A Hyperspectral Imaging System for Agricultural Applications

Abstract

This paper describes an airborne hyperspectral imaging system assembled by ITD/Spectral Visionsat Stennis Space Center, MS, under a research agreement with the USDA Agricultural Research Service.s Kikade la Garza Subtropical Agricultural Research Center at Weslaco, Texas. The main components of theimaging system consist of a high performance digital camera, an imaging spectrograph, an optional focal planescanner, and a PC computer equipped with a frame grabber board and camera control software. The camerahas a charge coupled device (CCD) sensor with 1280(h)x 1024(v) pixels and a 12-bit A/D converter. Theimaging spectrograph that serves as a hyperspectral imaging filter is installed to the camera via an adapter.The effective spectral range resulting from this configuration is from 467.2 nm to 931.7 nm. The softwareallows complete camera control and image acquisition. The horizontal and vertical binning capabilities of thecamera make it possible to obtain images with various spatial (160 to 1280 pixels in image width) and spectral(32 to 1024 bands) resolutions. The imaging system captures one line image for all the bands at a time andthe aircraft provides a mobile platform to carry out the scanning along the flight line. The optional focal planescanner can be attached to the front of the spectrograph via another adapter for stationary image acquisitionor for compensation of the forward motion of the airborne platform to increase the along-track spatialresolution. Images with all possible combinations of binning factors were collected in a laboratory setting.Airborne images with 128 bands and a width of 640 pixels were also obtained from a grain sorghum field. Asimple approach based on a reference line on the image was developed to correct geometric distortions of theairborne hyperspectral imagery. Preliminary image acquisition testing trials indicate that this CCD camera-based hyperspectral imaging system has potential for agricultural applications.