What is optical flow analysis?

Optical-flow methods are based on computing estimates of the motion of the image intensities over time in a video. The flow fields can then be analyzed to produce segmentations into regions, which might be associated with moving objects.

What is an optical flow field?

Optical flow fields describe the temporal shift of observable gray value structures in image sequences (Nagel 85). Various approaches have been suggested to estimate optical flow fields from image sequences – see, for example, Nagel 83 + 84 + 85 or Hildreth 83 for a review of the literature.

What is the optical flow equation?

Ixu + Iyv + It = 0, where the partial derivatives of I are denoted by subscripts, and u and v are the x and y components of the optical flow vector. This last equation is called the optical flow constraint equation since it expresses a constraint on the components u and v of the optical flow.

How do optical flow sensors work?

This sensor is based on the idea of optical mouse (image sensor). It senses the image (camera sensor) of a surface or an object by taking very large number of images (frames) in short time. When the position of the object change the corresponding pixels position change.

How is the motion field and optical flow field related?

Thus the optical flow field is zero, but the motion field is not (no visible brightness change) (b) A fixed sphere is illuminated by a moving source Îthe shading of the image changes. Thus the motion field is zero, but the optical flow field is not (brightness change due to other factors than motion).

What is the problem of optical flow in photography?

Optical flow is the motion of objects between consecutive frames of sequence, caused by the relative movement between the object and camera. The problem of optical flow may be expressed as:

How is optical flow used in object detection?

You can also combine Object Detection with this method to only estimate the flow of pixels within the detected bounding boxes. This way you can track all objects of a particular type/category in the video. Tracking a single object using optical flow. 5. Lucas-Kanade: Sparse Optical Flow

Which is the correct equation for optical flow?

Optical Flow •Brightness Constancy •The Aperture problem •Regularization •Lucas-Kanade •Coarse-to-fine •Parametric motion models •Direct depth •SSD tracking •Robust flow •Bayesian flow Start with an Equation: Brightness Constancy