OK, for more reasons than one I processed the last sequence I created with my “roof rack”.
It’s a two suction-cup system. I used the car antenna to secure the rig (if the cups would fail…). The whole thing stayed put, even with the accident I had, so I expect it’ll hold on the highway as well
I set the recording to max resolution and max frame rate (25 fps)
I did have a bit of work improving my Perl script to get the matching right with the GPX track. I discovered a few optimizations to the microsecond calculation, since I now have 25 images per second in stead of the previous test of 1 image per second.
Furthermore I improved the script to exclude images that are les then 1.5 meters away of the previous image. This resulted in an distance ranging 1.5 and 2.3 meters, which in my opinion is more then enough. It reduced the sequence from 4.235 to 1.269 images.
Also I discovered that using a faster moving vehicle doesn’t improve the quality of the GPX track. It is best to drive as slowly as legally allowed to get the best possible GPX track. And seriously slow down at turns to give the GPS a chance to discover and record the change. I had to manually adjust the sequence at one sharp turn. Beside that the interpolation went perfectly and It worked good enough to use a start time and increment 1/25 th of a second each image.
This 4 minute track resulted in a MP4 file of 13,5 Gb. The raw unstitched datafile is almost 4Gb and the separate JPG files are a bit over 14Gb (in the best ffmpeg quality I could export them). So it’s about 1 Gb per minute raw recording resulting in a MP4 for processing of 3.3 Gb per minute. So I could drive around for a bit over an hour to get a raw file that fits my 128 Gb micro SD card… Then I’dd have a 400 Gb MP4 for processing… Also to generate that 13.5 Gb file it needed two hours of stitching on my computer… So really large tracks likely aren’t that good of an idea
I had done several more tests, but I didn’t like the GPS quality and also I think I need to extend the distance between the camera and the car. I have published this one sequence to see how it comes out, but I think I need to buy a lightweight “extension stick” to see less car in the images.
When the track is online I’ll publish a link.
[update] here it is:
I’m sure I set the orientation correctly in my Perl program, what happend? One image is correct, the next looks the other way etc!?
[update]
Must need a bit of time, all looks well now
What I feared, to much car in view, how much higher would i need to go to get it decent?
[update]
Now that the sequence is correctly orientated, it’s easier to evaluate:
I think it looks as well as the “walking sequence” so faster motion doesn’t influence the image quality. How much higher would be ok though? Higher is better naturaly, but to high is a danger to stability and the risk of to much stress on the suction cups…I’ve ordered this: