DIRSIG

One of the more interesting areas of development right now for laser radar are "waveform" LIDAR systems. Unlike Linear-mode (Lm) or Geiger-mode (Gm) system that collect a relatively small number of height measurements per GSD, a "waveform" LIDAR (wLIDAR) essentially digitizes the returned flux during the time window at some time resolution. That means you have intensity information at all the ranges rather than just a discrete set of them. This allows for some very complex post-processing of the data. The "Airborne Taxonomic Mapping System" (AToMS) operated by the Carnegie Airborne Observatory (CAO) is being used to better quantify the biomass in complex tree canopies and grasslands. The remote sensing arm of the National Ecological Observatory Network (NEON) plans on operating a wLIDAR on it's Airborne Observation Platform (AOP). Most wLIDAR systems feature a high performance, single-pixel detector coupled to a high performance digitizer. To ob...

Many users want just raw radiance data from DIRSIG.  Rather than apply a built-in instrument model, they do their own post-processing of the radiance results.  The "Raw" capture method can be used to achieve this.  It writes raw DIRSIG results without applying any spatial or spectral integration. Here's a snapshot of the Raw Capture Method configuration dialog.  We'll now work through each section.   The Spectral Range controls the wavelengths for which DIRSIG will calculate and output results.   In this example, DIRSIG will compute from 0.40 microns to 2.50 microns in 0.01 micron increments.  The output image will have 211 bands of result data.  The delta must divide the range in to a whole number of bins.  For example, the range 0.4 to 0.7 microns with a 0.2 micron delta will result in an error message when DIRSIG runs. The Spatial Response controls how many results are computed and written out per detector array element....

We are often asked what programs can view DIRSIG's image outputs and how to import the raw DIRSIG image data files into other tools for further processing. For basic image viewing, DIRSIG-4.4.0 now includes a very simple viewing tool. Launch it from the main simulation editor window by selecting the "Start image viewer" option from the "Tools" menu. If you run your simulation from the GUI simulation editor, new image files are automatically added to the list in the image viewer as they are generated. If you want to manually add files to the list, simply select the "Open" item from the "File" menu or the toolbar. Here is a screenshot of the main image viewer window. The top part contains the list of currently opened files and the bands within those image files. To view a single band as a gray-scale image, choose "Single Band Display" from the combo box and then click on the image band that you want. Finally, click "Load Band...