INTERFERO

The (complex) interferogram is computed, with or without subtraction
of the reference phase. The reference phase is subtracted if there is
a 2d-polynomial in the **products result file** (result of step FLATEARTH). It is
not subtracted if this is not in the **result file** or if
the number of coefficients is set to 0.

The complex interferogram minus reference phase is defined as:

(W1) |

Where:

denotes the complex conjugated;

denotes a pointwise multiplication;
*I* is the complex interferogram;
*M* is the complex master image;
*S* is the complex (resampled) slave image;
*R* is the complex (amplitude 1) reference phase.

The phase image (of the complex interferogram minus reference phase) is defined as:

(W2) |

Where:

is the four quadrant arc tangent;

is the phase image;
*I* is the complex interferogram;

This is identical to

(W3) |

Multilooking can be performed to reduce noise. Usually a ratio of (line:pixel) = 5:1 between the factors is chosen to obtain more or less square pixels (20x20 for factors 5 and 1). (The resolution decreases of course if multilooking is applied.)