1. A computer system for analyzing remotely sensed aerial photos in order to differentiate different types of vegetation, comprising: a computer readable memory for storing programmed instructions that can be executed by a processor; one or more processors that execute the programmed instructions in order to: receive digital aerial photo data for a region of interest; stretch near infrared (NIR) data from the digital aerial photo data to increase a variation of NIR values that represent items of interest in the digital aerial photo; compute Objective-based Vegetation Index (OVI) values using the stretched NIR data; and identify different types of vegetation in the digital aerial photo using OVI values computed from the stretched NIR data values.