[Top][All Lists]

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [libcvd-members] FAST corner detection--- RFC

From: Edward Rosten
Subject: Re: [libcvd-members] FAST corner detection--- RFC
Date: Tue, 12 Jun 2007 11:03:27 -0600 (MDT)

On Mon, 11 Jun 2007, twd20 wrote:

I'm a bit concerned about the non max suppression score.  The max
threshold proposal makes it very sensitive to the exact value of the
centre pixel.  For a sharp dark corner on a light background it
essentially finds the darkest centre pixel within the corner region.

That is true. However the max threshold can be used rethresholding or locally adaptive thresholding. So, it's only as sensitive as theFAST detector.

It occurred to me that maybe the score should be the (non-integer)
length of the arc that is above the threshold - non-integer because of
bilinear interpolation between adjacent ring scores.  This will tend to
push the maximal score out into the extrema of the corner - which (I
hope) will tend to be more repeatable at a high level of accuracy???

But I'm open to evidence that max threshold gives better repeatability.

Unknown. I expect that it will have more effect on localisation so the differences will be too small for the repeatability dataset.

For any choice, one can think of bad cases, such as having a long but faint contguous arc.


It might also be nice to rename the parameter in the non-max suppression
function to be max_corners not nonmax_corners since that's what you get
back (!).  This will only have the effect of changing the doxygen
documentation and shouldn't break anything.


We could provide the following functions:




That way you can choose the detector, the scoring function (or use your own) or use nonmax suppression on what ever you want.

Now just getting a bunch of corners requires more lines of code. So I propse also providing a two helper functions:


I will pretty much always use the first one of those.

Also agree with Georg that you should be able to find out which version
of the function you're using.  That way when optimising code that needs
to be fast, we won't have to spend time checking whether a configuration
error is preventing SCREAMING LORD SIMD from making an appearance.

Yes. However, the place to check should be in the output of the configure script.

Try the brand new configure script. :-)


reply via email to

[Prev in Thread] Current Thread [Next in Thread]