[ptx] dirty lens and autopano-sift?

[manouchk]

Le Lundi 30 Janvier 2006 11:12, Sebastian Nowozin a écrit :

Hy, thank you for considering my mail! (I've such a low rate of respost in 
most mailing-list I participate)

> Hi Bruno,
>
> nice idea to use only the HS and drop the rest.

I tried the Bruno's methods and the results is that autopano-sift does not 
find any control point!

May be there is a need to tweek autopano-sift parameters ?

Sebastian your code modification is somehow the same thing as Bruno or not?

> On Mon, Jan 30, 2006 at 12:19:52PM +0000, Bruno Postle wrote:
> > Unfortunately autopano-sift depends on the brightness intensity to
> > locate features, so you need to flatten the image and discard two of
> > the colour channels to get something with usable features.
>
> Alternatively, if you are a little familar with programming, you can
> try modifying the file "src/util/BasicImagingInterface.cs", which has a
> method.
>
> public double Convert (byte r, byte g, byte b) {
> 	return ((r + g + b) / (255.0 * 3.0));
> }
>
> There the intensity value is calculated, here by just taking the mean
> value of all. You can do a simple RGB to HSV colorspace
> transformation, (http://answers.google.com/answers/threadview?id=68501)
> and return the intensity based on that value.
>
> (untested code follows)
>
> public double Convert (byte r, byte g, byte b) {
>     int x = (r < g) ? r : g;
>     x = (x < b) ? x : b;
>
>     int v = (r > g) ? r : g;
>     v = (v > b) ? v : b;
>
>     if (v == x)
>         return (v / 255.0);
>
>     int f = (r == x) ? (g - b) : ((g == x) ? (b - r) : (r - g));
>     int i = (r == x) ? 3 : ((g == x) ? 5 : 1);
>
>     // Only use hue and saturization
>     return ( ( ((i - f) / ((double)(v - x))) +
>         ((v - x) / ((double) v)) ) / (255.0 * 2.0));
> }
>
> Greetings,
> Sebastian

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