To simulate digital detector's saturation and blooming effect. The blooming is along the read-out direction, perpendicular to the charge transfer direction. Charge clumpy overflows the pixel well will flow to two oposite directions with nearly same charges.
Work together with chargeflow() function.
Parameters:
GSImage: a GalSim Image of a chip;
nsect_x: number of sections divided along x direction;
nsect_y: number of sections divided along y direction.
Return: a saturated image array with the same size of input.