Geographic Information Systems
Spectral Angle Mapper


OpenCL Studio was used to develop a real time classification system for hyperspectral images based on the Spectral Angle Mapper (SAM) algorithm. Each pixel of the hyperspectral image used for this demo contains the intensities of 492 different wavelengths of light. The SAM algorithm performs a dot product between the intensity vector of a reference pixel and every other pixel in the image. If the angle is below a predefined threshold, then the pixel is considered to be of the same class as the reference, indicating that the underlying geographic features are similar. Using the 2D interface constructs of OpenCL Studio, an application was built to interactively select reference pixel, zoom into selected areas and adjust exposure and SAM thresholds.