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Saving a Bilevel - or Binary Image

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Matthew Moynihan
Matthew Moynihan on 26 Jan 2011
Hello,
I am creating a black and white movie in my code. I create a 4 dimensional matrix of zeros. Each number in the matrix is a uint8. This is the problem.
B = zeros(X, Y, 1, NumberOfFrames);
B = uint8(B);
All I want to save is a 1 and a 0. By doing a unit8 I add 7 extra bits to each pixel. This is over a 25 minute mov file!! How can I save the information using less memory? Is there for example an:
B = binary(B);
Command?
Thanks!

Answers (2)

Sean de Wolski
Sean de Wolski on 26 Jan 2011
B = false(X, Y, 1, NumberOfFrames); %casts as logical (1bit)
or
B = logical(B); %for something already in black and white but not 1bit

Siddharth Shankar
Siddharth Shankar on 26 Jan 2011
B = zeros(X, Y, 1, NumberOfFrames);
B = logical(B);
is what you are looking for. More info here: Logical Types
  3 Comments
Siddharth Shankar
Siddharth Shankar on 27 Jan 2011
Sean, the code provided above is by no means meant to be "best practice" or the "best way" to do something. I was simply working off the code that "justthebasics" provided. The key was to make him aware of the LOGICAL function.

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