Can software correct an angled photo of a whiteboard so it looks straight-on?
Asked 7/18/2015
6 views
2 answers
0
I need to photograph a whiteboard from an off-angle position because people block a straight-on view. Since the whiteboard is a flat plane, can software transform the image so the board appears front-facing and 2D, preserving the writing on it? I only care about the content on the flat board, not the surroundings. Is this possible for still images, and can it also be done in real time for a fixed camera video feed?
Originally by Photography Stack Exchange contributor. Source · Licensed CC BY-SA 4.0
Photography Stack Exchange contributor
11y ago
2 Answers
2
There are transformations that you can apply to achieve some of what you're after, but there's not enough information in the source photo to come up with the final photo. For example, look at the heads of the two bolts. In the final photo, you can see that they're hexagonal, with round washers. But in the source photo you're looking at them from the side, so you have no way to know what shape they are: they could be round or hexagonal or square. Furthermore, there's extra information that you need to hide: in the source photo you see the edge of the sign, but this needs to be hidden when you change the viewing angle so that you're looking at the sign straight on.
For a whiteboard, however, the problem is much simpler because the surface is very flat and the thickness of the pen strokes is negligible. That is, the image on the whiteboard exists in a single plane. You can therefore use an affine transformation to stretch the image vertically, compress the bottom horizontally, and stretch the top horizontally. It should work pretty well provided you get enough resolution from your camera.
Originally by user4262. Source · Licensed CC BY-SA 4.0
user4262
11y ago
0
Generated from our catalog & community — verify before relying on it.
Yes—if the subject is a flat surface like a whiteboard, this is essentially a perspective correction (also called a perspective transform or keystone correction). Many image editors, including Photoshop and GIMP, can do this for still images.
The important limitation is that software can only remap information that’s actually visible in the original image. It works much better for a flat whiteboard with writing than for a 3D object, because a tilted photo of a 3D subject hides or distorts details that cannot be recovered. Also, if the viewing angle is extreme, expect some loss of quality or readability after correction.
So for a whiteboard: yes, often practical. For dramatic viewpoint changes or anything with depth: only partially.
For real-time video, the same kind of transform is possible in principle when the camera is fixed, because the correction stays the same from frame to frame. But that moves more into video-production/computer-vision software than basic photo editing.
Recommended products
UniqueBot
AI11y ago
Your Answer
Related Questions
How can I capture a large whiteboard with enough detail using stitched photos or focus stacking?
How can I identify and reduce the light source causing glare on a whiteboard?
Can I create a linear side-scrolling panorama from a moving car or train?
What kind of tripod setup lets me photograph an object lying flat on the floor from directly above?
Can an A4/letter inkjet print extra-long panoramic pages using a custom paper size?