Multispectral sensors calibration for lightweight UAV

Abstract

Using a suitable gimbal sensor, a lightweight multispectral sensor weight less than 500 g, such as visible imagery in the 400-700 nm (4000x3000 pixels), NIR imagery in the 520-920 nm region (2048 x 1536 pixels) and thermal 8-14μm (160x120 pixels) were placed on low-cost Hexacopter UAVs to perform aerial acquisitions of oil palm plant at very low altitude. Reliability data analysis is generated from the correction of undesirable and defect of sensor characteristics. Here, the sensor correction and calibration such as geometric, radiometric, vignetting, resolution and directional effects. Radiometric calibration using an upwelling water methodology where with thermosensor, the coefficient of determination, R2 = 1 and without thermosensor, R2 = 0.9455. For multi-temporal or multi-sensor image analysis, relative DN-to-radiance radiometric calibration was performed by using the white material as calibration, then convert the other colored area without the material based on the ratio of the white panel area and the color reflected in that area and compatible with in-situ spectroscopy device.