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Author Topic: Can photoscan & Metashape work with stills from 4K camcorder slowly panned ?  (Read 2689 times)

Steve003

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Hi,
a camera takes a still image perfect if shutter greater than focal length.
A camcorder when panning  is a different thing, must the stills be as perfect for photoscan or Metashape to work.
Would a 4K camcorder save taking loads of photos, would we have to extract the stills or can Agisoft work with video ?

detail of what I tried...Using an AX100E 4K camcorder by Sony, panning can look a bit jittery, even very slow panning, using 1/50 second 0db f6.8 0density filter, lighting dictated this if using 0Db gain, would a faster a shutter speed help ? but then the depth of field would suffer, or would it, are f numbers a different thing on camcorders ? It was held on wide angle throughout the sequences.

Steve

Kiesel

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Hi Steve003,

look at File/Import/Import Video......and at page 17 of the manual.

I don't have used it, so no experience I can share, sorry.

Regards

Kiesel

Steve003

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Hi Kiesel, I can see mention of import video in the pdf manual, it says:-
Import Video...imports video in a form of frame sequence and saves the extracted frames as images.
I panned really slowly to avoid jerky stills, but I wouldnt want e.g. 1 still per second as I would have thousands of stills. I wonder what extraction options there are. I also will need to mask the background out as its in a museum and if it works on what it sees it will emit smoke signals !
page 17 of the metashape pdf manual doesnt have anything on video and use of, (p17 is titled reconstruction parameters) I have searched on the term video and found nothing, ditto 4k.
I envisaged another video editing prog to get exactly the stills I want from it.

Steve

Alexey Pasumansky

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Hello Steve,

Currently Import Video option allows only to extract every Nth frame from the sequence in the specified time frame. The extracted frames will be put to the user-defined folder and automatically added to the project workspace.

See the screenshot  of the "import video" dialog below:
Best regards,
Alexey Pasumansky,
Agisoft LLC

Kiesel

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Hi Steve003,

sorry was an older manual for version 1.5, where I have looked in. In actual manual it is on page 21.

Best regards

Kiesel

Steve003

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Hi,
as I was panning slowly as my 4K camcorder seems to give jerky video on normal panning despite trying the fastest card and best settings, and its £1400 and full manual control, every 10th frame would give far too many images.
I am interested to know, if a subject is 2 meter long, and I am standing 2 metres away, how many seconds panning from start to finish might one need to do to get a suitable number of frames if every 10th frame is used. I was taking maybe 16 seconds to do so. I later did a faster scan maybe 8 secs as another test.

I would have to on this occasion manually edit out the backgrounds on some of the frames in photoshop, as it goes from a shot of the subject and a lot of background in the museum when starting the scan to just the subject.

Steve

BKing

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Hi,
as I was panning slowly as my 4K camcorder seems to give jerky video on normal panning despite trying the fastest card and best settings, and its £1400 and full manual control, every 10th frame would give far too many images.
I am interested to know, if a subject is 2 meter long, and I am standing 2 metres away, how many seconds panning from start to finish might one need to do to get a suitable number of frames if every 10th frame is used. I was taking maybe 16 seconds to do so. I later did a faster scan maybe 8 secs as another test.

I would have to on this occasion manually edit out the backgrounds on some of the frames in photoshop, as it goes from a shot of the subject and a lot of background in the museum when starting the scan to just the subject.

Steve

Hi Steve!

The longer the exposure time the slower you have to pan/move the camera to avoid motion blured pictures.

You don't need to edit out backgrounds. You can use the masking feature in metashape.

Thomas

Steve003

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Hi,
VERY IMPORTANT QUESTION !
I read that Metashape works with the exif data in order to perform its magic.
If I am hitting a stills capture button in a video playback or editing prog, capturing stills from the video, will those have that exif data the same as a stills camera would generate ?
would such images captured that way work in Agisoft ?

I need to capture stills at moments in the video I know I need them, two stills might be 3 seconds apart, using Agisoft  inbuilt image capture every 10th frame will see far too many stills compared to what is required for 60% overlap. If I end up with 10x as many images as required it will make the prog struggle if not fail ? Some of those are bound to be between keyframes, keyframes give the best image usually, if it captured every lets say 5th keyframe that might be better.

agreed a slow shutter speed means a slower pan, but a dull and poorly lit museum needs a slow shutter speed if I am to have good depth of field.

Also the Sony AX100E I have seems to have an inbuilt inability to pan without causing jerkiness, as I have tried it in sunshine on everything from 1/50 to 1/600.

My subject matter pan starts off showing a load of exhibits in the background then becomes in seconds just my subject then the ceiling creeps in then the floor, all that extra background stuff seems to me a distraction, likely to cause failure. I am familiar with mask from model, but if the background isn't enough in the sequence to create a decent mesh, editing it out can see one faced with a poorly defined mush to start with.

I have had failures where I am convinced pre editing in photoshop would give a better result.

Steve003