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Jul 04, 2019, 03:17 PM
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Adventures with a robot mounted gopro 7


Stabilized gopro 7:

Gopro 7 60fps footage (13 min 50 sec)


Gopro 7 stabilization comparison (5 min 37 sec)


Tempo run with gopro 7 stabilization (20 min 52 sec)


Unstabilized gopro 4:

Embarcadero intervals (18 min 37 sec)


Tempo run (22 min 55 sec)


There's no contest between today's in-camera stabilization & the software stabilization lions lived with for the last 20 years.

The lion kingdom went with the gopro instead of the DJI because of the color & the wider field of view. Lions can barely see anything on the rear screen, let alone the postage stamp front screen of the DJI, so that wasn't a plus.


Based on a more complete picture of the features from Rainmaker Guy & the limited teardown information, the gopro7 is the same as the 6 except for the DDR being doubled. Doubling the DDR was the key to improving the stabilization.


The stabilization sauce is implemented in Japan by socionext.com. The 2 key innovations in the last 5 years are read ahead stabilization & rolling shutter correction. Lions lived in a time when the 1st single chip encoder for H.264 came out, just 13 years ago. It was a stretch just to encode 720p on a single chip. It took 2 chips to encode 1080p.

Today, the Socionext SC2000 encodes 4k 60fps in H.265 while also doing read ahead stabilization, rolling shutter correction, & camera stitching. It was only a year ago that lions still had a computer with 2GB of DDR taking up a stick on a motherboard.

All the image stabilization is driven by an IMU with a samplerate of 6400Hz. The fastest lions used in quad copters years ago was 1khz. At 6400Hz, they get 106 readings in each frame. It can easily detect changes in motion at different points in the scanning of the sensor. The memories of jello are gone. If only DSLR's implemented rolling shutter correction with gyros.


The key to stabilization was pioneered at Google for stabilizing gootube videos. They realized buffering several seconds of video into the future allowed the algorithm to anticipate future motion out of the sensor area. The algorithm could begin panning the video projection sooner rather than after motion was already out of bounds, giving much smoother results. The same thing is done for limiting audio loudness, but here it's done with video.


The effect of read ahead stabilization is quite dramatic, with no significant increase in sensor size.
Last edited by Jack Crossfire; Jul 04, 2019 at 03:25 PM.
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