Speckle removal in a pulsed fluorescence imaging system

1. A system for endoscopic visualization of a light deficient environment, the system comprising:

a light source that emits pulses of light according to a variable pulse cycle, wherein the light source comprises a plurality of electromagnetic radiation sources comprising:

an excitation source that emits electromagnetic radiation within a range from 750 nm to 835 nm; and

a visible source that emits electromagnetic radiation within a visible waveband of the electromagnetic spectrum;

a fiber optic bundle for communicating the pulses of light from the light source;

an image sensor comprising a pixel array that accumulates electromagnetic radiation and reads out a plurality of frames according to a sensor cycle comprising a plurality of blanking periods and a plurality of readout periods; and

a controller that synchronizes operations of the light source and the image sensor by synchronizing timing of the variable pulse cycle of the light source with timing of the sensor cycle of the image sensor, wherein synchronizing the timing comprises:

optimizing the variable pulse cycle such that the light source pulses only the visible source during a blanking period that immediately precedes the image sensor reading out a color frame; and

optimizing the variable pulse cycle such that the light source pulses only the excitation source during a blanking period that immediately precedes the image sensor reading out a fluorescence frame;

wherein the light deficient environment is illuminated at a threshold oscillation frequency to reduce speckle in the plurality of frames read out by the image sensor; and

wherein the plurality of frames is processed to render a video stream comprising a plurality of overlay frames, and wherein at least one overlay frame of the plurality of overlay frames comprises each of:

an overlay identifying a target structure, wherein the overlay is generated by a corresponding system trained to identify the target structure based on data from one or more of a plurality of fluorescence frames; and

dimensional data comprising one or more of a three-dimensional surface topology, a distance between objects, or a dimension of an object within the scene.

2. The system of claim 1 , further comprising a vibrating mechanism that vibrates according to the threshold oscillation frequency, wherein the vibrating mechanism comprises one or more of a mechanical motor, a piezoelectric crystal, an oscillator, or a resonator component.

3. The system of claim 2 , wherein the controller is further in electronic communication with the vibrating mechanism and is further configured to control operation of the vibrating mechanism such that coherency of the pulses of light is reduced.

4. The system of claim 3 , wherein the light source is a coherent light source that emits pulses of coherent light, and wherein the controller is further configured to control the operation of the vibrating mechanism such that speckle caused at least in part by the coherency of the pulses of coherent light is not visible to a user in an exposure frame generated by the image sensor.

5. The system of claim 1 , further comprising:

a vibrating mechanism attached to the fiber optic bundle;

a sleeve for coupling a first fiber optic portion of the fiber optic bundle to a second fiber optic portion of the fiber optic bundle; and

a housing of the vibrating mechanism configured to house a vibrating device, wherein the vibrating device comprises one or more of a mechanical motor, a piezoelectric crystal, an oscillator, or a resonator component;

wherein the housing of the vibrating mechanism is attached to the sleeve.

6. The system of claim 5 , wherein the vibrating mechanism is the only vibrating mechanism attached to the fiber optic bundle, and wherein the vibrating mechanism vibrates each of the first fiber optic portion and the second fiber optic portion.

7. The system of claim 1 , further comprising a vibrating mechanism configured to vibrate the fiber optic bundle such that at least one pulse of light of the pulses of light transmitted on the fiber optic bundle loses coherency momentarily as the geometry of the path travelled by the pulse of light is changed by vibration of the vibrating mechanism.

8. The system of claim 1 , wherein each of the plurality of electromagnetic radiation sources of the light source is a laser bundle comprising a plurality of laser units, and wherein:

the visible source comprises one or more visible laser bundles that each emit electromagnetic radiation within the visible waveband; and

the excitation source comprises one or more excitation laser bundles that each emit electromagnetic radiation within the range from 750 nm to 835 nm.

9. The system of claim 8 , wherein at least a portion of the one or more excitation laser bundles is finely tuned to emit electromagnetic radiation within a wavelength band from 770 nm to 795 nm.

