METHOD FOR GENERATING A HEAD UP DISPLAY FOR AN AIRCRAFT USING VIDEO HOLOGRAMS IN REAL TIME WITH THE HELP OF SUB- HOLOGRAMS

• US 20180259905A1
• Filed: 05/14/2018
• Published: 09/13/2018
• Est. Priority Date: 09/01/2006
• Status: Active Grant

• Current Assignee: SeeReal Technologies S.A.
• Original Assignee: SeeReal Technologies S.A.
• Inventors: ZSCHAU, Enrico, SCHWERDTNER, Armin, KROLL, Bo, SCHWERDTNER, Alexander
• Granted Patent: US 10,678,188 B2
• Time in Patent Office: Days
• CPC Class Codes: G03H 1/0808 Methods of numerical synthesis, e.g. coherent ray tracing [CRT], diffraction specific
• CPC Class Codes: G03H 1/2294 Addressing the hologram to an active spatial light modulator
• CPC Class Codes: G03H 2001/0833 Look up table
• CPC Class Codes: G03H 2210/30 3D object
• CPC Class Codes: G03H 2210/452 into points
• CPC Class Codes: G03H 2226/05 Means for tracking the observer

Abstract

A method for generating video holograms in real time for a holographic playback device comprising at least one light modulator means, into which a scene divided into object points is encoded as an entire hologram and can be seen as a reconstruction from a visibility region, which is located within a periodicity interval of the reconstruction of the video hologram, the visibility region defining a subhologram together with each object point of the scene to be reconstructed, and the entire hologram being generated from a superposition of contributions of subholograms, is characterized in that for each object point the contributions of the subholograms in the entire reconstruction of the scene can be determined from at least one look-up table.

Claims

1. An aircraft, having a cockpit for at least one person, the cockpit comprising at least one display being embodied in the form of a head up display, the head up display is adapted to display image information representing at least one of two-dimensional information and three-dimensional information, wherein the head up display is configured such that the two-dimensional information or the three-dimensional information is viewable by the person in the cockpit of the aircraft.

2. The aircraft according to claim 1, wherein the head up display comprises a light source and at least one optical element, wherein the image information is encoded into at least one light modulator means of the at least one head up display in the cockpit, and wherein the cockpit comprises a screen means being an optical element on to which light coming from the light modulator means is projected.

3. A method for generating the image information representing the two-dimensional information or the three-dimensional information according to claim 2 in real time for the at least one head up display in the cockpit of the aircraft, the method comprising the steps of:

encoding hologram values of an entire hologram in the at least one light modulator means, where the entire hologram represents a scene;

dividing the scene into object points, where the scene is observable as a reconstruction from a visibility region which is located at an eye of an observer where position and size of a sub-hologram depend on the position of the visibility region and on the position of one of the object points of the scene; and

forming the hologram values of the entire hologram using a mathematical superimposition of contributions of hologram values of sub-holograms;

where the contributions of the hologram values of the sub-holograms to the hologram values of the entire hologram representing the scene are retrievable from at least one look-up table for each object point and where the look-up table comprises the hologram values of the sub-holograms.

4. The method according to claim 3 where the position and viewing direction of an observer define a view of the scene and where the observer is assigned with at least one visibility region, which lies near the eyes in an observer plane, where the scene to be reconstructed is three-dimensionally decomposed into visible object points and which comprises the following process steps:

finding the position and size of the sub-hologram for each visible object point,

determination of the contributions of the corresponding sub-hologram from at least one look-up table,

repetition of these two steps for all object points, where the hologram values of the sub-holograms are mathematically superimposed so to form an entire hologram for the reconstruction of the entire scene.

5. The method according to claim 3 where at least one of hologram values of the sub-holograms and the entire hologram are modulated with brightness values or where at least one of hologram values of the sub-holograms and the entire hologram are modulated with colour values.

6. The method according to claim 5 where at least one of hologram values of the sub-holograms and the entire hologram are modulated with brightness values from at least one look-up table or where at least one of hologram values of the sub-holograms and the entire hologram are modulated with colour values from at least one look-up table.

7. The method according to claim 3 where correction values are added to the hologram values of the sub-holograms and/or the entire hologram.

8. The method according to claim 3 where the position of the sub-hologram is determined such that the centre of the sub-hologram lies on the straight line through the object point to be reconstructed and the centre of the visibility region.

9. The method according to claim 8 where the size of the sub-hologram is determined by tracing back the visibility region through the object point to the light modulator means.

10. The method according to claim 3 where for colour representation the hologram values of the sub-holograms for primary colours can be retrieved from respective look-up tables.

11. The method according to claim 3 where hologram values are converted into pixel values of the light modulator means.

12. The method according to claim 11 where the hologram values are converted into Burckhardt components or components for a two-phase encoding.

13. The method according to claim 3 for a holographic display device with a screen means, where the screen means is an optical element on to which a hologram or wave front of the scene encoded on the light modulator means is projected.

14. The method according to claim 13 where the optical element of the display device is a lens or mirror.

15. The method according to claim 3 where the hologram values of the sub-hologram of an object point are determined by computationally propagating the wave front which is emitted by the object point into the visibility region.

16. The method according to claim 3 where the look-up table is generated by determining the hologram values of the sub-hologram for each possible object point in a defined space by computationally propagating the wave front which is emitted by the object point into the visibility region and by performing a mathematical back-transformation of the wave front from the visibility region into the hologram plane where the light modulator means is situated.

18. The method according to claim 3 where the look-up table is generated by determining the hologram values of the sub-hologram for each possible object point in a defined space with the help of optimisation or approximation methods.

19. A holographic display device comprising at least one light modulator means, wherein the holographic display device is adapted to carry out the method according to claim 3.