image processing - Camera properties for 3d using specular reflection -


could 1 in clarifying following description taken article "local shape mirror reflection" savarese, chen , perona.

"let c center of projection of camera. image plane positioned l distance units in front of c, perpendicular view direction v. given scene point p let q image of p observed on image plane through specular reflection on mirror surface @ r."

  1. to understanding both c, v , l properties of camera, how can find them?
  2. as p moves along scene plain q , r shift respectively c,v , l constant or should new center of projection, image plane , view direction calibrated separately each point?

image setup of system:

c , v not intrinsic properties of camera, location , orientation. however, l focal length, intrinsic parameter. both intrinsic , extrinsic parameters can recovered through calibration procedure. if matlab, google jean-yves bouguet's camera calibration toolkit. has been ported opencv since forever, if you'd rather c or c++.

the extrinsic parameters change if camera moved relative scene. intrinsic ones change if in lens changed, e.g. refocusing or changing aperture (the f-stop). neither change exposure time (it affects how many photons reach sensor).

note today's lens mounts (screw, bayonet) , sensor sizes , resolutions (a few tens of mm , several megapixels across) it's very easy "move" camera: touching lens enough move center few pixels , axis few minutes of arc. if repeatability paramount may want getting special/custom lens mounts , rigid camera stand/support. in case software need robust respect small camera motions


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