Add Strehl computation

maoppy/psfmodel.py

@@ -477,6 +477,15 @@ class ParametricPSFfromPSD(ParametricPSF):
         f2D *= self.getpix2freq()
         return f2D
     
+    def strehlOTF(self,x0):
+        otf = self.otf(x0,_caller='self')
+        otf_diff = self._otf_diffraction()
+        return _np.real(_np.sum(otf)/_np.sum(otf_diff))
+    
+    def strehlMarechal(self,x0):
+        _,sig2 = self.psd(x0)
+        return _np.exp(-sig2)
+    
     def psd(self,x0):
         raise ValueError("ParametricPSFfromPSD is not to be instantiated. the `psd` method must be override in the subclasses")