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1. (WO2017091283) SYSTEMS AND METHODS FOR REAL-TIME LASER DOPPLER IMAGING
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CLAIMS

What is claimed is:

1. A system, comprising:

an optical modulator;

a local oscillator source configured to provide a reference frequency signal to the optical modulator;

an offset source configured to provide an offset frequency signal;

a mixer configured to provide a heterodyne signal based on the reference frequency signal and the offset frequency signal;

a light source optically coupled to the optical modulator, wherein the light source is operable to emit light so as to illuminate a sample with at least a first portion of the emitted light and illuminate the optical modulator with at least a second portion of the emitted light, wherein the optical modulator is configured to controllably modulate at least the second portion of the emitted light based on the reference frequency signal so as to provide modulated light;

an image sensor optically coupled to the sample and the optical modulator, such that the modulated light illuminates the image sensor, wherein the image sensor comprises a plurality of detector elements, wherein each detector element of the plurahty of detector elements has a gain input, wherein the gain input is coupled to the mixer such that the gain input of each detector element is modulated based on the heterodyne signal; and a controller comprising at least one processor, wherein the controller is programmed to cany out operations, the operations comprising:

adjusting a frequency of the heterodyne signal;

while adjusting the the frequency of the heterodyne signal, receiving information from the image sensor; and

determining a movement of a portion of the sample based on the received information.

2. The system of claim 1, wherein adjusting the frequency of the heterodyne signal comprises adjusting the offset source such that the offset frequency signal is varied within a predetermined range of offset frequencies.

3. The system of claim 1 , wherein the optical modulator comprises at least one of: an acousto-optic modulator or an electro-optic modulator.

4. The system of claim 1 , wherein the light source comprises a single mode laser.

5. The system of claim 1, wherein the light source comprises a plurality of lasers.

6. The system of claim 1, wherein the image sensor comprises a gain-modulated image sensor.

7. The system of claim 1, wherein the image sensor comprises at least one of: an avalanche photodiode (APD), a photomultiplier tube (PMT), a complementary metal oxide semiconductor (CMOS) detector, or a charge-coupled device (CCD).

8. The system of claim I, wherein determining a movement of a portion of the sample based on the received information comprises determining a fluid flow in the portion of the sample.

9. The system of claim 8, wherein determining the fluid flow in the portion of the sample comprises determining a flow rate of the fluid flow in the portion of the sample.

10. The system of claim 9, wherein the operations further comprise determining a flow map for the sample, wherein the flow map includes a respective flow rate for each of a plurality of portions of the sample.

11. The system of claim 1, wherein the reference frequency signal is between 1 and 100 MHz, and wherein the offset frequency signal is between 0 to 5 MHz.

12. The system of claim 1, wherein the received information comprises information indicative of scattering interactions between the first portion of the emitted light and the portion of the sample.

13. The system of claim 1 , wherein at least a portion of the system is incorporated into an endoscope.

14. A method comprising:

causing a light source to emit light so as to illuminate a sample with at least a first portion of the emitted light and illuminate an optical modulator with at least a second portion of the emitted light, wherein the optical modulator is configured to controllably modulate at least the second portion of the emitted light based on a reference frequency signal so as to provide modulated light;

adjusting an offset source, wherein the offset source is configured to provide an offset frequency signal, wherein adjusting the offset source comprises varying the offset frequency signal within a predetermined range of offset frequencies;

while adjusting the offset source, receiving information from an image sensor, wherein the image sensor is optically coupled to the sample and the optical modulator, such that the modulated light illuminates the image sensor, wherein the image sensor comprises a plurality of detector elements, wherein each detector element of the plurality of detector elements has a gain input, wherein the gain input is coupled to a mixer, wherein the mixer is configured to provide a heterodyne signal based on the reference frequency signal and the offset frequency signal, and wherein the gain input of each detector element is modulated based on the heterodyne signal; and

determining a movement of a portion of the sample based on the received information.

15. The method of claim 14, wherein the optical modulator comprises at least one of: an acousto-optic modulator or an electro-optic modulator.

16. The method of claim 14, wherein the light source comprises a single mode laser.

17. The method of claim 14, wherein the light source comprises a plurality of lasers.

18. The method of claim 14, wherein the image sensor comprises at least one of: an avalanche photodiode (APD), a pliotomultiplier tube (PMT), a complementary metal oxide semiconductor (CMOS) detector, or a charge-coupled device (CCD).

19. The method of claim 14, wherein determining the movement of the portion of the sample based on the received information comprises determining a fluid flow in the portion of the sample.

20. The method of claim 19, wherein determining the fluid flow in the portion of the sample comprises determining a flow rate of the fluid flow in the portion of the sample.

21. The method of claim 20, further comprising determining a flow map for the sample, wherein the flow map includes a respective flow rate for each of a plurality of portions of the sample.

22. The method of claim 14, wherein the reference frequency signal is between 1 and 100 MHz, and wherein the offset frequency signal is between 0 to 5 MHz

23. The method of claim 14, wherein the received information comprises information indicative of scattering interactions between the first portion of the emitted light and the portion of the sample.