ning 25 will be assigned a value of <code>KLT_NOT_FOUND</code>.

<li> <code>KLT_SMALL_DET</code> (-2) indicates that the feature has been lost due to
the 2 by 2 gradient matrix having a small determinant.

<li> <code>KLT_MAX_ITERATIONS</code> (-3) means that the feature has been lost 
because the number of iterations exceeded the maximum allowable.

<li> <code>KLT_OOB</code> (-4) means that the feature has been lost 
because it was out of bounds (i.e., it was too close to the image border).

<li> <code>KLT_