There is provided a method of projection using an optical element (502,602) having spatially variant optical power. The method comprises combining Fourier domain data representative of a 2D image with Fourier domain data having a first lensing effect (604a) to produce first holographic data. Light is spatially modulated (504,603a) with the first holographic data to form a first spatially modulated light beam. The first spatially modulated light beam is redirected using the optical element (502,602) by illuminating a first region (607) of the optical element (602) with the first spatially modulated beam. The first lensing effect (604a) compensates for the optical power of the optical element in the first region (607). Advantageous embodiments relate to a head-up display for a vehicle using the vehicle windscreen (502,602) as an optical element to redirect light to the viewer (505,609).

A holographic display device for computing a video hologram of a scene is disclosed. The scene comprises a multitude of object points. The holographic display device comprises at least one light modulator means. Said holographic display device is configured to perform the steps of (a) defining a visibility region within a periodicity interval of the video hologram of the scene to be reconstructed; (b) for each object point, defining a modulator region by the defined visibility region together with each object point of the scene to be reconstructed, where a sub-hologram of an object point of the scene to be reconstructed is computed for each modulator region, and where an entire video hologram is created by superposition of said sub-holograms; (c) determining complex hologram values of a sub-hologram in a modulator region from a wave front of an object point to be reconstructed by computing modulation functions of an imaging element which is modeled in the respective modulator region of said holographic display device, and in whose focal point the object point to be reconstructed lies, where the sub-hologram of said object point is computed using the modulation functions, and (d) encoding the video hologram of the scene into the screen means.

A holographic display device for computing a video hologram of a scene is disclosed. The scene comprises a multitude of object points. The holographic display device comprises at least one light modulator means. Said holographic display device is configured to perform the steps of (a) defining a visibility region within a periodicity interval of the video hologram of the scene to be reconstructed; (b) for each object point, defining a modulator region by the defined visibility region together with each object point of the scene to be reconstructed, where a sub-hologram of an object point of the scene to be reconstructed is computed for each modulator region, and where an entire video hologram is created by superposition of said sub-holograms; (c) determining complex hologram values of a sub-hologram in a modulator region from a wave front of an object point to be reconstructed by computing modulation functions of an imaging element which is modeled in the respective modulator region of said holographic display device, and in whose focal point the object point to be reconstructed lies, where the sub-hologram of said object point is computed using the modulation functions, and (d) encoding the video hologram of the scene into the screen means.

An analytical method for computing a video hologram for a holographic reproduction device having at least one light modulation means is disclosed, wherein a scene split into object points is encoded as a whole hologram and can be seen as a reconstruction from a visibility region, located within a periodicity interval of the reconstruction. The visibility region, together with each object point of the scene to be reconstructed, defines a sub-hologram and the whole hologram is generated from a superposition of sub-holograms, wherein the complex hologram values of a sub-hologram are determined from the wave front of the respective object point to be reconstructed in a modulator region of the light modulation means, by calculating and evaluating the transmission or modulation functions of an imaging element formed in the modulator region. The object point to be reconstructed is located in the focal point of the imaging element.

A holographic display apparatus and a hologram optimization method for the apparatus are provided. The holographic display apparatus includes a focus-forming optical element configured to form a plurality of foci by receiving plane waves; a collimating lens configured to propagate, as plane waves, light incident through the plurality of foci; and a spatial light modulator configured to generate a holographic image by overlapping a plurality of plane waves incident from the collimating lens.

There is provided a method of projection using an optical element having spatially variant optical power. The method comprises combining Fourier domain data representative of a 2D image with Fourier domain data having a first lensing effect to produce first holographic data. Light is spatially modulated with the first holographic data to form a first spatially modulated light beam. The first spatially modulated light beam is redirected using the optical element by illuminating a first region of the optical element with the first spatially modulated beam. The first lensing effect compensates for the optical power of the optical element in the first region.

There is provided a method of projection using an optical element having spatially variant optical power. The method comprises combining Fourier domain data representative of a 2D image with Fourier domain data having a first lensing effect to produce first holographic data. Light is spatially modulated with the first holographic data to form a first spatially modulated light beam. The first spatially modulated light beam is redirected using the optical element by illuminating a first region of the optical element with the first spatially modulated beam. The first lensing effect compensates for the optical power of the optical element in the first region.