Monthly Archives: April 2012

MATLAB data cursor–higher precision (more digits displayed)

MATLAB data cursor by default gives you 4 digits of precision. You can increase the precision of MATLAB’s data cursor (displaying more digits) by altering the “default_getDatatipText.m”. Look inside “default_getDatatipText.m” for this: function [str] = local_Geometry_getDatatipText(hgObject,hDataCursor) % Determine datatip string that appears for a patch, surface, or line DEFAULT_DIGITS = 4; % Display 4 digits […]

Converting RIS citations to Bibtex / Biblatex citations

the handy utilities at: will convert RIS to Bibtex (Biblatex) format. You must compile from the source code (no problem). Here’s how: Download most recent copy from: Extract to /tmp directory type cd /tmp/bibutils* type ./configure && make && sudo make install Now, to convert from RIS to BIBTEX, imagine i have cit02.ris, […]

GIMP Greek characters Ubuntu

Here’s how to enter Greek characters in GIMP (or likely many other Ubuntu/Linux programs) See the chart at: the row labels e.g. 03bx are the first 3 characters you type after the ctrl+shift you will see below. The last “x” value is the column of the table To enter the characters, first press and […]

Hecht “Optics” 4th ed. Errata

The quite useful “Optics” text by E. Hecht like all texts has a few errors that have been pointed out by Chris Mack at:

Cropping AVI files in FFMPEG

The syntax to crop AVI files in FFMPEG has changed recently from the previous syntax. The syntax for FFMPEG version 0.7.3 AVI cropping is as follows: ffmpeg -i input.avi -vf crop=439:455:73:15 -vcodec mjpeg -qscale 2 output.avi The assumptions made above were that you wanted your output video to be: 439 pixels wide 455 pixels high […]

Matlab R2012a Linux Computer Vision Toolbox bug

The vision.VideoFileReader method will issue a “Could not open the specified file” error if you use the ~ in the filename for your home directory. The ~ notation works for every other Matlab command but vision.VideoFileReader e.g. non-working code filename = ‘~/myVideos/foo.avi’; hvfr = vision.VideoFileReader(filename, ‘ImageColorSpace’, ‘Intensity’); step(hvfr) >>Error using VideoFileReader/step Could not open the […]

LabVIEW 2011 64-bit (on Windows 7 x64) installation

LabVIEW 2011 has only a few toolkits that work as a 64-bit installation on 64-bit Windows 7. You can see the list of the supported LabVIEW 64-bit toolkits at: With regard to Device Drivers, the same Device Drivers DVD or download (4.8GB) is used for 32-bit and 64-bit LabVIEW. When you start the Device […]

LabVIEW 2011 Device Drivers installation (unzipping) issues

The built-in ZIP-file decompression of Windows 7 x64 does not seem to be able to handle the 4.8GB download of the LabVIEW 2011 Device Drivers–the ZIP decompression crashes after several minutes. I have found that the free, open-source (FOSS) 7-Zip program handles such large (>2.1GB) ZIP files easily, unzipping this large 4.8GB file in about […]

MATLAB Linux AVI playback “only uncompressed AVI movies can be read on UNIX” error

MATLAB on Linux claims to only playback uncompressed AVI files on “UNIX” systems. However, MATLAB on Linux can’t even play all uncompressed AVI filed depending on your particular system configuration with gstreamer. The solution thus far, with MATLAB 2012a, seems to be using Motion JPEG in AVI videos. Here’s a tentative solution for playing back […]

MATLAB R2012a (student version) in Ubuntu 11.10 (64-bit)

The student version (32-bit) of MATLAB R2012a under Ubuntu 11.10 64-bit seems to work just fine. With R2011a student version, I had issues with the Symbolic Toolbox not working, i.e. using 100% CPU and needing to use “xkill” to stop MATLAB. No such issues with R2012a student version, thankfully. Provided that you chose to install […]