Do you think that enabling rolling shutter compensation with full Txyz and Rxyz parameters might improve the model results, even if it introduces a Z offset?
Next, I will try Smart Oblique (with more images over the same area).
M4T RTK accurate or not ..
- Thread starter Mflyer
- Start date
Next, I will try Smart Oblique (with more images over the same area).
I tried the rolling shutter for the last dataset. It did nothing worth reporting.
My Z offset was within where I would want it. Z is almost always the worse.
The T is not sold by DJI as a mapping solution, and its to me, surprisingly good results are just a bonus. It is my thermal solution that can map with minimal GCPs.
At my real job in public safety we will try:
At my side job at school we will:
My Z offset was within where I would want it. Z is almost always the worse.
The T is not sold by DJI as a mapping solution, and its to me, surprisingly good results are just a bonus. It is my thermal solution that can map with minimal GCPs.
At my real job in public safety we will try:
- Test out the Matrice 4T for accident scene reconstruction. It should work pretty good and will serve as backup to the Mavic 3E. On this use case we are looking for relative accuracy over absolute. But the Mavic 3E has the better camera and will remain the drone we grab first.
- The Mavic 3E will remain our beach mapping solution. I still like its images better than the 4E. The 4E compresses the JPEGs too much. I think this was done for faster uploading into Flight Hub 2. The Mavic 3E still consistently outperforms the 4E in accuracy assessment.
- The 4E will be our 3D modeling solution. The Smart Local 3D mode workflow is quick and creates ultra realistic models. This could be for accident scenes too but will be used for smaller scenes.
At my side job at school we will:
- Try to obtain independent funding to obtain a 4T. All grants now prohibit purchasing DJI drones.
- It can be used for several different classes such as Remote Sensing, Data collection and similar
- Use it both for mapping, 3D models and its thermal abilities
- Use it to teach autonomous flights. There are so many useful flight modes now.
- Use it for teach photovoltaic inspections/roof moisture inspections and maybe even some electrical assessments (We are limited in training props for this)
Thank you for your suggestions. Do you usually use rolling shutter correction with full Txyz and Rxyz parameters when processing data from the Matrice 4T ?
Mapping should be as clean as possible. Software interventions may just give more inaccurate results. This thread showed several 4T outcomes which prove that the 4T is a very capable drone. It all comes down to testing (which I need to do more myself) and finding your workflow to validate results.
Thanks to Jaja6009, we have some good pointers to test out ourself and compare results. To me, absolute X and Y are the ones that matter. Z is always all over the place
I did the Rolling Shutter correction along with using the suggested Adaptive Camera Model per Agisoft's guidance and did not find it to have changed the outcome in any meaningful way worth reporting back to everyone other than to say I tried it and it did drastically change the outcomes.
I am happy with my processing decisions in Agisfot because I ran the data in both Pix4D and Drone Deploy. Both of these solutions have much less user input, so there are less ways to interfere. With both as we saw in the reported RMSE sheet, Pix4D and Drone Deploy were for the most part very similar in results.
Now to find a day to do the final tests. PPK and I will try to use a Local Base for the best possible outcomes.
My poor M4E also needs to get some flight time. I have been flying the 4T nonstop since I got it. The thermal sensor and IR Cut Filter make night flying a blast.
Within your busy schedule.. if you in any way find an opportunity, would you be willing to compare Agisoft numbers to Mipmap? Just curious : )
The M4T in Mip Map
All control points were Check Points.
2 of the points are much worse than the others, but I triple checked, they were marked correctly.
I do not have that extreme error on those points in Agisoft Pro.
The Results are very close though to Agisoft in Total RMSE even though this one fared much better in Z.
MipMap
Agisoft
Interesting results here.
This was RTK. I will do the PPK for the same mission in the future.
It was the school's new baseball field. Again I am in New Jersey and there is not a lot of elevation change, so its limited elevation gain.
RTK Mission
5 Control Points Collected @ 2 minutes each from a base 31 km away. I know too far for RTK.
I made a known point then had the Emlid send corrections to the drone over Local NTRIP. This point was averaged from the 31 km away base for 10 minutes.
All points were used as Check Points.
The M4T was as good as the M4E in almost every test, even beating it using Smart Oblique.
Almost all of my personal tests using the M4E have shown that it is not as accurate as the Mavic 3E we use for beach mapping, hence why I still use the M3E for this purpose. When doing sand volume gain/loss the elevation is the most important aspect with 1 cm of error causing large errors in volume loss/gain.
Unfortunately all of my tests are at long baselines to the base. I am hoping for another test where I have 2 Emlids so that I can just setup on an NGS benchmark nearby and run a test with a very low baseline.
This was RTK. I will do the PPK for the same mission in the future.
It was the school's new baseball field. Again I am in New Jersey and there is not a lot of elevation change, so its limited elevation gain.
RTK Mission
5 Control Points Collected @ 2 minutes each from a base 31 km away. I know too far for RTK.
I made a known point then had the Emlid send corrections to the drone over Local NTRIP. This point was averaged from the 31 km away base for 10 minutes.
All points were used as Check Points.
The M4T was as good as the M4E in almost every test, even beating it using Smart Oblique.
Almost all of my personal tests using the M4E have shown that it is not as accurate as the Mavic 3E we use for beach mapping, hence why I still use the M3E for this purpose. When doing sand volume gain/loss the elevation is the most important aspect with 1 cm of error causing large errors in volume loss/gain.
Unfortunately all of my tests are at long baselines to the base. I am hoping for another test where I have 2 Emlids so that I can just setup on an NGS benchmark nearby and run a test with a very low baseline.
| RMSE US S Ft | RMSE cm | ||||||||
| M4T Nadir Alt Opt | 0.23 | 0.15 | 0.52 | 0.59 | 6.88 | 4.72 | 15.95 | 18.00 | |
| M4T Smart Obl | 0.26 | 0.10 | 0.14 | 0.31 | 7.84 | 2.90 | 4.30 | 9.40 | |
| M4E Nadir Alt Opt | 0.25 | 0.07 | 0.16 | 0.30 | 7.52 | 2.16 | 4.81 | 9.18 | |
| M4E Smart Obl | 0.27 | 0.08 | 0.15 | 0.32 | 8.11 | 2.52 | 4.48 | 9.60 |
Smart Oblique outcome is surprising.
Compared in flight time how much does it differ from trad Nadir? The amount of images would times 3 I guess ..
Compared in flight time how much does it differ from trad Nadir? The amount of images would times 3 I guess ..
