A method of processing a holographic image, the method comprising: generating a first complex holographic image having a first resolution, i.e. pixel count, by performing frequency transformation on input image data having the first resolution; scaling the first complex holographic image having the first resolution to a second complex holographic image having a second resolution greater than the first resolution; encoding complex values corresponding respectively to pixels of the second resolution in the second complex holographic image that has been scaled, into integer values; and generating a computer generated hologram, CGH, image having the second resolution by using the encoded integer values, wherein the scaling of the first complex holographic image comprises up-scaling the first complex holographic image of the first resolution to the second complex holographic image of the second resolution by performing interpolation, and characterized in that the scaling of the first complex holographic image comprises: separating the first complex holographic image into a first real image and a first imaginary image having the first resolution; generating a second real image and a second imaginary image having the second resolution by performing the interpolation respectively on the first real image and the first imaginary image; and generating the second complex holographic image by synthesizing the second real image and the second imaginary image with each other. generating a first complex holographic image having a first resolution, i.e. pixel count, by performing frequency transformation on input image data having the first resolution; scaling the first complex holographic image having the first resolution to a second complex holographic image having a second resolution greater than the first resolution; encoding complex values corresponding respectively to pixels of the second resolution in the second complex holographic image that has been scaled, into integer values; and generating a computer generated hologram, CGH, image having the second resolution by using the encoded integer values, wherein the scaling of the first complex holographic image comprises up-scaling the first complex holographic image of the first resolution to the second complex holographic image of the second resolution by performing interpolation, and characterized in that the scaling of the first complex holographic image comprises: separating the first complex holographic image into a first real image and a first imaginary image having the first resolution; generating a second real image and a second imaginary image having the second resolution by performing the interpolation respectively on the first real image and the first imaginary image; and generating the second complex holographic image by synthesizing the second real image and the second imaginary image with each other. separating the first complex holographic image into a first real image and a first imaginary image having the first resolution; generating a second real image and a second imaginary image having the second resolution by performing the interpolation respectively on the first real image and the first imaginary image; and generating the second complex holographic image by synthesizing the second real image and the second imaginary image with each other.