Systems and methods for holographic projection
A holographic system comprises an image processor, a hologram calculator and a display driver. The image processor is arranged to determine first and second secondary images by sampling the pixel values of a primary image at a regular array of sampling positions. The hologram calculator is arranged to determine a hologram of each secondary image. The display driver is arranged to display each hologram in rapid succession on a display device, first and second times, so as to reconstruct each secondary image from the respective hologram such that respective first and second arrays of image pixels corresponding to the primary image are perceivable. Image pixels of the reconstruction of the second secondary image are interposed between image pixels of the reconstruction of the first secondary image in the first direction.
1. A holographic system comprising:
an image processor arranged to determine a plurality of secondary images from a primary image, each secondary image formed by sampling pixel values of the primary image at a regular array of sampling positions, wherein a first secondary image is formed using a regular array of first sampling positions and a second secondary image is formed using a regular array of second sampling positions, wherein the second sampling positions are interposed between the first sampling positions in a first direction; and
one or more tangible, non-transitory computer-readable media comprising program instructions, wherein the program instructions, when executed by one or more processors of the holographic system, cause the holographic system to:
determine a hologram of each secondary image; and
cause display of each hologram in rapid succession on a display device so as to reconstruct each secondary image from the respective hologram such that a first array of image pixels, substantially corresponding to the primary image, is perceivable, wherein image pixels of the reconstruction of the second secondary image are interposed between image pixels of the reconstruction of the first secondary image in the first direction, wherein an aperture of the display device is orientated such that it is longer in a second direction than the first direction, wherein the second direction is orthogonal to the first direction, and wherein the image pixels formed to reconstruct each secondary image are more elongate and closely-packed in the first direction than the second direction; and
cause display of each hologram for a second time in rapid succession with a first time so as to reconstruct each secondary image from the respective hologram such that a second array of the image pixels is perceivable.
2. The holographic system of claim 1 , wherein the second array of the image pixels is translated in the second direction with respect to the first array of the image pixels in order that the second array of the image pixels interpose the first array of the image pixels in the second direction.
3. The holographic system of claim 1 wherein the program instructions, when executed by one or more processors of the holographic system, cause the holographic system to display each hologram for a second time with a grating function in the second direction so that the second array of the image pixels is translated in the second direction with respect to the first array of image pixels.
4. The holographic system of claim 1 wherein the first sampling positions are aligned with the second sampling positions in the second direction of the array such that image pixels of the reconstruction of the second secondary image are aligned with image pixels of the reconstruction of the first secondary image in the second direction.
5. The holographic system of claim 1 wherein the image processor is arranged to form a third secondary image using a regular array of third sampling positions and a fourth secondary image using a regular array of fourth sampling positions.
6. The holographic system of claim 5 wherein the fourth sampling positions are interposed between the third sampling positions in the first direction.
7. The holographic system of claim 6 wherein the program instructions, when executed by one or more processors of the holographic system, cause the holographic system to display a sequence of holograms corresponding to the first to fourth secondary images in rapid succession on the display device such that the first array of image pixels, substantially corresponding to the primary image, is perceivable, wherein image pixels of the reconstruction of the fourth secondary image are interposed between image pixels of the reconstruction of the third secondary image in the first direction.
8. The holographic system of claim 6 wherein each of the regular arrays of first to fourth sampling positions are different.
9. The holographic system of claim 1 wherein at least one of: (i) each secondary image comprises fewer pixels than the primary image, or (ii) each pixel of the primary image corresponds to only one secondary image such that the secondary images are combinable in order to fully form a composite representation of the primary image.
10. The holographic system of claim 1 wherein each hologram is displayed on the display device, and each displayed hologram is illuminated, in rapid succession such that the first array of the image pixels is formed on a display plane at substantially the same time or within an integration time of a human eye.
11. The holographic system of claim 10 , wherein the display device is a spatial light modulator.
12. The holographic system of claim 11 , wherein the display device is a liquid crystal on silicon (LCOS) spatial light modulator.
13. The holographic system of claim 1 , wherein the aperture of the display device comprises a rectangular perimeter of a pixel array of the display device.
14. The holographic system of claim 1 , wherein each regular array of sampling positions is a square array of sampling positions pixel such that each secondary image is square.
15. The holographic system of claim 1 , wherein the array of image pixels has a high aspect ratio.
16. The holographic system of claim 15 , wherein the aspect ratio is substantially 2:1.
17. The holographic system of claim 1 , wherein the image processor is further arranged to receive a target image for projection and to form the primary image.
18. The holographic system of claim 17 , wherein the primary image is an upscaled version of a target image.
19. A holographic system comprising:
a display device;
one or more processors; and
one or more tangible, non-transitory computer-readable media having program instructions stored therein, wherein the program instructions, when executed by the one or more processors, cause the holographic system to:
determine a plurality of secondary images from a primary image, each secondary image formed by sampling pixel values of the primary image at a regular array of sampling positions, wherein a first secondary image is formed using a regular array of first sampling positions and a second secondary image is formed using a regular array of second sampling positions, wherein the second sampling positions are interposed between the first sampling positions in a first direction of the array;
determine a hologram of each secondary image;
cause display of each hologram in rapid succession on the display device comprising a pixel array for a first time so as to reconstruct each secondary image from the respective hologram such that a first array of image pixels, substantially corresponding to the primary image, is perceivable, wherein image pixels of the reconstruction of the second secondary image are interposed between image pixels of the reconstruction of the first secondary image in the first direction;
cause display of each hologram in rapid succession on the display device for a second time, wherein the second time is immediately after the first time, so as to reconstruct each secondary image from the respective hologram such that a second array of image pixels is perceivable, wherein the second array of image pixels is translated in a second direction relative to the first array of images pixels; and
wherein an aperture of the display device is longer in the second direction than the first direction, wherein the second direction is orthogonal to the first direction, and wherein the image pixels formed to reconstruct each secondary image are more elongate and closely-packed in the first direction than the second direction.
20. A tangible, non-transitory computer-readable media comprising program instructions stored therein, wherein the program instructions, when executed by one or more processors, cause a holographic system to perform functions comprising:
determining a plurality of secondary images from a primary image, each secondary image formed by sampling pixel values of the primary image at a regular array of sampling positions, wherein a first secondary image is formed using a regular array of first sampling positions and a second secondary image is formed using a regular array of second sampling positions, wherein the second sampling positions are interposed between the first sampling positions in a first direction;
determining a hologram of each secondary image;
causing a display device to display each hologram in rapid succession so as to reconstruct each secondary image from the respective hologram such that a first array of image pixels, substantially corresponding to the primary image, is perceivable, wherein image pixels of the reconstruction of the second secondary image are interposed between image pixels of the reconstruction of the first secondary image in the first direction;
wherein an aperture of the display device is orientated such that it is longer in a second direction than the first direction, wherein the second direction is orthogonal to the first direction, and wherein the image pixels formed to reconstruct each secondary image are more elongate and closely-packed in the first direction than the second direction; and
wherein causing a display device to display each hologram in rapid succession comprises comprising the display device to display each hologram for a second time in rapid succession with a first time so as to reconstruct each secondary image from the respective hologram such that a second array of the image pixels is perceivable.