10. The system of claim 1 , further comprising a vibrating mechanism attached to the fiber optic bundle, and wherein:

the vibrating mechanism introduces a vibration stimulus to the fiber optic bundle to cause a series of changes to the path geometry of the fiber optic bundle; and

wherein the series of changes to the path geometry are performed at a high frequency such that an observable speckle pattern in an exposure frame sensed by the pixel array of the image sensor is removed.

11. The system of claim 1 , wherein the plurality of frames comprises:

the plurality of color frames, wherein the pixel array reads out each of the plurality of color frames in response to the light source cycling on the visible source; and

the plurality of fluorescence frames, wherein the pixel array reads out each of the plurality of fluorescence frames in response to accumulating a fluorescence relaxation wavelength emitted by a tissue or reagent.

12. The system of claim 1 , wherein the controller synchronizes the variable pulse cycle and the sensor cycle such that the image sensor accumulates electromagnetic radiation during a blanking period when the image sensor is not reading out any active pixels; and

the image sensor reads out data during a readout period when the light source is cycled off.

13. The system of claim 1 , wherein the excitation source is tuned to elicit a fluorescence response from a tissue or reagent.

14. The system of claim 1 , wherein the image sensor asynchronously reads out data for the plurality of color frames and the plurality of fluorescence frames.

15. The system of claim 1 , wherein one or more of the pulses of light emitted by the light source comprises electromagnetic radiation emitted at two or more wavelengths simultaneously as a single pulse or a single sub-pulse.

16. The system of claim 1 , wherein the controller is configured to provide the plurality of fluorescence frames to a corresponding system trained to identify and locate the target structure within the scene.

17. The system of claim 16 , wherein the excitation source is tuned to emit a wavelength of electromagnetic radiation that elicits a fluorescence response from a reagent within the scene, and wherein the reagent is configured to attach to the target structure.

18. The system of claim 16 , wherein the controller is further configured to:

receive the location of the target structure from the corresponding system;

generate the overlay highlighting the location of the target structure; and

combine the overlay with a color image frame depicting the scene to indicate the location of the target structure within the scene.

19. The system of claim 18 , wherein the target structure comprises one or more of a nerve, a ureter, a blood vessel, an artery, a blood flow, or a tumor.

20. The system of claim 1 , wherein the controller is configured to synchronize timing of the pulses of light during a blanking period of the plurality of blanking periods of the sensor cycle, wherein the plurality of blanking periods each corresponds to a time between a readout of a last row of active pixels in the pixel array and a beginning of a next subsequent readout of active pixels in the pixel array.

21. The system of claim 1 , wherein two or more pulses of light emitted by the light source result in two or more instances of reflected electromagnetic radiation that are sensed by the pixel array to generate two or more frames that are combined to form an overlay frame.

22. The system of claim 1 , wherein the image sensor comprises a first image sensor and a second image sensor, and wherein simultaneous frames output by the first image sensor and the second image sensor are assessed to calculate the dimensional data.

23. The system of claim 1 , wherein the light source further comprises a laser mapping source configured to pulse electromagnetic radiation in a laser mapping pattern;

wherein the image sensor reads out a laser mapping frame in response to the light source actuating the laser mapping source; and

wherein the laser mapping frame comprises data for calculating the dimensional data.

24. The system of claim 1 , wherein the variable pulse cycle is adjustable based on user input.

25. The system of claim 1 , wherein the visible source comprises one or more of a white light source, a red light source, a green light source, or a blue light source.

26. The system of claim 1 , wherein the pixel array separately reads out a luminance-only frame, a red chrominance-only frame, and a blue chrominance-only frame, and wherein the luminance-only frame, the red chrominance-only frame, and the blue chrominance-only frame are combined to generate a YCbCr image frame that is converted to color image data.

27. The system of claim 1 , further comprising a filter that filters electromagnetic radiation having a wavelength from about 770 nm to about 795 nm.