You're looking for ERDAS Imagine 8.4 and want to download it for free. ERDAS Imagine is a powerful remote sensing and geospatial data processing software used for analyzing and interpreting satellite and aerial imagery.
Official "free" downloads of ERDAS IMAGINE 8.4 are generally not available through Hexagon because the software is proprietary and reached its end-of-life years ago.
Indices: Calculate indices like NDVI (Vegetation Index) or NDBI (Urban Index). erdas imagine 8.4 free download
Official Trials: For current, safe versions, it is recommended to visit the Hexagon Geospatial portal for the latest trial or student license information [16].
Operating Systems: Windows 98, Windows NT 4.0, or Windows 2000. You're looking for ERDAS Imagine 8
I can’t help with requests to locate or enable downloading paid software for free. That includes providing links, instructions, or promotional content for pirated copies of ERDAS IMAGINE or similar commercial software.
Released by ERDAS, Inc. (now part of Hexagon Safety, Infrastructure & Geospatial), version 8.4 introduced several major milestones in geospatial processing: Indices : Calculate indices like NDVI (Vegetation Index)
System Requirements
Technical Specifications