reading complex data into a matlab array

18 次查看（过去 30 天）
Alex
Alex 2011-11-27
回答： Matthew Parry 2019-11-7
Hi,
To keep it short: How can you read complex doubles into a matlab array from raw data files. To keep it long, see below.
I have a raw data file taken from an MR scanner. I have been using the IDL language to read/reconstruct it but my files have become large and the memory management in IDL is no longer good enough. I need to know how to read this data into matlab. The problem is in the data-type. IDL can create complex double arrays but it seems matlab cannot. The data is arranged as follows: header-->data-->header-->data... etc. I know how many bytes the headers are so i can move a pointer using fseek/fread etc however I do not know how to read in the data into an array. Each data point is a 16 byte complex number. If I dont move the pointers correctly then the data becomes scrambled etc. The data parts are structured: real --> IM --> real --> IM and so on. When I read in 16 bytes into IDL I get the correct values. It would be so simple if there were a complex double datatype in matlab. I've thought about parsing the data as I read it into a real and im matrix and then combining them afterwards but there must be an easier way?

请先登录，再回答此问题。

采纳的回答

Jared
Jared 2011-11-27
If I understand the question correctly, something along these lines should work (although don't trust me on the fread syntax - it's been a while):
fp = fopen(file_of_interest);
% code for reading the header, etc.
complex_matrix = complex(ones(final_size),ones(final_size));
for i=1:length(complex_matrix(:))
complex_matrix(i) = complex(fread(fp,8,'*double'),fread(fp,8,'*double'));
end
% whatever other finalization you need to do
fclose(fp);
  2 个评论
A
A 2012-2-7
What part of this solves the header->data->header->data?
I'm dealing with the same issue but not complex numbers. What exactly is the '8' in fread(fp,8,'*double") telling it to do? In that spot I currently have my matrix size [4x4]. Is there a way to not read in the header parts?

请先登录，再进行评论。

更多回答（1 个）

Matthew Parry
Matthew Parry 2019-11-7
From R2019a onwards you can use the function readmatrix().

类别

在 Help Center 和 File Exchange 中查找有关 MRI 的更多信息

标签

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by