nibabel.ecat¶
Read ECAT format images
An ECAT format image consists of:
a main header;
at least one matrix list (mlist);
ECAT thinks of memory locations in terms of blocks. One block is 512 bytes. Thus block 1 starts at 0 bytes, block 2 at 512 bytes, and so on.
The matrix list is an array with one row per frame in the data.
Columns in the matrix list are:
0: Matrix identifier (frame number)
1: matrix data start block number (subheader followed by image data)
2: Last block number of matrix (image) data
3: Matrix status
1: hxists - rw
2: exists - ro
3: matrix deleted
There is one sub-header for each image frame (or matrix in the terminology above). A sub-header can also be called an image header. The sub-header is one block (512 bytes), and the frame (image) data follows.
There is very little documentation of the ECAT format, and many of the comments in this code come from a combination of trial and error and wild speculation.
XMedcon can read and write ECAT 6 format, and read ECAT 7 format: see
http://xmedcon.sourceforge.net and the ECAT files in the source of XMedCon,
currently libs/tpc/*ecat*
and source/m-ecat*
. Unfortunately XMedCon is
GPL and some of the header files are adapted from CTI files (called CTI code
below). It’s not clear what the licenses are for these files.
Functions
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Returns the order of the frames stored in the file Sometimes Frames are not stored in the file in chronological order, this can be used to extract frames in correct order |
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Returns framenumber of data as it was collected, as part of a series; not just the order of how it was stored in this or across other files |
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Class method to create image from filename filename |
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read (nframes, 4) matrix list array from fileobj |
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Retrieve all subheaders and return list of subheader recarrays |
Classes
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Class for basic Ecat PET header |
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Class returns a list of Ecat images, with one image(hdr/data) per frame |
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Ecat implemention of array proxy protocol |
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parses the subheaders in the ecat (.v) file there is one subheader for each frame in the ecat file |