photograph. But it is hoped to decrease the shadow because it is difficult to recognize to geographic information according to the influence of the shadow.
In this research, the examination of the image processing technology was executed aiming to recognize the shadow area included digitalized city part aerial photograph image and restore original geographic information.
In this research, the shadow area is restored after the shadow is recognized. At first, the color balance of the aerial photograph image has been adjusted, and various index images were made, and the shadow area has been extracted by the trial by using the cluster analysis, and the shadow area has been extracted by the histogram, and detailed area pixel of shadow area was removed by the labeling processing, and the shadow area was corrected by using the method by the statistic conversion and the automatic sampling.
The subjective factor was reduced by extracting the shadow area by the histogram. It improved the efficiency of the analysis by automating the shadow area correction. In addition, it is hoped to examination of threshold decision technique of histogram and to improve the accuracy of the sampling.