Survey settings with GoPro & gimbal

[Pedals2Paddles]

I haven't been able to find much concise detail on this. And most of what's out there is from before the gimbal even existed. I'm familiar with Tower, creating an auto mission, creating the survey grid, etc. My question is in the detailed settings and what to do with it afterwards.

• Camera is set for GoPro Hero 4 Black Wide in the survey.
• Will it automatically tilt the gimbal down at the start of the survey
• Will it automatically switch from video to photo at the start of the survey?
• What ISO limit should the photo mode be set for?
• Should the GoPro be on 12MP wide or 7MP Medium to remove fisheye?
  
• What speed should I have it fly the survey at? It seems to go rather fast by default.
• What overlap and sidelap numbers should I use? The default is 60/40.
• To get better detail than type Google Earth satellite view, what altitude should it be at?

Is there an existing guide somewhere that details which logs you need to download from the controller and what do with it all afterwards?

 

[ChrisBird]

Is there an existing guide somewhere that details which logs you need to download from the controller and what do with it all afterwards?

Hi Pedals2Paddles,

Look up details on using the geo tagging in MP (Geotagging Images with Mission Planner — Mission Planner documentation), there is some stuff on DIYDrones that is Solo specific. Basically pull the dataflash log from the solo (not the tlog on the controller). Then hit shift-f in MP and then choose the Georef option and then point the tool at the images and the log. Image count must match the number of cam messages in the log otherwise it will fail - obviously you need to get the image to match the relevant cam message.

• Camera is set for GoPro Hero 4 Black Wide in the survey.

The camera setting is just to workout the flight plan based upon the overlap and sidelap, so if you have FOV set to Medium for Pics and have set Wide in the survey it doesnt change the camera (it will stay on Medium).

• Will it automatically tilt the gimbal down at the start of the survey

No it wont tilt the camera down, you have to do that yourself after you take off.

• Will it automatically switch from video to photo at the start of the survey?

If you are recording videoing it will switch to the photo mode every x distance (there is additional delay as it switches back and forth I've been told), so I just put it in photo before take off. I dont need the video footage from those flights.

• What ISO limit should the photo mode be set for?

I set my ISO limit on the photo to 200 (with protune on), havent really tried others (thinking of trying 100 if the GPH4 B supports it). I'm currently playing with filters, cant say any have helped my photogrammetry results.

• Should the GoPro be on 12MP wide or 7MP Medium to remove fisheye?

Depending on the software I'm running it through, so for Pix4D I just use wide as it works. Other software hasnt been as successful (ODM) so I either defisheye the pics or do it in medium FOV but there is still a fisheye effect it just reduced.

• What speed should I have it fly the survey at? It seems to go rather fast by default.

This one caught me off guard my first time doing this with the solo - holy crap it really moves, my other pixhawk drones have a slower speed. I put a 'do speed change' after take off, I've had very good results at 5m/s, I tried it at 7m/s the other day and it resulted in having a leg in the odd pic.

• What overlap and sidelap numbers should I use? The default is 60/40.

I use a 60/60 when on Wide (Pix4D is really good but way pricey). I cant remember what I did on Medium but I think I put it up to 80 for the sidelap.

• To get better detail than type Google Earth satellite view, what altitude should it be at?

I fly at 35m when the surrounding terrain permits (sometimes large trees on hills means that I have to fly higher). Keep the same alt if you can (terrain following is not required). That gives around 1.25cm / pixel (GSD?), some of my flights though have been at 50m and have gotten good results.

Hope it helps.

Chris

 

[Jubalr]

I haven't been able to find much concise detail on this. And most of what's out there is from before the gimbal even existed. I'm familiar with Tower, creating an auto mission, creating the survey grid, etc. My question is in the detailed settings and what to do with it afterwards.

• Camera is set for GoPro Hero 4 Black Wide in the survey. If the GP is stock, yes. If you have an after market lens, you will need to create a new camera profile.
• Will it automatically tilt the gimbal down at the start of the survey. No, tilt it down after takeoff
• Will it automatically switch from video to photo at the start of the survey? Yes, but I switch it to phot when I tilt it down.
• What ISO limit should the photo mode be set for? 400. Less noise is easier on the stitching
• Should the GoPro be on 12MP wide or 7MP Medium to remove fisheye? Fisheye and stitching don't get along, but you need the res to better align images in stitchjing.
  
• What speed should I have it fly the survey at? It seems to go rather fast by default. I use 18-20mph. Default speed is a little fast.
• What overlap and sidelap numbers should I use? The default is 60/40. I use 70/70. Most stitching programs recommend 70 at a minimum
• To get better detail than type Google Earth satellite view, what altitude should it be at?Depends on the mission. Ag missions for NDVI can be flown 300-400. 3D modeling and orthos needed for volumetric measurements need more detail. 150-250' work well. Some Ag missions will also require lower alt, like plant counting.

Is there an existing guide somewhere that details which logs you need to download from the controller and what do with it all afterwards?

