Change the range of an array

i have a 50x50 matrix with a maximum value of 1000 and a minimum of 200. I am looking for a way to increase the minimum to 350 and scale up the values accordingly but keep the maximum 1000.

Any help is appreciated

Answer 1

[Rik]

Essentially your question is this:

Given an array A with values ranging between 200 and 1000

How to find p0 and p1 such that B has values between 350 and 1000 after performing

B=p0+p1*A;

I would suggest using polyfit or determining the values yourself. If you pick the two extreme values, that shouldn't be difficult.

Answer 2

[Walter Roberson]

formula = @(M) (M - 200)/(1000-200) .* (1000-350)  + 350

formula = function_handle with value:
    @(M)(M-200)/(1000-200).*(1000-350)+350

syms M
formula(M)

ans = 

subs(formula(M), M, 200:100:1000)

ans = 

So you could use the function handle for numeric work, or you could use the more direct but less obvious linear transformation shown as the symbolic formula

Answer 3

[Image Analyst]

Simply use rescale():

scaledMatrix = rescale(originalMatrix, 350, max(originalMatrix(:)));