Computer Vision Foundations · free preview
Seeing Around Corners
A wall corner casts a moving shadow that carries the hidden scene, and an inversion turns the shadow back into a picture.
1. A corner as an accidental camera
A corner as an accidental camera
2. Writing the hidden scene into the ground
Writing the hidden scene into the ground
3. Integrating is invertible with care
Integrating is invertible with care
4. A one-dimensional video of a hidden walk
A one-dimensional video of a hidden walk
5. What the corner camera measures
A camera watches the ground beside an outside wall corner at night, and a person walks on the hidden side. The recorded ground brightness changes only slightly, by about a thousandth of the background. What is the camera recording?
6. Why the derivative is the recovery
The ground illumination beside a corner equals the integral of the hidden image over azimuth, up to each ground position. What operation on the ground brightness recovers the hidden image?
7. The hidden slice
The one-dimensional hidden image takes the values and at two adjacent azimuths, and the ground illumination accumulates it. Compute the increase in ground brightness across that pair of azimuths and write the number.
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