i# HyTools
HyTools is a python library for working with imaging spectroscopy data, with a focus on terrestrial scenes. At it's core it consists of a series of functions for reading and writing ENVI-formatted images in addition to opening NEON-formatted AOP HDF files. Built on top of these functions are a series of higher level processing tools for data analysis which include spectral resampling, topographic correction and BRDF correction. Other features are currently under development and include mask generation and MNF transformation.
We have also created a series of command line tools which string together the processing functions and provide a more streamlined workflow for processing images.
Dependencies
- numpy
- h5py
- gdal
Basic usage
import hytools as ht
hyObj = ht.openENVI('envi_file.bin')
#Loads image to a numpy memmap
hyObj.load_data()
#Calculate NDVI, retrieves closest wavelength to input lambda in nm
ir = hyObj.get_wave(900)
red = hyObj.get_wave(660)
ndvi = (ir-red)/(ir+red)
#Other options for retrieving data
band = hyObj.get_band(10)
column = hyObj.get_column
line = hyObj.get_line
chunk = hyObj.get_chunk(x1,x2,y1,y2)Examples
BRDF Correction
The BRDF correction module consists of a series of tools for removing brightness gradients caused by variation in solar and viewing geometry. The module uses the combination of the Ross and Li kernels to model the volumetric, geometric and isometric scattering surfaces and applies a multiplicative correction to remove brightness gradients.
Topographic Correction
The topographic correction module uses the Sun-Canopy-Sensor (SCS+C) method developed by Soenen et al. 2005 to remove shadows caused by variation in topography.
