Development of method for acquiring estimated vegetation index with higher accuracy from photo images by commercial digital cameras

2017 Fiscal Year Final Research Report

• Project/Area Number: 26450367
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Agricultural environmental engineering/Agricultural information engineering
• Research Institution: International Christian University
• Principal Investigator: OSAKI Keiji 国際基督教大学, 教養学部, 客員教授 (60160834)
• Project Period (FY): 2014-04-01 – 2018-03-31
• Keywords: 植生指標 / デジタルカメラ画像 / 近赤外領域 / 分光反射率 / 影領域 / 適正露光範囲

Outline of Final Research Achievements

Digital cameras are indispensable devices for proximal remote sensing technology and show an excellent advantage that they can cover more extensive areas by one shot than a spectral radiometer can make a measurement of a target object in a limited scope. When we make a distribution map of "vegetation index (shows an activity of photosynthesis by chlorophyll)" estimated from the images captured by commercial digital cameras with an auto exposure function on, it is sometimes seen that the areas with anomalously high values of vegetation index appear corresponding to darkest shadow areas in visible light images.
To remove the anomalous areas, we set the minimum threshold luminance of the image and found it very effective to exclude the pixels with the luminance below this threshold value from the processing of estimation of the vegetation index. It was also revealed that the minimum threshold luminance has dependence on gamma values of the image.

Free Research Field

画像計測光学、近接リモートセンシング、農業情報