V1 Readme + rangement

ongoing/ASIFT_tests/demo_ASIFT_src/libNumerics/homography.cpp

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+// Authors: Unknown. Please, if you are the author of this file, or if you 
+// know who are the authors of this file, let us know, so we can give the 
+// adequate credits and/or get the adequate authorizations.
+
+#include "homography.h"
+
+namespace libNumerics {
+
+/// Constructor.
+Homography::Homography()
+: m_H( matrix<double>::eye(3) )
+{}
+
+/// Put to identity.
+void Homography::setId()
+{
+    m_H = matrix<double>::eye(3);
+}
+
+/// Set to translation.
+void Homography::setTrans(double dx, double dy)
+{
+    setId();
+    m_H(0,2) = dx;
+    m_H(1,2) = dy;
+}
+
+/// Set to zoom.
+void Homography::setZoom(double zx, double zy)
+{
+    setId();
+    m_H(0,0) = zx;
+    m_H(1,1) = zy;
+}
+
+/// Apply homography.
+void Homography::operator()(double& x, double& y) const
+{
+    vector<double> m(3);
+    m(0) = x;
+    m(1) = y;
+    m(2) = 1.0f;
+    m = m_H * m;
+    double z_1 = 1.0 / m(2);
+    x = m(0) * z_1;
+    y = m(1) * z_1;
+}
+
+/// Compose homographies.
+Homography Homography::operator*(const Homography& rhs) const
+{
+    Homography h;
+    h.m_H = m_H * rhs.m_H;
+    h.normalize();
+    return h;
+}
+
+/// Inverse homography.
+Homography Homography::inverse() const
+{
+    Homography h;
+    h.m_H = m_H.inv();
+    h.normalize();
+    return h;
+}
+
+/// Put coef(2,2) to 1.
+void Homography::normalize()
+{
+    m_H /= m_H(2,2);
+}
+
+} // libNumerics