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Can i shot a ruler?
1682 18 2017-5-14
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hyprfrco
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Hello All,

Q: Can you show me a photo of a ruler, taken with your drone camera, flying or static, showing the graduation marks?

For an application seeking for structural inspection at hardly accesible places in buildings, i am needing to see cracks and corrosion details; hence i am more interested in taking photos at 1m or less, rather than panoramic shots. For such i am interested in acquiring a DJI Drone, though i am not decided which i should.

I went to a DJI store last friday, and I asked the sellers for some photo trials with their Phantom 4 Pro drone, under static conditions, and after setting several configurations for the ISO, Shutter, Aperture and White settings, we were unable to obtain a photo in which the rule graduation appear visible. In every photo, the rule graduation appeared blurred, making impossible to use the device for the aforementioned purpose.

Considering the P4 drone features a 4:3, 4860x3648 px camera, leading to a 0.37mm/px resolution estimate by taking photos at less than 1m, in theory the camera should be able to capture the required level of detail -the graduation of a rule-, and also the indicated specs are better than the cameras embedded in standard smartphones -which normally accomplish this objective-.

What we are doing wrong?. Are the DJI cameras indeed unable to take photos of a rule?.

Thank you for your time and aid.

2017-5-14
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Nigel_
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I don't think you can safely fly within 1m of a structure so the answer seems irrelevant...

You want a longer focal length lens so that you can take the image from a safe distance, maybe an Inspire rather than a Phantom?
2017-5-14
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hyprfrco
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Tip: The post by the administrator or moderators shield
2017-5-14
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Eric13
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I would be happy to demonstrate with a ruler to show how good the camera is but can't do it at the moment. I'm sure you would be convinced.

As Nigel put it:
Your problem is a different one.

Shooting indoors you won't have GPS. Flying so close to an object requires the Downward Vision Positioning system working properly. This needs contrast/light and works up to 8 meters only.
Taking photos of dark corners inside a building would also require light on the object.
Ideally this light comes from a side angle and not from some light attached to the drone.

As much as it is challenging to do this with a drone I would recommend to go the old way:
Use a manlift.


2017-5-14
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Labroides
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The Phantom is not suitable for what you want.
It is a camera for aerial photography so it does not focus close.
It has a very wide angle lens which means it makes things look further away.
It is not safe flying within 1 metre of structures, that is just asking for trouble.
If there is any reinforcing steel in the building, that will only make it even more risky.
2017-5-14
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RedHotPoker
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Eric13 Posted at 2017-5-14 13:16
I would be happy to demonstrate with a ruler to show how good the camera is but can't do it at the moment. I'm sure you would be convinced.

As Nigel put it:

With Lume Cubes attached to your drone, you can adjust not only the strength of the light, but also the angle they are directed.
I'm not sure if that would be a benefit to this indoor video cause.

RedHotPoker
2017-5-14
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hyprfrco
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Hello people, glad to receive your comments,

The concern is not if one can or cannot fly the device, or if there are or are not another alternatives. The concern is if we can or cannot "see" the details.

We made a test at a DJI store, and with a P4P we were unable to take a photo of a ruler. That is the point of the question. What is strange given the specs of the camera. We simply were unable to shot a ruler.
2017-5-14
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hyprfrco
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BTW: There are for outdoors walls (i never said indoors), no irregularities, no scaffolding\manlift safe reaching surfaces, in a enclosed space without adverse winds.
2017-5-14
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Mobilcams
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hyprfrco Posted at 2017-5-14 18:24
Hello people, glad to receive your comments,

The concern is not if one can or cannot fly the device, or if there are or are not another alternatives. The concern is if we can or cannot "see" the details.

If you're trying to view it through the go app it will be blurry.
IMG_3231.JPG
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hyprfrco
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Mobilcams Posted at 2017-5-14 18:43
If you're trying to view it through the go app it will be blurry.

How much distance are the rules from the camera?
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hyprfrco Posted at 2017-5-14 19:10
How much distance are the rules from the camera?

Probably around 5 feet.. This picture is zoomed in and cropped quite I bit.. I will post the original picture in a few minutes..
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Geebax
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hyprfrco Posted at 2017-5-14 18:24
Hello people, glad to receive your comments,

The concern is not if one can or cannot fly the device, or if there are or are not another alternatives. The concern is if we can or cannot "see" the details.

I replied to you in one of the many other threads you posted in, the DJI cameras are designed as aerial cameras, they are not suitable for shooting images at the distance you want to shoot at. A number of people have already posted images showing objects shot at short distance, and they are all out of focus.  It does not matter what the DJI specs say, the camera is not suitable.
2017-5-14
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Mobilcams
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I wanted to post the full picture (shrank down in file size for posting) but it is telling me that the file isn't legit?? Wierd..
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Geebax
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Mobilcams Posted at 2017-5-14 20:00
I wanted to post the full picture (shrank down in file size for posting) but it is telling me that the file isn't legit?? Wierd..

Put it up on Dropbox.
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Geebax Posted at 2017-5-14 20:35
Put it up on Dropbox.

Ahh.. Well, I don't use drop box but I use My Drive in Google.. Here is the link Full sized picture here...
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hyprfrco
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Geebax Posted at 2017-5-14 19:35
I replied to you in one of the many other threads you posted in, the DJI cameras are designed as aerial cameras, they are not suitable for shooting images at the distance you want to shoot at. A number of people have already posted images showing objects shot at short distance, and they are all out of focus.  It does not matter what the DJI specs say, the camera is not suitable.

Yes, these drones are made for aerial videos.  Though if the specs and tests are favorable i wouldnt see any constraint for using these equipment.
2017-5-15
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hyprfrco
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Mobilcams Posted at 2017-5-14 20:46
Ahh.. Well, I don't use drop box but I use My Drive in Google.. Here is the link Full sized picture here...

Dear friend, i appreciate your aid. The images are clear, hence the drone are capable for the job we have to do.

I am still concerned why the store people was unable to take a good shot, always blurry. The P4 drone they used was new.

Somebody here could have a picture from a Mavic Pro drone?

Sincerely,
Hyp
2017-5-15
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Nigel_
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hyprfrco Posted at 2017-5-15 08:39
I am still concerned why the store people was unable to take a good shot, always blurry. The P4 drone they used was new.


Because they were trying from within 1m as requested, not closer to 2m.

The Mavic has a longer focal length, but less resolution, I guess it gets about the same detail.


If the aircraft is holding position using GPS which has drifts in accuracy of several meters you will still have a problem safely getting close enough.
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Nigel_ Posted at 2017-5-15 10:51
Because they were trying from within 1m as requested, not closer to 2m.

The Mavic has a longer focal length, but less resolution, I guess it gets about the same detail.

Not to mention I have seen my P4 jump around once because of GPS drift..  I don't know if the GPS system in the sky (not on the drone) was doing a calibration - but it actually moved forcefully about one meter forward very quickly without my input.. I had posted about it in the forums a long time ago - everyone seemed to think that is what caused it..   There are also times where the sun can mess with the signals as well..

What I think could be done about that is to get Lume Cubes and have one pointing down to the ground so that VPS can see the ground (providing you aren't too high up) and one pointing forward to see what you are trying to get a shot of. Remember too - if it is low light,  your shutter is going to be open longer and the drone is constantly moving, this could cause the images to turn out blurry..  You could bump up your ISO - but then you are going to be battling noise, and if shooting JPG - noise reduction which will soften or blur your picture as well.
2017-5-15
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