Obtain normal file from images by Photometric Stereo:

**************************************
Notice:
First, lights direction MUST be save into a txt file named "lightDirection.txt", each line records an uniform lighting direction vector; If there are total N light sources, then total line number of lightDirection.txt should be N;
Second, all input images must be under the same format, and must have uniform name but followed by an unique and successive order number which starts from one. For example, if there are total N lights sources, then total corresponding images must name as (suppose the uniform name is "S", format is .bmp): S1.bmp,S2.bmp,...,SN.bmp;
Third, all images and the lightDirection.txt MUST be on the same folder.
**************************************

Step 1: run norFromPS;
Step 2: as required in the command window "Enter the path of the folder containing PS images and lightDirection.txt:", enter the folder's path, for example, if "lightDirection.txt" and all images are in "D:\dataset\PS_data", then enter D:\dataset\PS_data and press the "Enter" key to continue.
Step 3: as required in the command window "Enter the name of images without suffix and order number:", enter the uniform name of all images, for images "S1.bmp,S2.bmp,...,SN.bmp", enter S and press "Enter" key to continue.
Step 4: as required in the command window "Enter image suffix whithout dot:", suppose the images' format is .bmp, enter bmp (WITHOUT dot) and press "Enter" key to continue.
Step 5: final output is the normal file named "normal.txt" stored in the given foler in Step 2. This file is satisfied the format requirement by "DGP_surfFromNor.m", and each normal vector recorded is uniform.


**************************************************************************
An example to illustrated:(supposelightDirection.txt and images named s1.tif,..,s7.tif are stored in D:\dataset\PS_data)

Enter the path of the folder containing PS images and lightDirection.txt:
D:\dataset\PS_data
Enter the name of images without suffix and order number:
s
Enter image suffix whithout dot:
tif
Done!
**************************************************************************