Hi tomosa,
On Friday, 3 June 2011 04:42:51 UTC+2, tomosa wrote:
>
> Hello.
>
> I use the Tesseract V3.01 code "tesseract-ocr-read-only".
> According to its ReleaseNotes, it seems to be able to use "Thread-
> safety".
>
> I want to mount the multithread processing at the page level.
> That is, I want to make each thread work for each page at the same
> time.
>
> Now I mount it with OpenMP, but it doesn't operate well.
> Segmentation fault is always generated.
> Where is the place of "Thread-safety" in the source code?
> How can I use "Thread-safety"?
>
> Will you show me your idea if you can use "Thread-safety"?
>
> Thanks.
>
> tomosa
I have exactly the same questions, but I'm using tesseract 3.03 rc1.
I'm trying to use openmp to process one page per thread; so far, I just
modified the ProcessPages code like this:
if (npages > 0) {
pixDestroy(&pix);
//francesco
//modified to use omp:
//define lpage = local page variable to initialize the loop;
//modify branch logic to exclude break statement
#pragma omp parallel for private(pix)
for (int lpage = page; lpage < npages; ++lpage) {
// only use opencl if compiled w/ OpenCL and selected device is opencl
#ifdef USE_OPENCL
if ( od.selectedDeviceIsOpenCL() ) {
pix = od.pixReadTiffCl(filename, lpage);
} else {
#endif
pix = pixReadTiff(filename, lpage);
#ifdef USE_OPENCL
}
#endif
if (pix == NULL) //was break. Now it keeps cycling doing nothing
useful
bool dummy_var = true;
else{
if ((lpage >= 0) && (npages > 1))
tprintf("Page %d of %d\n", lpage + 1, npages);
char page_str[kMaxIntSize];
snprintf(page_str, kMaxIntSize - 1, "%d", lpage);
SetVariable("applybox_page", page_str);
success &= ProcessPage(pix, lpage, filename, retry_config,
timeout_millisec, renderer);
pixDestroy(&pix);
}
//commented out
/* if (tesseract_->tessedit_page_number >= 0 || npages == 1) {
break;
}*/
}
I got segfault too, and debugging via gdb I found the problem here - a
short backtrace follows:
#0 0x00007ffff7829779 in ELIST_ITERATOR::forward (this=0x7fffffffb4d0) at
elst.cpp:237
#1 0x00007ffff7640648 in C_BLOB_IT::forward (this=0x7fffffffb4d0) at
../ccstruct/stepblob.h:28
#2 0x00007ffff776356a in assign_blobs_to_blocks2 (pix=0x83f530,
blocks=0x7fffdc000960,
port_blocks=0x7fffffffb950) at tordmain.cpp:173
Moreover, I tried to run the code under valgrind with the drd tool, and I
got a ton of conflicts.
It seems it really can't be the correct approach, we really need the help
of a staff member here!
f.
--
You received this message because you are subscribed to the Google Groups
"tesseract-ocr" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to [email protected].
To post to this group, send email to [email protected].
Visit this group at http://groups.google.com/group/tesseract-ocr.
To view this discussion on the web visit
https://groups.google.com/d/msgid/tesseract-ocr/ab0d270a-cb89-4288-8280-ecfad3692c31%40googlegroups.com.
For more options, visit https://groups.google.com/d/optout.
