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Messages - cadm8

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61
A question regarding terrestrial photos... We have a set of aerial photos that align easily and some ground photos (same place) from a number of different locations that do not align by any setting available (even between them). Is there a way to insert manual tie points for the ground photos and then align them with the aerial ones?

62
P.S. About cadm8 post: How do you set white balance so ?
Depends on the software you're using... With Ultimate flight there is a setting within the manual parameters, same is for DJI GO

63
My small addition to all the above great posts is to set the white balance and not use auto, so you don't get pictures with different colors

64
Actually we're using a P3P, so the P4P sensor etc is a big improvement, but you have to consider what the reality is and that it is not true 20MP...

65
handling survey with our Phantom 4 Pro (Really nice camera by the way).

check this first:
http://www.phantompilots.com/threads/p4p-image-not-true-20mp.111480/

66
Regarding your speed, I would say it's OK, maybe a little slow? I'm not sure though about the flight height, I think it is way too low for such type of work. Do you need the over-detail you're getting?

Really, I cannot comment something more about the 0 point limit, maybe someone other might have an idea. We currently use 40k/10k and it achieves alignment even with the majority of oblique imagery

67
I haven't yet read Jan's paper (but I will), what I would ask is what is your flight speed? I've ran some tests in a sort of "test field" and things get a little difficult for the P3P at speeds above 8-9m/s up until 10-15 m/s (as the https://www.google.gr/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&cad=rja&uact=8&ved=0ahUKEwjG2uyJh-HTAhUPEVAKHa89BG4QFggtMAE&url=https%3A%2F%2Fpix4d.com%2Fwp-content%2Fuploads%2F2016%2F05%2Fpix4d-isprs-paper-rolling-shutter-final-edited.pdf&usg=AFQjCNEF6qH4VszC1bLCSSCYwJiy4EyCeg&sig2=uZA_6AbOrKzKWG_GoW9Y3g Pix4D paper suggets too)

Regarding my experience with the correction model, I'm getting algorithm wise, a 3-4 times (easily) increased accuracy, especially in a recent project where we surveyed buildings with the total station too, we can reproduce previous accuracies (4-5cm) and maybe half that. Though hadn't had the chance (nor will, we don't own a laser scanner!) to run a similar test as yours

PS: is there some reason why your tie point limit is 0?

68
General / Re: DJI Phantom 3 and 4 Camera calibration parameters
« on: April 06, 2017, 11:16:22 AM »
I have to note that I had used Photoscan earlier without any photogrammetric background (just surveying background) and the final product has been exceptional. More now with the rolling shutter correction, aerotriangulation gives you unbelievable results!!

69
General / Re: GSD and GCP in very steep terrains
« on: March 10, 2017, 03:44:14 PM »
With UltimateFlight you can just draw paths on tablet screen but is not so good to plan a photogrammetry mission...
No, actually it is the only reliable and versatile software available. You can draw your paths in CAD or other software and import CSVs with full info ie altitude, speed, photo intervals etc and even drone headings. Check out their google group also...
http://djiultimateflight.com/

70
General / Re: GSD and GCP in very steep terrains
« on: March 08, 2017, 01:51:04 AM »
Good thing to have designed it yourself! Actually you can use also "Ultimate flight", it has the ability to load waypoints with varying altitudes and also preload DTMs. Regarding your project, I have had success with scenario A in a relevant project concerning a steep faced quarry https://skfb.ly/YRPn

All went well and it was fantastic for the Phantom3 to be climbing the steep paths we designed!

71
General / Re: Fly Through
« on: February 10, 2017, 06:03:58 PM »
You can also try Global mapper
https://www.youtube.com/watch?v=t4jaWwC53zA

72
General / Re: Recommendations for high speed calculations
« on: November 29, 2016, 04:15:04 PM »
My current server is XEON E-52683 v4, 256 GB RAM, GeForce GTX Titan X and everything is running super fast

 8) :o

73
General / Re: Agisoft PhotoScan 1.3.0 pre-release
« on: November 29, 2016, 11:50:57 AM »
I don't know if this has been proposed, but I think it would be helpful to be able to create multiple point clouds within the same chunk. That would help in cases where you would like to reproduce certain areas of a project in high accuracy while others in lower accuracies (ie ground data)

74
Hello, there is a published paper https://pix4d.com/wp-content/uploads/2016/05/pix4d-isprs-paper-rolling-shutter-final-edited.pdf that actually states that the RS effect from an Inspire with a FC300X camera, ie close to that of the Phantom 3, only with slightly narrower FOV, is about 3-5cm greater when their RS compensation algorithm is not being used. What are your thoughts, could you minimize the effect by going slower at about 3-5m/s?

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