When a conventional stereoscopic display is viewed without three-dimensional (3D) glasses, image blurs, or ghosts, are visible due to the fusion of stereo image pairs. This artifact severely degrades 2D image quality, making it difficult to simultaneously present clear 2D and 3D content. To overcome this limitation, we recently proposed a method to synthesize ghost-free stereoscopic images. Our method gives binocular disparity to a 2D image and drives human binocular disparity detectors by the addition of a quadrature-phase pattern that induces spatial subband phase shifts. The disparity-inducer patterns added to the left and right images are identical except for the contrast polarity. Physical fusion of the two images cancels out the disparity-inducer components and makes only the original 2D pattern visible to viewers without glasses.