Search found 9 matches

by alanxz
Thu, 2012-09-06, 20:02
Forum: DCMTK - General
Topic: DicomImage ignores Rescale values in Per-Frame Sequence
Replies: 2
Views: 3523

Re: DicomImage ignores Rescale values in Per-Frame Sequence

That's essentially what I ended up doing as a workaround. Also useful as older Philips MR scanners like to save away the rescale data in a different tag (2005,"Philips MR Imaging 005",09), (2005,"Philips MR Imaging 005",0a), in addition to that, even older versions of the scanner...
by alanxz
Thu, 2012-09-06, 17:06
Forum: DCMTK - General
Topic: DicomImage ignores Rescale values in Per-Frame Sequence
Replies: 2
Views: 3523

DicomImage ignores Rescale values in Per-Frame Sequence

Not sure if this is by-design or a bug: the DicomImage class ignores RescaleSlope/Rescale Intercept values if they're in the PerFrameFunctionalGroupsSequence.

Philips MR scanners like to put the RescaleSlope and RescaleIntercept tags in the PerFrameFunctionalGroupsSequence for Enhanced MR Images
by alanxz
Wed, 2012-09-05, 22:16
Forum: DCMTK - General
Topic: DcmItem::findAndGetString with PrivateTag range
Replies: 0
Views: 13831

DcmItem::findAndGetString with PrivateTag range

Is it possible to use DcmItem::findAndGetString() and related functions with a private tag (declared with a DcmTag object) that is defined with the upper byte left as empty in the data dictionary? E.g., its entry in private.dic looks like: (2005,"Philips MR Imaging DD 001",0a) In the dicom...
by alanxz
Mon, 2012-08-13, 21:17
Forum: DCMTK - General
Topic: Performing modality transform in floating point
Replies: 2
Views: 3131

Re: Performing modality transform in floating point

Couldn't figure out a way to do this without modifying the library code itself, so that's what I ended up doing. For the next person that stumbles upon this here's the code in question. https://github.com/alanxz/dcmtk You'll want the floating_internal_rep branch, which contains a single commit based...
by alanxz
Tue, 2012-08-07, 15:57
Forum: DCMTK - General
Topic: Performing modality transform in floating point
Replies: 2
Views: 3131

Performing modality transform in floating point

I have a program that represents pixel data internally as floating point values. I would like to read a DICOM image, then perform the modality transform in floating point and end up with floating point pixel data. Whats the best way to do this in DCMTK? I've looked into starting with the DicomImage ...
by alanxz
Mon, 2012-07-30, 20:36
Forum: DCMTK - General
Topic: FileFormat/Dataset read performance
Replies: 6
Views: 7715

Re: FileFormat/Dataset read performance

For future reference, here's a quick rundown of things I did to improve the read speed: 1. The thing that made the largest difference was make sure to read all of the data in one chunk. Since I was using sqlite3 database as a backing store writing a select statement that selects all of the cache ent...
by alanxz
Tue, 2012-07-17, 17:20
Forum: DCMTK - General
Topic: FileFormat/Dataset read performance
Replies: 6
Views: 7715

Re: FileFormat/Dataset read performance

I guess the first question I wanted answered: is there anything like "Only write out the Dataset in EXS_LittleEndianExplicit because its the fastest to parse"? I'm getting the drift there isn't anything like that. And thats fine - I just wanted to be sure. LZO is pretty quick as far as com...
by alanxz
Tue, 2012-07-17, 14:55
Forum: DCMTK - General
Topic: FileFormat/Dataset read performance
Replies: 6
Views: 7715

Re: FileFormat/Dataset read performance

That was one of my first thoughts: reading a chunk of data from a sqlite3 database, then feeding the whole block in memory to dcmtk: For these bits of DICOM I've removed the Pixel data so the blocks of data are under 128 KB, I usually don't bother break reading the dicom into chunks. The code I'm us...
by alanxz
Mon, 2012-07-16, 20:25
Forum: DCMTK - General
Topic: FileFormat/Dataset read performance
Replies: 6
Views: 7715

FileFormat/Dataset read performance

What can I do to maximize read performance when reading a DICOM FileFormat or Dataset using DCMTK? A bit more detail: I have a situation where we're storing a bunch of DICOM files on disk which are accessed by an interactive program. This interactive program as a part of opening an image, sorts all ...