I want to understand how to read this code

A = xlsread('experiment.xlsx','A','A12:XP523');
Tmin = 24;
Tmax = 37;
save('fields','Tmin','Tmax');
IA = im2uint16(mat2gray(A,[Tmin Tmax]));
imwrite(IA,'A.tiff', 'tiff');

This is total program. I have image A and excel file experiment.xlsx. experiment.xlsx have 523 rows and A-XP columns. Now I want to know,

(mat2gray(A, [amin amax]) function means convert matrix A into image and Tmin, Tmax are the range of matrix A minimum to A maximum I am right? matrix A mean sheet in the excel file having all column (A-XP Columss and 523 rows) and rows?

[DGM]

Duplicate of

https://www.mathworks.com/matlabcentral/answers/1740790-i-want-to-meaning-of-this-code-i-do-not-understand