Reality Capture for Traffic Crash Reconstruction

Development Asset Creation
,
1

Greetings,

I’ve recently been exploring Reality Capture as an alternative to Pix4D for investigating traffic crashes. I really like Reality Capture thus far, especially the pay as you go pricing model which is nice for the public sector where funding can be difficult to come by.

My first hurdle I’ve come across is the size of the exported ortho.

What I have is a scene that was flown with a drone and processed (73 photos). The drone has consumer grade GPS so after processing I imported RTK GNSS points from my area’s local correction network and mapped 6 of those as GCPs. The additional 70-something RTK points serve as markers for roadway evidence and layout - they dropped into the scene nice and accurate. I actually find the ease of the GCP editor in RC to be easier to use than the one in Pix4D. I then turned off the GPS from the drone photos and reprocessed with the GCPs. My scene was then clipped and trimmed into a nice rectangle that is around 100ft x 600ft. I exported an ortho and the .tiff came out over 4gb. I found some settings and was able to get it down to around 1.9gb.

Is there a way to get this file smaller? Previous outputs from Pix4D for a similar sized scene would probably be under 200mb. CAD programs don’t like that large of a .tiff so it creates problems on the “next step.”

Thanks,
Dan

2

Hi Dan,
for the smaller export try to use smaller resolution during ortho creation or various format.

3

When you say adjust the export resolution do you mean the ortho pixel size? I noticed that if you use “estimate” it creates a very large height x width and was giving “units per column” in the 0.00x ft per pixel… way more resolution than needed for my purpose. By adjusting that to a range of 0.04 - 0.05 I have been getting much more manageable export file sizes.

4

Yes, I meant that. Also, by smaller resolution I mean bigger pixel.