spatial_frequency_weight

The SPATIAL_FREQUENCY_WEIGHT parameter specifies the weighting applied to each collimator when combining them to form a back projection image. SPATIAL_FREQUENCY_WEIGHT is not set directly by the user, but is controlled through the following three parameters:

UNIFORM_WEIGHTING - If set, then weight each collimator by the inverse of its FWHM

NATURAL_WEIGHTING - If set, all collimators have equal weight

TAPER - (scalar) If nonzero, a factor to apply to SPATIAL_FREQUENCY_WEIGHT determined as follows for each detector:
exp ((-.89 * taper/FWHM)^2 < 50.)

Note 1: UNIFORM_WEIGHTING preferentially weights the noisy high-frequency components.

Note 2: NATURAL_WEIGHTING is better for extended sources while UNIFORM_WEIGHTING provides greater sensitivity for compact sources. Taper can be used to smooth out the image to avoid over-resolution.