Configure focal length and sensor size


#1

Hi,

If I have two drones with two very different cameras with different size and focal length how can I configure this on drone deploy in order to plan my mission adequately?

Gil


#2

Hi @Gil_Goncalves,

To better help you with this, can you let me know what drones and what mobile devices you are using?

Best,
Hannah


#3

Hi @hannah

I have a phantom 4 pro and in the next week I hope to have a matrice 210.

Thanks.

Gil


#4

Hi @Gil_Goncalves,

When you’re planning your flight our software automatically assumes you are using a Phantom 4 Pro until you connect your drone to DroneDeploy out on the field. The settings should adjust automatically and accordingly if you have “Set Exposure Manually in DJI Go” and “Set Focus Manually in DJI Go” toggled off in your Advanced settings for your flight plan.

Cheers,
Christina


#5

That’s good to know. Does DD also consider the difference in the field of view between drones, as when running a mission I don’t see the gap between waypoints closing up or creating additional ones as a result of running on the Mavic with a narrower field of view.

J.


#6

Hello @James Our platform adjusts for the field of view for overlap. Not to worry! If you want to be sure you can always increase your overlap. Thanks.


#7

What camera are you going to use on the 210?


#8

It was more an observation. I haven’t noticed the width between the waypoints increase having loaded up the mission in the field when connecting the Mavic. Given the Mavic’s narrow FOV, I would have expected at least a couple of additional waypoints beyond the Phantom’s setup on a large map, but instead I don’t see any change.


#9

We are analyzing two possibilities: X4S or X5S. The X4S is for the possibiltie to add a ppk system.

Gil


#10

Personally, I don’t believe you’ll benefit much from using the mighty M210 machine for mapping mission with DD. Firstly, both P4P and X4S cameras are almost identical in resolution and FOV. Narrower lens - say, 25mm - with optional X5S camera on Matrice may not deliver enough oblique data for rendering 3D structural map. This - in turn - may require additional “crosshatch” type flight plans to add extra oblique images for processing. Secondly, P4P is very efficient with battery capacity, where even twin batteries of heavy Matrice 200 series may not compete successfully.

Finally, while Drone Deploy app is pretty well tailored for DJI P4P platform, M200 may create some problems and issues we’re not aware of yet. That said, RTK incarnation of M210 may revolutionize the way we do professional mapping in near future. At this moment, however, with proper flight planning strategy P4P will deliver the best results. IMHO, naturally.


#11

Hi Matthew,

Thanks for the notes. We also intent to use a multispetcral camera on the Matrice 210. I know that the X4S give the same mapping perfomance

as the phantom 4 pro camera. I’ve mentioned the X4S because I want to use a ppk system on the M210, and it seems that for integrating it on a camera it is necessary a global shutter on the camera. The rolling shutter don’t give accurate geotagging!!!

Do you have some mapping experience with the M210? How does he behave in high winds relatively to the P4P?

Regards,

Gil


#12

Gil, I do owe M200 with X5S single camera, and she is taking high winds charmingly, with a noble nonchalance, shall I say. P4P will handle the same wind, but with nervous jerkiness of sort. I’ve made 2 or 3 successful mapping missions with M200 and 12mm lens, but - again - for typical ortho map it seems to be an overkill, equipment value considering. I’m not familiar with requirements for “ppk” system you mention, but are you sure that P4P camera with mechanical shutter will not deliver what you expect? I’ve noticed minor misalignments of stitched map with Google map underlay, but that’s acceptable most of the time. For perfectly true map you’ll need land surveyed reference points (GCPs) to be photographed and processed by DD.


#13

Matthew,

The ppk, as the rtk, is a “geottaging system” but with the diffference that ppk is done in post-processing. Using this system you don’t need GCPs for achieving centimeter level accuracy. We use Photoscan for generationg the orthophotos and Digital Surface Models. DD is only used for flight planning.

Gil


#14

RTK is a global reference only. It is the same base as the onboard module, but with increased accuracy. PPK is referenced by a ground station and by such is tied to the local coordinates which is what the majority of us want. The reason PPK has to be post-processed is because of the latency between the base, the aircraft and the camera fire. The drone industry will catch up with construction GPS tech eventually. I want to pull the drone out of the case, link it to our existing site base that our surveyors and machines are already using and fly. Airgon Loki is the closest I have seen so far.


#15

Excellent question.
I have raised that issue through support in the past as well and was given the same answer. But also observed the same behavior as @JamesC here flightplan’s distance between the legs would not update even though a different drone/lens combo was connected.

Another unexplained thing is regardless of your settings in DJIGO4 for your P4P image ratio (default is 2:3 which is the full sensor), whenever a DD mission starts it switches to 4:3, effectively cropping the image on the sides. Can anyone shed some light on this from DD gurus? What is the reason for cropping the sensor and does overlap calculation takes that into consideration?

Cheers,