Not all lineaments are detectable on unenhanced imagery.  A variety of  image processing techniques are used to highlight linear features of images. 
Known techniques like linear stretching, directional filtering, band ratioing and principal component analysis,  have been applied to enhance images for visual interpretation. 
Examples of the effects of digital image processing on TM image are shown here.
Enhanced images have been studied by the interpreter and the ones most appropriate for lineament detection (recognition)  have been chosen.

TM band 5 geocoded and radiometrically corrected

Linear contrast stretching technique applied on TM band 5

Low pass filter applied on TM band 5

Sobel edge detector filter applied on TM band 5

Band ratioing (band5/band1) applied on TM image 

Component 3, result of principal component analysis  on TM image

Color composite 3,2,1 (RGB). TM bands 1 2 and 3 have been enhanced using decorrelation stretching technique

Color composite 5,7,4 (RGB).
TM band5 has been processed using a north directional filter, band 7 using an east directional filter and band4 using a southwest directional filter