Aerial images for ortho-mosaics, camera settings and more

I'm about to make a first try of an ortho-mosaic aerial image of an area about 600m x 600m.

I plan a forward overlap of about 80% and a sidelap of about 60%.
Does that sound reasonable?

Which shutter speed is appropriate for AGL=150m, v=10m/s, f=20mm?

The area I'm about to map is not totally level, AMSL is between 500m and 580m.
For optimal post-processing, shall I aim at constant AGL or constant AMSL?

I also appreciate any other beginner's hint(-s).

You need to be a member of diydrones to add comments!

Join diydrones

Email me when people reply –

Replies

  • Thanks a lot for the valuable input.

  • Constant AMSL (waypoints will be set this way by default)

    Anything above 1/1250 is very safe, take a picture on the ground to make sure it's not requiring a very high ISO though. If you get ISO 100 at 1/1250 then you'll be in good shape.

  • Reto,

    I'm not want to discourage you about doing AP (aerial photography), but many other parameters must be taken into account; after all you got to synchronize two systems: plane-APM and a camera and each one has many variables. Since you are going to take a picture, distance from camera to object is crucial (meaning here UAV altitude). Ideally you should keep same altitude AMSL through the trip so as to keep the images representing the same magnification level under the same resolution set; otherwise closer objets (mountains) will look smaller than they are and edges of the pictures will not match each other during processing. If you are going to do this by trial-error till you get an acceptable result is fine to test several setting at several flights, but I do not recommend you such way because the possible combinations of parameters is huge!. You can google some basic AP calculators for this; some of them are based on specific commercial camera models like Sony NX5, other calculators are more generic but more inaccurate. Concerning your overlaping, a forward 60% linelap and 20-25% sidelap is fine. Keep in mind what seems obvious in regular photography: the farther (elevated) the camera, the bigger the landscape captured but the lower the resolution obtained; the faster (speedy) it goes, the more frequent the shooting pace must be to keep overlapping among pictures. Likewise, as more elevated it goes, the faster it must move because it capture more lanscape every shot (supposing shooting pace remains the same). Untill here the relaxed way. But if you really want to understand and predict your settings and hence results with some accuracy before burning tons of batttery mah, I recommened you for starters to read some about photography (focal distances, field of view -FOV-, camera film, CMOS and CCD sensors, understanding pixel resolution and true pixels), then identify what type of sensor and resolution your camera does boast as to understand a bit better the tool you get. Then jump back to some googled AP calculators and you will understand better what parameters are asking for, or if you are more geek or math leaned, tailor by yourself in excel or mathlab your own calculator as I did my current one. Last hint: before expending those bugs burning your pocket in specialized software either on-line or installed, make a couple of rehersals with your pictures by using a google earth print-screen image of your target site as guiding background and overlaping 15-25 stills by photoshop or any cheap image editor allowing layers: in one hour you will see whether last settings worked out or not before swimming with GPS tagged images processing.

This reply was deleted.

Activity

DIY Robocars via Twitter
RT @a1k0n: Did I get rid of hand-tuned parameters? Yes. Am I still hand-tuning more parameters? Also yes. I have a few knobs to address the…
yesterday
DIY Robocars via Twitter
RT @a1k0n: I'm not going to spoil it, but (after charging the battery) this works way better than it has any right to. The car is now faste…
yesterday
DIY Robocars via Twitter
RT @a1k0n: Decided to just see what happens if I run the sim-trained neural net on the car, with some safety rails around max throttle slew…
Monday
DIY Robocars via Twitter
Saturday
DIY Robocars via Twitter
RT @SmallpixelCar: @a1k0n @diyrobocars I learned from this. This is my speed profile. Looks like I am too conservative on the right side of…
Saturday
DIY Robocars via Twitter
RT @a1k0n: @SmallpixelCar @diyrobocars Dot color is speed; brighter is faster. Yeah, it has less room to explore in the tighter part, and t…
Saturday
DIY Robocars via Twitter
RT @a1k0n: I'm gonna try to do proper offline reinforcement learning for @diyrobocars and throw away all my manual parameter tuning for the…
Friday
DIY Robocars via Twitter
RT @circuitlaunch: DIY Robocars & Brazilian BBQ - Sat 10/1. Our track combines hairpin curves with an intersection for max danger. Take tha…
Sep 22
DIY Robocars via Twitter
RT @SmallpixelCar: Had an great test today on @RAMS_RC_Club track. However the car starts to drift at 40mph. Some experts recommended to ch…
Sep 11
DIY Robocars via Twitter
RT @gclue_akira: 世界最速 チームtamiyaのaiカー https://t.co/1Qq2zOeftG
Sep 10
DIY Robocars via Twitter
RT @DanielChiaJH: Always a good time working on my @diyrobocars car at @circuitlaunch. Still got some work to do if I’m to beat @a1k0n howe…
Sep 10
DIY Robocars via Twitter
RT @SmallpixelCar: My new speed profile for @RAMS_RC_Club track https://t.co/RtLb7TcgIJ
Sep 10
DIY Robocars via Twitter
RT @SmallpixelCar: Practiced at @RAMS_RC_Club today with my new @ARRMARC car https://t.co/AEu2hCx89T
Aug 28
DIY Robocars via Twitter
Aug 24
DIY Robocars via Twitter
RT @gclue_akira: 柏の葉で走行させてるjetracerの中身 #instantNeRF #jetracer https://t.co/giVvuE4hP7
Jul 4
DIY Robocars via Twitter
Cool web-based self-driving simulator. Click save when the AI does the right thing https://github.com/pncsoares/self-driving-car
Jul 4
More…