Sensor modulation transfer function measurement using band-limited laser speckle

A new methodology for image sensor modulation transfer function measurement using band-limited laser speckle is presented. We use a circular opal milk glass diffuser illuminated by a 5 mW He-Ne laser and a linear polarizer to generate band-limited speckle on the sensor. The power spectral density cut-off frequency of the speckle is chosen to be twice that of the sensor Nyquist frequency by placing the sensor at the specific Z location along the optical axis. For the speckle input, we calculate the power spectral density at the sensor using the Rayleigh-Sommerfeld integral and then measure the output power spectral density for the speckle pattern captured by the sensor. With these data, the two-dimensional image sensor modulation transfer function (MTF) is calculated.