Method, system, and computer program product for localizing photons and a light source emitting the photons
View Patent ↗Localization methods and methods for localizing a light source using multivariate statistical analysis. In particular, a multi-variate distribution, such as a multi-variate normal distribution, may be used to localize photons originating from a light source and, in particular, may be used to analyze photon position maps acquired by Photon Event Distribution Sampling (PEDS). The multi-variate distribution assigned to each of the photons in the photon position map may be summed to predict a most probable location for the light source.
1. A localization method comprising:
acquiring a first photon position map with a single-photon detector, the first photon position map containing position data for a first plurality of photons originating from a first light source;
assigning with a computer a first probability distribution function to each of the first plurality of photons in the first photon position map originating from the first light source; and
determining with the computer a location for each of the first plurality of photons from the respective first probability distribution function.
2. The localization method of claim 1 further comprising:
summing with the computer the first probability distribution function for each of the first plurality of photons to determine a first location of the first light source.
3. The localization method of claim 2 wherein the first photon position map is acquired over a first time interval, and further comprising:
over a second time interval, acquiring with the single-photon detector a second photon position map containing position data for a second plurality of photons originating from the first light source; and
assigning with the computer a second probability distribution function to each of the second plurality of photons in the second photon position map; and
determining with the computer a location for each of the second plurality of photons from the respective second probability distribution function.
4. The localization method of claim 3 further comprising:
summing with the computer the second probability distribution function for each of the second plurality of photons to determine a second location of the first light source; and
tracking movement with the computer of the first light source based upon a difference between the first and second locations.
5. The localization method of claim 1 further comprising:
constructing with the computer an image of the first light source from the location determined from the first probability distribution function for each of the first plurality of photons.
6. The localization method of claim 1 wherein assigning the first probability distribution function to each of the first plurality of photons in the first photon position map comprises:
assigning with the computer a multi-variate distribution to the spatial coordinates for each photon in the first photon position map to describe the first probability distribution function.
7. The localization method of claim 1 wherein assigning the probability distribution function to each of the first plurality of photons in the first photon position map comprises:
assigning with the computer a multi-variate normal distribution to the spatial coordinates for each photon in the first photon position map to describe the first probability distribution function.
8. The localization method of claim 1 wherein the first photon position map further includes position data for a plurality of photons originating from a second light source and the plurality of photons from the second light source are characterized by a different wavelength than the first plurality of photons from the first light source, and further comprising:
assigning with the computer a second probability distribution function to each of the second plurality of photon in the first photon position map; and
determining with the computer a location for each of the second plurality of photons from the respective second probability distribution function.
9. A system comprising:
a computer including a processor; and
instructions executable using the processor to implement functions comprising acquiring a first photon position map containing position data for a first plurality of photons originating from a first light source, assigning a first probability distribution function to each of the first plurality of photons in the first photon position map originating from the first light source, and determining a location for each of the first plurality of photons from the respective first probability distribution function.
10. The system of claim 9 wherein the functions further comprise summing the first probability distribution function for each of the first plurality of photons to determine a first location of the first light source.
11. The system of claim 9 wherein the first photon position map is acquired over a first time interval, and the functions further comprise, over a second time interval, acquiring a second photon position map containing position data for a second plurality of photons originating from the first light source, assigning a second probability distribution function to each of the second plurality of photons in the second photon position map, and determining a location for each of the second plurality of photons from the respective second probability distribution function.
12. The system of claim 9 wherein the functions further comprise constructing an image of the first light source from the location determined from the first probability distribution function for each of the first plurality of photons.
13. The system of claim 9 wherein the function of assigning the first probability distribution function to each of the first plurality of photons in the first photon position map comprises:
assigning a multi-variate distribution to the spatial coordinates for each photon in the first photon position map to describe the first probability distribution function.
14. The system of claim 9 wherein the first photon position map further includes position data for a plurality of photons originating from a second light source and the plurality of photons from the second light source are characterized by a different wavelength than the first plurality of photons from the first light source, and wherein the functions further comprise:
assigning a second probability distribution function to each of the second plurality of photon in the first photon position map; and
determining a location for each of the second plurality of photons from the respective second probability distribution function.
15. A computer program product comprising:
a non-transitory computer readable storage medium;
first program instructions for acquiring a first photon position map containing position data for a first plurality of photons originating from a first light source;
second program instructions for assigning a first probability distribution function to each of the first plurality of photons in the first photon position map originating from the first light source; and
third program instructions for determining a location for each of the first plurality of photons from the respective first probability distribution function,
wherein the first, second, and third program instructions are stored on the computer readable storage medium.
16. The computer program product of claim 15 further comprising:
fourth program instructions for summing the first probability distribution function for each of the first plurality of photons to determine a first location of the first light source,
wherein the fourth program instructions are stored on the computer readable storage medium.
17. The computer program product of claim 15 wherein the first photon position map is acquired over a first time interval, and further comprising:
fourth program instructions for, over a second time interval, acquiring a second photon position map containing position data for a second plurality of photons originating from the first light source;
fifth program instructions for assigning a second probability distribution function to each of the second plurality of photons in the second photon position map; and
sixth program instructions for determining a location for each of the second plurality of photons from the respective second probability distribution function
wherein the fourth, fifth, and sixth program instructions are stored on the computer readable storage medium.
18. The computer program product of claim 15 further comprising:
fourth program instructions for constructing an image of the first light source from the location determined from the first probability distribution function for each of the first plurality of photons,
wherein the fourth program instructions are stored on the computer readable storage medium.
19. The computer program product of claim 15 wherein the second program instructions comprise:
assigning a multi-variate distribution to the spatial coordinates for each photon in the first photon position map to describe the first probability distribution function.
20. The computer program product of claim 15 wherein the first photon position map further includes position data for a plurality of photons originating from a second light source and the plurality of photons from the second light source are characterized by a different wavelength than the first plurality of photons from the first light source, and further comprising:
fourth program instructions for assigning a second probability distribution function to each of the second plurality of photon in the first photon position map; and
fifth instructions for determining a location for each of the second plurality of photons from the respective second probability distribution function,
wherein the fourth and fifth program instructions are stored on the computer readable storage medium.