  Based on optical correlations, ghost imaging is usually reconstructed by
computer algorithm from the acquired data. We here proposed an alternatively
high contrast naked-eye ghost imaging scheme which avoids computer algorithm
processing. Instead, the proposed scheme uses a photoelectric feedback loop to
realize the multiplication process of traditional ghost imaging. Meanwhile, it
exploits the vision persistence effect to implement integral process and to
generate negative images observed by naked eyes. To realize high contrast
naked-eye ghost imaging, a special pattern-scanning architecture on a low-speed
light-modulation mask is designed, which enables high-resolution imaging with
lower-order Hadamard vectors and boosts the imaging speed as well. Moreover,
two kinds of feedback circuits, the digital circuit and the analog circuit, are
presented respectively, which can achieve high-speed feedback operation on the
light intensity. With this approach, we demonstrate high-contrast real-time
imaging for moving objects.
