"Undefined variable" error even though variable is defined
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LaraS
el 22 de Feb. de 2024
Respondida: Steven Lord
el 23 de Feb. de 2024
I'm using part of a code I borrowed from @imageanalyst where I'm trying to run through frames of a video to look at how the intensity changes over time. I'd like to perform a background subtraction with the code below
if frame1 == 1
Background1 = thisFrame1;
else
for t=1:frame1
% Change background slightly at each frame
Background1 = (1-alpha1)* thisFrame1 + alpha1 * Background1;
end
end
I get an error stating:
"Unrecognized function or variable 'Background1'.
Background1 = (1-alpha1)* thisFrame1 + alpha1 * Background1;"
even though I have the function defined. when I run the same line of code with a different file, it works fine, even though they're the same file type. any idea as to why this is happening? thanks!
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Steven Lord
el 23 de Feb. de 2024
I'm guessing that you want to initialize Background1 when t is equal to 1 and to use the formula to update Background1 when t is greater than 1. In that case:
for t=1:frame1
if t == 1
Background1 = thisFrame1;
else
% Change background slightly at each frame
Background1 = (1-alpha1)* thisFrame1 + alpha1 * Background1;
end
end
Except that when t is 2, Background1 will be (1-alpha1)*thisFrame1 + alpha1*thisFrame1 = thisFrame1 (assuming there's no code later in the for loop after the if / else block that changes Background1. So perhaps if you describe in more detail what you want to do we can suggest some modifications to your code to achieve your goal.
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Más respuestas (1)
Walter Roberson
el 23 de Feb. de 2024
if frame1 == 1
Background1 = thisFrame1;
else
This does not define Background1 if frame1 ~= 1
4 comentarios
DGM
el 23 de Feb. de 2024
Well without knowing what the code or process is, there really isn't much I can suggest.
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