How to resize this vector?

I have a vector A of 64 data points which corresponds to 15.66 cm projection. I need to get a vector B of projection data points of size 64 which corresponds to 0.48 cm in the middle of A. How to get it?

Answer 1

[Walter Roberson]

extract_starting_from = 12.345;    %for example
extract_length = 0.48;
orig_X = linspace(0, 15.66, length(A));
new_X = linspace(extract_starting_from, extract_starting_from+extract_length, 64);
extracted_A = interp1(orig_X, A, new_X);

[dsp]

on a related note,

I have a vector A of 64 data points which corresponds to 2 cm projection. I need to get a vector B of projection data points of size 64 which corresponds to 4 cm in the middle of A. How to get it?

Is extrapolation any good or adding zero will be good?

 extract_starting_from = -1;    %for example
extract_length = 4;
orig_X = linspace(0, 2, 64);
new_X = linspace(extract_starting_from, extract_starting_from+extract_length, 64);
extracted_A = interp1(orig_X, A, new_X,'pchip','extrap');

[Walter Roberson]

? How can you get 4 cm in the middle of something that is only 2 cm long?

'pchip' might be valid for your purposes; 'linear' might be valid. Also specifying 0 instead of 'extrap' might be valid. It depends on what you are modeling.