Editing Continuity equation (section)

== Computer vision ==

{{Main|Optical flow}}

In [[computer vision]], optical flow is the pattern of apparent motion of objects in a visual scene. Under the assumption that brightness of the moving object did not change between two image frames, one can derive the optical flow equation as:{{citation needed|date=April 2024}}
<math display="block">\frac{\partial I}{\partial x}V_x + \frac{\partial I}{\partial y}V_y + \frac{\partial I}{\partial t}
= \nabla I\cdot\mathbf{V} + \frac{\partial I}{\partial t}
= 0</math>
where
* {{math|''t''}} is time,
* {{math|''x'', ''y''}} coordinates in the image,
* {{math|''I''}} is the image intensity at image coordinate {{math|(''x'', ''y'')}} and time {{mvar|t}},
* {{math|'''V'''}} is the optical flow velocity vector <math>(V_x, V_y)</math> at image coordinate {{math|(''x'', ''y'')}} and time {{mvar|t}}