  Sample selection is a necessary preparation for weak lensing measurement. It
is well-known that selection itself may introduce bias in the measured shear
signal. Using image simulation and the Fourier_Quad shear measurement pipeline,
we quantify the selection bias in various commonly used selection function
(signal-to-noise-ratio, magnitude, etc.). We proposed a new selection function
defined in the power spectrum of the galaxy image. This new selection function
has low selection bias, and it is particularly convenient for shear measurement
pipelines based on Fourier transformation.
