recalagerigide_num.c File Reference

rigid registration of two grayscale images More...

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Detailed Description

rigid registration of two grayscale images

Usage: recalagerigide_num in1 in2 seuil [init] out

Description:

Rigid registration of two grayscale images. Let X and Y be two images, given respectively by in1 and in2. This procedure identifies the parameters of a rigid deformation R such that the "distance" between R(X) and Y is a local minimum. The distance D(Z,Y) between two images Z and Y is defined by:

D(Z,Y) = sum { (Z[i] - Y[i])^2 ; for all i in support(Y) }

The rigid deformation R is defined as the composition (in this order) of a zoom, a rotation, and a translation.

In 2d, the parameters are:

• hx : parameter for the scaling in direction x
• hy : parameter for the scaling in direction y
• theta : angle (in degrees) of the rotation around (0,0)
• tx : parameter for the translation in direction x
• ty : parameter for the translation in direction y

The output parameter out is the name of a text file in which these values will be written (type "e" list format, see doc/formats.txt).

The parameter seuil makes it possible to eliminate outliers: points i such that (Z[i] - Y[i])^2 > seuil^2 are not taken into account. A value 255 for this parameter means no outlier elimination.

The optional parameter init makes it possible to give, in the same format as the output, an initial deformation which is "close" to the expected one. The default initialisation is the identity (parameters 0, 1, 1, 0, 0).

Types supported: byte 2d

Category: geo

Author:

Michel Couprie