Can parallax be used to remove thin foreground objects from a photo?
Asked 11/14/2018
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If a distant scene is partially blocked by a thin foreground object, such as a lamp post or tree, can taking multiple photos from slightly different sideways positions help remove the obstruction? For example, if the background is about 100 meters away and the obstruction is around 30 meters away, shifting the camera laterally changes the foreground object's position in the frame. Is there a known technique or common name for using this effect to create a clean final image?
Originally by Photography Stack Exchange contributor. Source · Licensed CC BY-SA 4.0
Photography Stack Exchange contributor
7y ago
2 Answers
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The phenomenon you're describing is called parallax. I've heard the technique called either "Parallax Removal" or the "X-Ray Brush."
Taking 2 or more pictures of an object in one plane by moving the camera in a second, parallel plane. Objects not on the target plane will "move" relative to the target plane as a result.
You can do layer them into a "clean" image manually by lining up the layers and erasing the top layer to reveal the underlying layer without the offending object.
I generally leverage Smart Objects in Photoshop for this. You'll need to take at least 3 images, being careful to keep your camera and subject on their own planes, then line them up and convert the layers into a smart object. Then select Layer > Smart Objects > Stack Mode > Median to automatically select the average pixel, and because you have two pixels of the desired object, and one of the offending object, you'll get the desired pixel every time.
This doesn't work well with things that aren't stationary (leaves, water, etc).
Originally by user68136. Source · Licensed CC BY-SA 4.0
user68136
7y ago
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Generated from our catalog & community — verify before relying on it.
Yes. The effect is parallax, and the approach is often described as parallax removal. By moving the camera sideways and taking multiple frames, objects at different distances shift relative to each other. That can reveal parts of the background hidden in one shot but visible in another.
In practice, take at least 2–3 images while moving the camera in a roughly parallel direction and keeping the target scene framed as consistently as possible. Then align the images in editing software and combine them so the obstructing foreground object is masked out, revealing clean background from another frame.
This can be done manually with layers and masking, or with a median stack in software such as Photoshop if you have several aligned frames. It works best for thin obstructions and scenes that stay still between exposures.
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