Projector-Camera Calibration - the "easy" way

First let me open by saying projector-camera calibration is NOT EASY. But it's technically not complicated too.

It is however, an amalgamation of optimizations that accrue and accumulate error with each step, so that the end product is not far from a random guess.
So 3D reconstructions I was able to get from my calibrated pro-cam were just a distorted mess of points.

Nevertheless, here come the deets.
Continue reading "Projector-Camera Calibration - the "easy" way"

Share

Android Camera2 Touch-to-Focus

Man Camera2 APIs are hard to master...

I've scanned SO for a way to get touch-to-focus to work on Android and could not find a solution that works.
These were very partial, or provided only scaffold code which I couldn't use:

Finally I was able to do it by myself this way:

Enjoy
Roy

Share

[Python] OpenCV capturing from a v4l2 device

I tried to set the capture format on a webcam from OpenCV's cv2.VideoCapture and ran into a problem: it's using the wrong IOCTL command.
So I used python-v4l2capture to get images from the device, which allows more control.
Here is the gist:

Enjoy!
Roy

Share

Extending the hand tracker with snakes and optimizations [w/ code, OpenCV]

I wish to report of a number of tweaks and additions to the hand silhouette tracker I posted a while back. First is the ability for it to "snap" to the object using a simple Active Snake method, another is a more advanced resampling technique (the older tracker always resampled after every frame), and of a number of optimizations to increase the speed (tracker now runs at real-time on a single core).
Continue reading "Extending the hand tracker with snakes and optimizations [w/ code, OpenCV]"

Share

FFMPEG video writer - now with animated GIF support [w/ code]

rect3825So animated gifs are awesome if you're writing a software blog. It saves all this time working with YouTube embeddings and stuff, and your "videos" are stored locally. The simplified FFMPEG writer was before unable to output animated GIFs, but I've tweaked it and now it does. It's also a nice piece of code to learn how to FFMPEG in C.
Continue reading "FFMPEG video writer - now with animated GIF support [w/ code]"

Share