Pulsed illumination in a fluorescence imaging system

1. A system for visualization in a light deficient environment comprising:

an endoscope;

an emitter for emitting a plurality of pulses of electromagnetic radiation for providing illumination in the light-deficient environment;

an image sensor comprising a pixel array that detects electromagnetic radiation and outputs data for generating a plurality of exposure frames; and

a controller in electronic communication with the image sensor and the emitter configured to synchronize timing of the emitter and the image sensor to generate the plurality of exposure frames;

wherein at least a portion of the plurality of pulses of electromagnetic radiation emitted by the emitter comprises a fluorescence excitation wavelength; and

wherein at least a portion of the plurality of exposure frames comprise a fluorescence exposure frame.

2. The system of claim 1 , wherein the pixel array comprises a plurality of pixels, and wherein a sensitivity of each of the plurality of pixels can be adjusted such that the pixel array comprises long exposure pixels and short exposure pixels.

3. The system of claim 1 , wherein at least a portion of the plurality of exposure frames comprises a luminance exposure frame, a red chrominance exposure frame, and a blue chrominance exposure frame, and wherein:

the luminance exposure frame comprises long exposure pixel data and short exposure pixel data; and

the red chrominance exposure frame comprises long exposure pixel data and short exposure pixel data; and

the blue chrominance exposure frame comprises long exposure pixel data and short exposure pixel data.

4. The system of claim 1 , wherein the emitter modulates the pulses of electromagnetic radiation to provide luminance information according to color transformation coefficients that convert light energy from red, green, and blue light energy space to luminance, blue chrominance, and red chrominance light energy space.

5. The system of claim 1 , wherein the emitter modulates the pulses of electromagnetic radiation to provide chrominance information according to color transformation coefficients that convert light energy from red, green, and blue light energy space to luminance, blue chrominance, and red chrominance light energy space.

6. The system of claim 1 , wherein the pulses of electromagnetic radiation are emitted according to a pulsing pattern comprising a luminance pulse, a blue chrominance pulse, a red chrominance pulse, and a fluorescence excitation pulse.

7. The system of claim 1 , wherein the pulses of electromagnetic radiation are emitted according to a pulsing pattern comprising a luminance pulse, a combined blue chrominance and red chrominance pulse, and a fluorescence excitation pulse.

8. The system of claim 1 , wherein the controller is configured to generate image frames comprising data from a plurality of exposure frames, wherein a single image frame comprises data from a luminance exposure frame, a chrominance exposure frame, and the fluorescence exposure frame, wherein the fluorescence exposure frame is sensed by the pixel array in response to an emission of the electromagnetic radiation having the wavelength from about 790 nm to about 815 nm.

9. The system of claim 1 , wherein the image sensor is configured to generate a plurality of exposure frames, wherein each of the plurality of exposure frames corresponds to a pulse of electromagnetic radiation emitted by the emitter.

10. The system of claim 9 , wherein the pixel array of the image sensor senses reflected electromagnetic radiation to generate the plurality of exposure frames during a readout period of the pixel array, wherein the readout period is a duration of time when active pixels in the pixel array are read.

11. The system of claim 1 , wherein the pulses of electromagnetic radiation are emitted according to a pulsing pattern comprising a luminance pulse, a red chrominance pulse, a blue chrominance pulse, and a fluorescence excitation pulse, wherein the luminance pulse is represented in the pulsing pattern twice as often as the red chrominance pulse, the blue chrominance pulse, or the fluorescence excitation pulse.

12. The system of claim 1 , wherein at least a portion of the pulses of electromagnetic radiation emitted by the emitter is a fluorescence excitation wavelength for fluorescing a reagent, wherein the fluorescence excitation wavelength comprises the electromagnetic radiation having the wavelength from about 790 nm to about 815 nm.

13. The system of claim 1 , wherein the emitter is configured to emit, during a pulse duration, a plurality of sub-pulses of electromagnetic radiation having a sub-duration shorter than the pulse duration.

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

15. The system of claim 1 , wherein at least a portion of the pulses of electromagnetic radiation emitted by the emitter is a fluorescence excitation emission that results in the fluorescence exposure frame created by the image sensor, and wherein the controller is configured to provide the fluorescence exposure frame to a corresponding system that determines a location of a tissue structure within a scene based on the fluorescence exposure frame.

16. The system of claim 15 , wherein the fluorescence excitation emission comprises one or more of:

electromagnetic radiation having a wavelength from about 770 nm to about 790 nm; or

the electromagnetic radiation having the wavelength from about 790 nm to about 815 nm.

17. The system of claim 15 , wherein the controller is further configured to:

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

generate an overlay frame comprising the location of the tissue structure; and

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

18. The system of claim 17 , wherein the tissue structure comprises one or more of a nerve, a ureter, a blood vessel, an artery, a blood flow, or a tumor.

19. The system of claim 1 , wherein the controller is configured to synchronize timing of the pulses of electromagnetic radiation during a blanking period of the image sensor, wherein the blanking period 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.

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

21. The system of claim 1 , wherein the image sensor comprises a first image sensor and a second image sensor such that the image sensor can generate a three-dimensional image.

22. The system of claim 1 , wherein the emitter is configured to emit a sequence of pulses of electromagnetic radiation repeatedly sufficient for generating a video stream comprising a plurality of image frames, wherein each image frame in the video stream comprises data from a plurality of exposure frames, and wherein each of the exposure frames corresponds to a pulse of electromagnetic radiation.

23. The system of claim 1 , wherein the pulses of electromagnetic radiation are emitted in a pattern of varying wavelengths of electromagnetic radiation, and wherein the emitter repeats the pattern of varying wavelengths of electromagnetic radiation.

24. The system of claim 1 , wherein at least a portion of the pulses of electromagnetic radiation comprise a red wavelength, a green wavelength, a blue wavelength, and a fluorescence excitation wavelength such that reflected electromagnetic radiation sensed by the pixel array corresponding to each of the red wavelength, the green wavelength, the blue wavelength, and the fluorescence excitation wavelength can be processed to generate a Red-Green-Blue (RGB) image frame comprising an overlay of fluorescence imaging data, wherein the fluorescence excitation wavelength of electromagnetic radiation comprises the electromagnetic radiation having the wavelength from about 790 nm to about 815 nm.

25. The system of claim 1 , wherein at least a portion of the pulses of electromagnetic radiation comprise a luminance emission, a red chrominance emission, a blue chrominance emission, and a fluorescence excitation emission such that reflected electromagnetic radiation sensed by the pixel array corresponding to each of the luminance emission, the red chrominance emission, the blue chrominance emission, and the fluorescence excitation emission can be processed to generate a YCbCr image frame comprising an overlay of fluorescence imaging data, wherein the fluorescence excitation emission of electromagnetic radiation comprises the electromagnetic radiation having the wavelength from about 790 nm to about 815 nm.

26. The system of claim 1 , further comprising a filter that filters electromagnetic radiation having a wavelength from about 790 nm to about 815 nm.