How to change the pixel values without using for-loop ?

Question

Priyanka Roy 2015-4-22

评论： Richard Hall 2020-3-15

let i have a image matrix like : A =

 200   250   254   225
 235   226   227     1
 249   225    29     1
  82    92   222   224
 252   229   255   255

I want to change the values within range 240 to 255 into 0 without using for-loop The output array or matrix will be : A =

 200   0     0     225
 235   226   227     1
  0     225   29     1
  82    92   222   224
   0   229   0      0

how will I calculate it ?

Stephen23 2015-4-22

Such basic MATLAB usage is taught in these tutorials:

And certainly it is covered by "Logical Indexing – Example 1" here:

Answer 1

Guillaume 2015-4-22

编辑：Guillaume 2015-4-22

This is a basic matrix operation that I'm sure is covered in Getting started:

A(A >= 240) = 0

Priyanka Roy 2015-4-22

Thanks :)

Richard Hall 2020-3-15

That "basic matric operation" is not in "Getting Started".