Sunday, September 15, 2019
ways to increase OpenCV fps
One way to increase the fps of the OCT software might be via multi-threading - using a separate thread to poll the camera as in
https://www.pyimagesearch.com/2015/12/21/increasing-webcam-fps-with-python-and-opencv/
Another way might be the cufft library?
https://www.researchgate.net/post/How_efficient_are_the_parallel_2D_FFT_implementations
Saturday, September 14, 2019
tutorial on 360 to dome with Vuo on Mac
In the second half of this tutorial, Paul talks about warping 360 videos to dome -http://paulbourke.net/dome/vuo/
Edit: Can now use OCVWarp and do this ...
Thursday, September 12, 2019
system program problem
Popup on startup - System Program Problem detected. The solution was to clear /var/crash as per this post.
Saturday, September 07, 2019
increasing font size in Octave legend
Some figures created in Octave had very small font sizes when added to the LaTEX manuscript. Trying to fix the text with Inkscape led to kerning issues similar to this post. So, found these solutions at
https://stackoverflow.com/questions/1532355/increase-font-size-in-octave-legend
Used commands like
print ("j0exp.eps", "-depsc", "-F:20")
Tuesday, September 03, 2019
starting offline processing in a new thread - C++
Tried various options to begin processing in a new thread for BscanFFT, without locking the UI -
Just
std::system(offlinetoolpath);
// - this causes the BscanFFT program to wait for the offline tool to finish
Then,
pid = fork();
if (pid == 0)
{
// child process
std::system(offlinetoolpath);
}
else if (pid > 0)
{
// parent process
}
gives the error
[xcb] Unknown sequence number while processing queue
[xcb] Most likely this is a multi-threaded client and XInitThreads has not been called
[xcb] Aborting, sorry about that.
BscanFFTspinj.bin: ../../src/xcb_io.c:259: poll_for_event: Assertion `!xcb_xlib_threads_sequence_lost' failed.
Apparently, system specific is safer, http://www.cplusplus.com/forum/beginner/13886/
"Actually, the most important disadvantage of system() is that it introduces security vulnerabilities. Using a system-dependent method (that skips the shell) is always safer.
In Windows, it is CreateProcess(), which is really straight-forward to use.
In POSIX (Linux, etc) it is a combination of fork() and one of the exec() functions.
http://linux.die.net/man/2/fork
http://linux.die.net/man/2/execve
http://linux.die.net/man/3/execv
These are also easy to use, but there are some caveats. Follow the example codes."
execve with the example code gave
(show:9323): Gtk-WARNING **: 10:47:16.601: cannot open display:
suggested using execv instead. This worked.
external hard disk prices
The 3TB drives seem to be attractively priced due to the sharp drop in per TB price as compared to 2TB drives.
Monday, September 02, 2019
gimp 16-bit caution
On Linux,
file filename.png
gives information about the file, like bit-depth and so on.