How can I photograph a 100 m long specimen from above at fixed time intervals?
Asked 2/21/2014
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I need to record a specimen about 100 m long and 3 m wide from directly overhead at regular time intervals, then analyze the images over time. Accuracy is important.
I’m considering mounting multiple cameras above the specimen so they can all trigger at the same time and later be combined into one image. I’m also wondering whether there is a moving camera system that can automatically scan the full length, similar to a panorama setup.
What established imaging approaches are suitable for this kind of long subject, and what issues should I watch for when stitching or synchronizing cameras?
Originally by Photography Stack Exchange contributor. Source · Licensed CC BY-SA 4.0
Photography Stack Exchange contributor
12y ago
2 Answers
8
There's a limited amount of information on what the experiment actually is, so it's hard to give a full answer. If the question is updated with more detail I'll try to revise this answer.
1.I am thinking of having multiple cameras hanging on the top to capture the image. Can we control all the cameras to take picture at the same time and later combine them into one?
Yes, that's not a problem. There are even free applications such as Microsoft Image Composite Editor and Hugin. That said, depending on what your experiment is the Parallax Errors introduced could become a significant problem.
2.Is there any camera device which moves and captures the entire photo by itself allowing some time lag. (some kind of panorama picture with automation).
Yes, they are called Line Scan cameras, typically they're used in industrial control systems and they just take an image of a single line of pixels at a time and the camera moves over the length of the experiment.
You'd probably have to build the rig / mounting to make it cover your experiment.
You can also rig a normal camera, like a DSLR to a rig or dolly which can also be automated.
3.Approximately how many cameras require for such a job.
Anything from one upwards. For a 3D object you may want more cameras to give you perspective or create a stereoscopic image or for a fast moving object you may want more cameras to keep up with the action.
Originally by user14028. Source · Licensed CC BY-SA 4.0
user14028
12y ago
0
Generated from our catalog & community — verify before relying on it.
Yes—using multiple overhead cameras triggered at the same time is a practical approach, and the images can be stitched later. Panorama/stitching software such as Hugin or Microsoft Image Composite Editor can do this.
The main caution is parallax error: if the cameras are not truly overhead, or if the specimen has any height/depth variation, stitching may be inaccurate. For measurement work, consistent mounting geometry is critical.
A moving system that scans the subject also exists in principle: this is generally called line-scan imaging. It’s often used when a long subject needs to be captured continuously.
If you use multiple cameras, synchronized triggering is possible. One community suggestion was Canon compact cameras running CHDK, which can support scripted shooting and USB-based synchronization across multiple cameras.
How many cameras you need depends on the field of view, mounting height, lens choice, and the precision you require, so it can’t be determined from the information given alone.
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