Two-wavelength interferometry that is based on a Fourier-transform met
hod has been investigated. A phase profile at a synthetic wavelength h
as been measured from a two-wavelength interferogram with two spatial
carrier frequencies. A phase error caused by the difference between mo
dulation intensities at two wavelengths has been theoretically and num
erically analyzed. A phase map without the error can be obtained from
a power-spectrum adjustment in the two-wavelength interferogram. (C) 1
998 Optical Society of America.