# Replace values to create an image with binary values (0,1)

4 views (last 30 days)
Amjad Iqbal on 21 Feb 2022
Commented: Amjad Iqbal on 21 Feb 2022
Dear Researchers,
I have a matrix (2D image) which I need to replace values in such a way to obtain binary image.
I used Max function which replace values for one condition. However, In this case, I need to replace values greater and less than zero with zero (0) and replace all values = zero with 1.
I have uploaded image, vaues are ranging from (-3.8 to 3.8), can you please guide me on how to obtain binary image.

Image Analyst on 21 Feb 2022
OK, now that you've added the .mat file, there are no values that are exactly 0. You need to define a range.
V = s.V;
subplot(2, 2, 1);
imshow(V, []);
colorbar
subplot(2, 2, 3:4);
histogram(V, 256);
grid on;
title('Histogram of V')
xlabel('Value')
ylabel('Count')
% There are no values that are exactly zero so let's pick a tolerance
tolerance = 0.1;
binaryImage = abs(V) < tolerance;
subplot(2, 2, 2);
imshow(binaryImage, []);
Amjad Iqbal on 21 Feb 2022
Perfect, It works, with what i required, now it's all about siffting and get more accurate results.
Many thanks dear @Image Analys

Cris LaPierre on 21 Feb 2022
Sounds like a logical result would work.
a = [-3.8 -1 0 1 3.8];
c = a~=1
c = 1×5 logical array
1 1 1 0 1
Cris LaPierre on 21 Feb 2022
The challenge I see is that none of your data values exactly equal 1. You'll need to look at your data and decide what range of values you want to consider to represent land.

Image Analyst on 21 Feb 2022
" I need to replace values greater and less than zero with zero (0) and replace all values = zero with 1. "
So why don't you just do
outputMatrix = inputMatrix == 0;

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