Image alignment processing times 1.7.3 vs 1.7.4

[Paulo]

Hi all,

with latest release, I again did an image alignment comparison with version 1.7.3 using same 189 image dataset on following system:
 Platform: Windows
 CPU: Intel(R) Core(TM) i7-3630QM CPU @ 2.40GHz (laptop)
 CPU family: 6 model: 58 signature: 306A9h
 RAM: 16.0 GB
 OpenGL Vendor: NVIDIA Corporation
 OpenGL Renderer: GeForce GTX 670MX/PCIe/SSE2
 OpenGL Version: 4.6.0 NVIDIA 425.31

The comparison is shown in following screen capture

Total processing time increases from 24 min 34 sec in v.1.7.3 to 31 min 50 sec in v. 1.7.4, some 30 % increase....
In terms of processing time efficiency, we are certainly not going in the right direction!

[c-r-o-n-o-s]

That's very interesting.

Did you run the tests twice?
Laptops are already quite sensitive to heat and regulate down faster.
Of course, that's probably not the reason...

[Paulo]

cronos, 

I just ran the test once for each version....

following your suggestion, I ran alignment again in v.1.7.4 after a night`s rest and got following processing times:

Matching time   17 min 8 sec
Alignment time   12 min 11 sec
Total time:              29 min 19 sec

So times have diminished a little bit from previous 1.7.4 run but are still significantly higher than v.1.7.3

[Bzuco]

I will gladly test on my sets with locked GPU frequencies, but I don't know where to download previous metashape standard 1.7.3 
You have got less sparse points in 1.7.4, could it be the reason that 1.7.4 is detecting less/more matches on photos and therefore alignment task simply takes different time to complete?

[Paulo]

Bzuco,

actually you have to look at initial Tie Points detected in both runs which is very similar :

132,728 of 387,261  for version 1.7.3 and 119,143 of 388,119 for version 1.7.4.

The final tie pts number (132,728 vs 119,143) depends on the gradual selection done in each case which was tighter for 1.7.3.

PS. if you still have the installer for 1.7.3 on your system, just disinstall 1.7.4, re install 1.7.3 and move it to a different folder. Then re install 1.7.4 again to default folder... You will now have 1.7.4 in default folde and 1.7.3 in a different user defined folder...

[Bzuco]

I am keeping only last ver. of installer  . Maybe I will find some mirror sites with older. ver.
EDIT: Changing "1.7.4" to "1.7.3" in original download link gives me what I need  . I will try tomorrow.

[Bzuco]

Preselect ON: +17% on matching time and +6% on alignment time
Preselect OFF: 0% on matching time and +6% on alignment time