Temporal modeling of phase modulators in multi-modulation projection
A novel projection system includes a light source, a phase modulator, an amplitude modulator, and a controller having temporal lightfield simulation capabilities. The phase modulator spatially modulates a lightfield from the light source to generate an intermediate image on the amplitude modulator. The amplitude modulator spatially modulates the intermediate image to form a final image. The controller models the phase state of the phase modulator during transitions between phase modulator frames and generates lightfield simulations of the intermediate image during the transition. The controller utilizes the lightfield simulations to generate and provide sets of amplitude drive values to the amplitude modulator at a faster rate than that at which the phase modulator is capable of switching.
1. A controller for controlling a projection system, said controller comprising:
a processing unit configured to execute code;
an interface coupled to receive a first frame of image and a second frame of image data; and
memory electrically coupled to store data and said code, said data and said code including
a phase drive module configured to
generate a first set of phase drive values for driving a phase-modulating spatial light modulator (SLM), said first set of phase drive values being based at least in part on said first frame of image data,
generate a second set of phase drive values for driving said phase-modulating SLM, said second set of phase drive values being based at least in part on said second frame of image data,
drive said phase-modulating SLM with said first set of phase drive values during a first time period, and
drive said phase-modulating SLM with said second set of phase drive values during a second time period,
a temporal lightfield simulation module configured to
model transitional states of said phase-modulating SLM during said second time period, said transitional states being based at least in part on said first phase drive values and said second phase drive values, and
generate a set of lightfield simulations of lightfields generated by said phase-modulating SLM and incident on an amplitude-modulating SLM, a first subset of said set of lightfield simulations corresponding to said first set of phase drive values, a second subset of said set of lightfield simulations corresponding to said second set of phase drive values, and a third subset of said set of lightfield simulations corresponding to one or more of said transitional states of said phase-modulating SLM, and
an amplitude drive module configured to
generate sets of amplitude drive values for driving said amplitude-modulating SLM, each of said sets of amplitude drive values corresponding to one of said set of lightfield simulations, and
drive said amplitude SLM with said sets of amplitude drive values.
2. The controller of claim 1 , wherein said phase drive module is configured to:
utilize said first set of phase drive values as an initial approximation of said second set of phase drive values when generating said second set of phase drive values; and
alter said initial approximation of said second set of phase drive values based on said third frame of image data.
3. The controller of claim 1 , wherein:
said phase-modulating SLM comprises a plurality of pixels; and
said temporal lightfield simulation module is configured to model individual transitional states of pixels of said plurality of pixels.
4. The controller of claim 3 , wherein:
said phase drive module is configured to assert a first set of voltages across said plurality of pixels, each voltage of said first set of voltages based on said first set of phase drive values;
said phase drive module is configured to assert a second set of voltages across said plurality of pixels, each voltage of said second set of voltages based on said second set of phase drive values; and
said temporal lightfield simulation module is configured to determine an individual transition of each pixel of said plurality of pixels from a corresponding voltage of said first set of voltages to a corresponding voltage of said second set of voltages.
5. The controller of claim 4 , wherein said temporal lightfield simulation module is configured to determine a transitional state of each pixel of said plurality of pixels at a particular time during said individual transition.
6. The controller of claim 4 , wherein said temporal lightfield simulation module is configured to determine an average transitional state of each of said plurality of pixels over a period of time during said individual transition.
7. The controller of claim 1 , wherein said temporal lightfield simulation module is configured to model transitional states of said phase-modulating SLM based at least in part on a physical characteristic of said phase-modulating SLM.
8. The controller of claim 1 , wherein said temporal lightfield simulation module is configured to model transitional states of said phase-modulating SLM based at least in part on a physical characteristic of a liquid crystal layer of said phase-modulating SLM.
9. The controller of claim 1 , wherein said temporal lightfield simulation module is configured to model transitional states of said phase-modulating SLM based at least in part on a characteristic of a lightfield incident on said phase-modulating SLM.
10. The controller of claim 9 , wherein said temporal lightfield simulation module is configured to model transitional states of said phase modulating SLM based at least in part on a history of said lightfield.
11. The controller of claim 1 , wherein said temporal lightfield simulation module models each pixel of a plurality of pixels of said phase-modulating SLM as a source of spherical waves having a phase delay determined at least in part by a corresponding one of said transitional states.
12. The controller of claim 1 , wherein said temporal lightfield simulation module models each pixel of a plurality of pixels of said phase-modulating SLM as an origin point of a light ray having an angle with respect to a surface of said phase-modulating SLM determined at least in part by a corresponding one of said transitional states.
13. In a projection system, a method for generating images, said method comprising:
receiving (n) frames of image data;
generating (m) frames of phase drive values, each frame of phase drive values being based at least in part on an associated frame of said image data and causing a phase-modulating spatial light modulator (SLM) to be in an associated phase state to generate a lightfield corresponding to said associated frame of image data;
determining (p) transitional phase states of said phase-modulating SLM where p>0, each of said transitional phase states indicative of a lightfield generated by said phase-modulating SLM during a transition between sequential ones of said phase states associated with said phase drive values;
generating a set of lightfield simulations based on said phase drive values and said transitional phase states, each of said lightfield simulations being indicative of a lightfield generated by said phase-modulating SLM and incident on an amplitude-modulating SLM; and
generating a set of frames of amplitude drive values based on said set of lightfield simulations and said frames of image data.
14. The method of claim 13 , wherein m+p=n.
15. The method of claim 13 , wherein m/p=1.
16. The method of claim 13 , wherein m/p<1.
17. The method of claim 13 , wherein m=n.
18. The method of claim 17 , wherein p=n.
19. The method of claim 17 , wherein p/m>1.
20. The method of claim 17 , wherein p/m=3.