What causes the warning "very high apparent capture speed"?

Contributing and equipment Command line tools
1

I processed two videos about an hour long which involve some Autobahn driving, about 75km, 1 hour each way.

I sampled the videos with the mapillary tools (--video_sample_interval 1.5), geo-located the images with JOSM with a GPX file I recorded separately. Then cleaned up a bunch of files (like waiting at stop signs, lights). Now the next step I usually do is fix the orientation:

mapillary_tools process --advanced --import_path "images/" --user_name user --interpolate_directions

This triggered the following warning for both sequences:

Warning: The distance in sequence including images
C:.…\20190807-v-ms_000016.jpg
to
C:.…\20190807-v-ms_002548.jpg
is too large for the time difference (very high apparent capture speed). Are you sure timestamps and locations are correct?

What is the cause of this message? Is it movement speed, amount of images?

When I open the files in JOSM, on a map, they look alright.

2

Well, I guess I figured it out:

Warning appears if the tool detects a GPS speed of over 45m/s (162kph, 100mph) I’ll upload my sequence and report back how it went

1 Like
3

same here,
First thought was that they have recently changed something in the mapillary_tools
But the version is still the same 0.5.0

Before I have never seen such a warning (I am also driving highways, long sequences, 300-1300 km) with ~100-110 kmh average speed

I have got this warning when I was processing my last 1300km journey from Warsaw to Moscow.
3 out of 6 sequences returned a warning.
I have rechecked everything and have not noticed any issues with data/tags/gps.

Good thing is that this does not have any impact on the result, so it’s just a warning which you can ignore (if you are sure that you did it right).

4

I am not an expert in the python scripts…
GPS speed over 162kph - from GPS track, or calculated by tools?

My average speed was well below, could be 120kph, not more.
Max speed on my recent journey was 140 kph (speedometer), so below 162kph for sure
GPS-receiver could return erroneous speed data sometimes (when passing areas without GPS signal)

And still - I have got this warning on 3 sequences

5

Calculated from the coordinates and timestamps in the image EXIF data. In my case I may indeed have hit that limit.

6

well, maybe I misunderstood the logic, but I guess it is normal that MAX_SPEED is above AVERAGE CALCULATED SPEED

If I read the script correctly, the warning is returned if AVERAGE CALCULATED speed is above MAX SPEED detected by GPS.
And this should not really happen, average speed cannot exceed MAX speed… so I wonder what makes the calculation wrong…