27-07-2012, 03:16 PM
Image Processing for MRI
[attachment=29289]
16 bits are not enough precision
16 bit analogue to digital converter
integers 0 – 65535.
True dynamic range is higher (variable attenuators in receiver chain).
Complex FFT and other processing.
Use “intensity” image (floating point values), rather than indexed or rgb.
avoid read/writing intermediate files in tiff, gif.
Vertical axis reflection
Care mapping:
spatial transformations
k-space frequencies
File Formats
Files contain: Information and pixel values.
Information in either:
fixed length header (gipl)
fixed length separate file (Analyze)
tags (ACR/NEMA, tiff, DICOM, SPI)
Decoding a DICOM directory
Thousands of files often with meaningless names.
Set up DICOM node to use sensible file names.
Examine the slice separations in 3D space using ImagePositionPatient.
for cardiac phases, use TriggerDelay?
Future standard: Multi-frame DICOM objects for MR. Also allow annotation for tractography, fMRI etc.
[attachment=29289]
16 bits are not enough precision
16 bit analogue to digital converter
integers 0 – 65535.
True dynamic range is higher (variable attenuators in receiver chain).
Complex FFT and other processing.
Use “intensity” image (floating point values), rather than indexed or rgb.
avoid read/writing intermediate files in tiff, gif.
Vertical axis reflection
Care mapping:
spatial transformations
k-space frequencies
File Formats
Files contain: Information and pixel values.
Information in either:
fixed length header (gipl)
fixed length separate file (Analyze)
tags (ACR/NEMA, tiff, DICOM, SPI)
Decoding a DICOM directory
Thousands of files often with meaningless names.
Set up DICOM node to use sensible file names.
Examine the slice separations in 3D space using ImagePositionPatient.
for cardiac phases, use TriggerDelay?
Future standard: Multi-frame DICOM objects for MR. Also allow annotation for tractography, fMRI etc.