Lab 4: Enhancing imagery (Due by 4pm Feb 16)

Introduction

In this lab you will learn how enhance satellite imagery using spatial, spectral, and radiometric techniques.

Instructions

Read pages 129-164 of the Erdas Field Guide.  Open the Tour Guide and skim Chapter 11. For this lab, you will have to copy the following files to your working folder. You can find these files in I:\Students\Instructors\Geoffrey_Duh\GEOG4581\Lab4. The lab data files are also in the C:\Program Files\IMAGINE 8.7\examples folder on the lab computers.

dmtm.img

lanier.img

loplakebedsig357.img

panAtlanta.img

tmAtlanta.img

Complete the tutorial exercise in Chapter 11 and produce pictures of the following images - convolve, crisp, reverse, inverse, tassled, and mineral. Make sure you clearly annotate the pictures and submit them with your report.  Answer the questions at the end of this exercise.

Additional Notes

1.      When doing “subsetting an image without snapping”, you won’t be able to keep the coordinates you typed in. However, the more you zoom in on the image, the less displacement of the coordinates you will get. Make sure you zoom in enough to see individual pixels, so that you can see the effects of subsetting an image with and without snapping.

Questions

  1. What is "snapping to raster" when subsetting an image? Make two figures showing the effects of subsetting with and without snapping. The figures must show blowup views of one corner of the inquire box superimposed on the subset and original images.
  2. Click on the AOI tool within the subset dialogue and explain the three different options and the different results you get using each.
  3. Write a paragraph describing the concept of convolution to the lay person.
  4. Fill the table with the coefficients of a 3 x 3 Edge Detect filter.

 

 

 

 

 

 

 

 

 
  1. What are the layers of a tassled TM image? Describe what several features (e.g., water, urban, forested, and agricultural) look like in the false-color tasseled image and why they look that way.