• Camera is set for GoPro Hero 4 Black Wide in the survey. If the GP is stock, yes. If you have an after market lens, you will need to create a new camera profile.
• Will it automatically tilt the gimbal down at the start of the survey. No, tilt it down after takeoff
• Will it automatically switch from video to photo at the start of the survey? Yes, but I switch it to phot when I tilt it down.
• What ISO limit should the photo mode be set for? 400 or less. Less noise is easier on the stitching
• Should the GoPro be on 12MP wide or 7MP Medium to remove fisheye? Fisheye and stitching don't get along, but you need the res to better align images in stitchjing.
  
• What speed should I have it fly the survey at? It seems to go rather fast by default. I use 18-20mph. Default speed is a little fast.
• What overlap and sidelap numbers should I use? The default is 60/40. I use 70/70. Most stitching programs recommend 70 at a minimum
• To get better detail than type Google Earth satellite view, what altitude should it be at?Depends on the mission. Ag missions for NDVI can be flown 300-400. 3D modeling and orthos needed for volumetric measurements need more detail. 150-250' work well. Some Ag missions will also require lower alt, like plant counting.
• Is there an existing guide somewhere that details which logs you need to download from the controller and what do with it all afterwards? Yes, most of the sites/programs for stitching have step by step by step guides. I take it by your questions you have not decided on a service/program to process the images?

 

[Pedals2Paddles]

Thanks guys. I didn't look up the WP Nav Speed before trying it out yesterday so I don't know what it was set for. But I think it had to be cruising along at least 20mph. The images came out pretty crappy. I'm going to try again this weekend with a do_set_speed command for 10mph before the survey begins. I'll adjust the image settings as suggested too.

 

[ChrisBird]

Like Jubalr, I should add that I'm about to change my GPH4B lens but I chose the Peau Productions 3.97mm lens should be here on Monday. That way I can process my imagery in a wider range of software without having to defisheye everything. Pix4D is good but it's pricey and I want to use lower cost options.

 

[ChrisBird]

Thanks guys. I didn't look up the WP Nav Speed before trying it out yesterday so I don't know what it was set for. But I think it had to be cruising along at least 20mph. The images came out pretty crappy. I'm going to try again this weekend with a do_set_speed command for 10mph before the survey begins. I'll adjust the image settings as suggested too.

No probs, you'll find that the default is 10m/s from memory so that works out to be 22mph. I've had good results with 5m/s so around 12mph. This is now my favorite part of the hobby, about to start my commercial venture in this space in the next few months. So once you start you'll be hooked!

I forgot to ask are you just stitching or are you doing proper photogrammetry with orthomosaics, point clouds and DSM's?

Good luck with it

 

[Jubalr]

Thanks guys. I didn't look up the WP Nav Speed before trying it out yesterday so I don't know what it was set for. But I think it had to be cruising along at least 20mph. The images came out pretty crappy. I'm going to try again this weekend with a do_set_speed command for 10mph before the survey begins. I'll adjust the image settings as suggested too.

PP, No need to change the WP Nav param. Before starting the survey in tower, tap the screen near HP and make it a change speed WP. That setting is in MPH and will keep that speed through out the mission. try around 15 and see how you like it.

 

[Pedals2Paddles]

Isn't that what I just said? Not changing the parameter, just making a DO_SET_SPEED WP before the survey?

 

[ChrisBird]

Isn't that what I just said? Not changing the parameter, just making a DO_SET_SPEED WP before the survey?

Yes that is it, that is what you said.

 

[Pedals2Paddles]

OK, making sure we're on the same page. Usually I have a takeoff WP, a waypoint or two out the survey area, then the survey, then RTL. I like using speed changes in auto missions. Usually I have it haul ass out to the area, then slow down when reaching the area I care about. So for my next try, I will have it proceed at flank to the survey area, then slow down upon arrival.

 

[Pedals2Paddles]

No probs, you'll find that the default is 10m/s from memory so that works out to be 22mph. I've had good results with 5m/s so around 12mph. This is now my favorite part of the hobby, about to start my commercial venture in this space in the next few months. So once you start you'll be hooked!

I forgot to ask are you just stitching or are you doing proper photogrammetry with orthomosaics, point clouds and DSM's?

I slowed it down to 10mph and 150ft for my next try. That was painfully slow but figured I'll start with that and work my way up faster. I also did a smaller area as a result.

I haven't done anything with the survey images yet. My first run the other day was at the default warp speed and the images were really blurred. I have downloaded Pix4D (15 day trial). It is currently processing. God damn this is a CPU hog!

 

[ChrisBird]

I slowed it down to 10mph and 150ft for my next try. That was painfully slow but figured I'll start with that and work my way up faster. I also did a smaller area as a result.

I haven't done anything with the survey images yet. My first run the other day was at the default warp speed and the images were really blurred. I have downloaded Pix4D (15 day trial). It is currently processing. God damn this is a CPU hog!

I've found 5m/s to be a good stable speed (about 12mph). If you go too much faster and it snaps a pick while its turning you get legs in the pics. Not a big issue as pix4d will filter it out but reduces the accuracy. At 5m/s i can cover a large set of playing fields on a third of a battery.

Pix4d also uses the gpu, turn that option if you can. It will make the processing faster for certain stages. Pix4d produces great results. When my peau productions lens arrives tomorrow I'll be able to try odm and maps made easy with undistorted pics. I use it on my custom birds with canon cams and get good results too.

Good luck.

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