Experimental studies of the GoPro Max camera revealed a somewhat surprising result: horizon leveling in 360 Time Lapse Photo mode works, but partially.
Let’s put everything in its order. The initial conditions are as follow:
- GoPro Max camera
- Latest release: MAX Update v1.50 | May 6, 2020
- Room info: H19.03.01.50.00
- GoPro App version: 6.18 (9351)
According to the official information of the manufacturer about the camera firmware update from May 6, 2020, it is stated that the horizon leveling capability has been extended from the HERO mode to the HERO TimeWarp and Photo modes. The 360 Time Lapse Photo mode is not specified in this list.
Among the key requirements of our project is the use of interval photography with horizon leveling. Due to the lack of horizon leveling in this camera, we have adapted an open source algorithm to solve this issue (https://bit.ly/30VRMzS).
To capture the camera’s tilt angles, the AndroSensor mobile application was used, which can shoot and record in the background in the CSV format the necessary orientation angles of the mobile phone, namely: azimuth, roll and pitch.
To be able to assess visually horizon leveling of spherical panoramic images in the equirectangular projection the experiment was conducted in a room with plenty of strictly vertical lines (corners of walls, furniture, etc.).
Before the start of shooting, the clock of the mobile phone and the camera were synchronized (for this, the GoPro App has a Set date and time button ).
The experiment consisted of (almost) simultaneous launch of the camera in the 360 Time Lapse Photo mode and the inclinometer with subsequent movement around the room and sporadic change of tilt angles (roll and pitch) in the range of approximately ± 30-40°. The images and recordings of the inclinometer were taken on a computer, where the procedure of adjustment (rotation) of the images to the angles of inclination recorded by the inclinometer took place.
The first results were embarrassing and surprising at the same time - the adjustment did not work. The reasons were not clear.
In additional research, we tried to adjust the original images using Hugin software and at the same time to get the values of the angles needed to make horizon of these images leveled.
The result was also unexpected.
The strange thing is that the pitch obtained manually (by Hugin software), although with errors, but correlates with the values measured by the inclinometer (bottom graph). At the same time, the roll somehow stays close to zero.
A couple of days of reflection led to the assumption (hypothesis) that the roll may already be leveled (stabilized). Then this would explain our observation.
Based on this, a simple experiment was performed: launching the camera in the 360 Time Lapse Photo mode without the inclinometer with changing of only one angle of the camera - roll. And, surprisingly, the result confirmed the hypothesis - all images remained with horizon stabilized.
This gives the impression that the manufacturer has made the horizon leveling for the 360 Time Lapse Photo mode “by half”, and, therefore, we can expect the next firmware update with 100% horizon leveling for this mode soon.
The original text in Ukrainian including pictures is here https://bit.ly/2Qa17xq.