Abstract: A method for generating a holographic image, a signal processor, a holographic image display device, a wearable apparatus, and an onboard head-up display apparatus. The method comprises: performing holographic transformation on the basis of a target amplitude phase distribution of a target image to obtain a holographic phase image; performing phase quantization of the holographic phase image to obtain a quantized holographic image; performing inverse holographic transformation of the quantized holographic image to obtain a reconstructed image; if the reconstructed image satisfies a preset condition, determining that the quantized holographic image is a target holographic image; if not, constraining the amplitude phase of the reconstructed image and, on the basis of the amplitude phase constrained image, continuing iteration.