Conventional optical systems used for whole-field specklegram reconstruction are limited by the size of the lenses, the uniformity of the collimated beam, and the off-axis capability. Outside the Fresnel and paraxial regions, the fringe patterns will suffer from various aberrations. The maximum obtainable sensitivity, therefore, is severely restrained. A new optical system and instrument-the high-frequency optical Fourier transform analyzer-specifically designed for whole-field specklegram reconstruction, can extrapolate the spectrum beyond the passband. It can extract information at any point within the hemisphere at which diffraction occurs. It also minimizes aberrations, allowing the sensitivity of speckle metrology to be increased to levels commensurate with those of moire interferometry.