Not understanding how calcOpticalFlowPyrLK outputs found points

asked 2017-07-25 11:30:15 -0600

im not quite sure how to understand calcOpticalFlowPyrLK.

If im giving in a picture a with features fa on in also as a picture b, is it correct, that the feature list fb is always as big as fa? and i can figure out which features actually have been tracked by going though the "status" output looking for when it is 1?

so if the 3rd status uchar is 1 then this means that the position of the 3rd feature of fa in picture a is the position of the 3rd feature in fb in picture b

what is filled in fb if there is not a 1 in the status list for the corresponding feature?

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answered 2017-07-27 00:41:21 -0600

Tetragramm

7376 ●13 ●37

You are correct.

As for what is in fb if status is not 1, it is undefined. It's likely the last value that failed the validity check, but it could also be the starting value, or anything else, including NaN. Do not use these values.