Phantom 4 image problems

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Hi I am using my phantom 4 for field mapping but it has developed a dark area in the centre of every image which when processed together causes dark striping on the maps directly below the drones flight path.
I have used DroneDeploy, precision mapper and gs pro and all have the same dark centre area. I have been using the auto settings on all these apps. I asked DroneDeploy to check the images and they suspected a hardware problem. I have sent some images to DJI for analysis and thought someone on here might be able to offer help on the matter please.
The drone usually flies at 100m with a 75% forward and a 65% side overlap.
7c5737e57f825ab71ea9f75c440f46c5.jpg
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Are you using any filters on the drone, like the PolarPro, or is it the original P4 lens?

I would say it's actually not a hardware issue at all but just stray sunlight refracting on the sensor.

What would help would be a 'Lens Hood' like you'd see on a DSLR or Camcorder but I don't think any exist for the P4.
 
Hi thanks for reply, no not got any filters on just the standard P4 lens.

Its strange as when using for photography i dont see any darker areas in centre.

Perhaps a filter for the mapping might work, hoping to find someone with same drone doing the same job to get a comparison.
 
Ok.

Unless the overlap of 65% is causing it to darken up, perhaps?

Could you space the overlap out more?
However, to really troubleshoot it, you'd need the same light conditions as experienced on the day the photos above were taken as well as sun direction which is obviously hard to achieve.

Also, can you try taking it out of Auto and adjusting your ISO and Shutter Speed yourself. Select D-Log and then try adjusting the contrast & colour in the app or on your PC etc?
The colour correction may come up more uniform.
 
Is this effect only noticeable on fields? If so, it could be related to the directionality of the vegetation (vertical) so that it really does appear darker when viewed from directly overhead - i.e. it could be real. Have you tried testing with images of uniformly illuminated flat surfaces?
 
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Is this effect only noticeable on fields? If so, it could be related to the directionality of the vegetation (vertical) so that it really does appear darker when viewed from directly overhead - i.e. it could be real. Have you tried testing with images of uniformly illuminated flat surfaces?
I thought it could be the actual field as well. If you look at the lines running vertical in the photos they appear to have uniform color and lighting running their length with no darkening light in the green areas.
 
Is this effect only noticeable on fields? If so, it could be related to the directionality of the vegetation (vertical) so that it really does appear darker when viewed from directly overhead - i.e. it could be real. Have you tried testing with images of uniformly illuminated flat surfaces?
I also think it's like sar104 describes.
 
Hi thanks I think you are correct somehow the canopy thickness of crop, direction of sun/light etc is the cause. However DJI has come to the conclusion the it's a camera fault and I should send it in to be checked (it's under warranty still). I will have a play with manual settings when out next time. Would a filter help eliminate any of this and if so what strength.
 
Hi thanks I think you are correct somehow the canopy thickness of crop, direction of sun/light etc is the cause. However DJI has come to the conclusion the it's a camera fault and I should send it in to be checked (it's under warranty still). I will have a play with manual settings when out next time. Would a filter help eliminate any of this and if so what strength.

If that hypothesis is correct then filtering is not going to help - it is a real variation in reflected light as a function of viewing angle relative to the crop stalks. The only thing that you could do is implement some custom post processing to even out the apparent brightness.

If the camera does not display that effect with a uniformly illuminated flat surface, then it is not the camera and I would not bother to send it back.
 
I have now done some fields on manual settings and the images do look better so will monitor it for a while and won't send it back yet. Many thanks for your replies of help.
 

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