Systems and methods for mitigating artifacts in medical imaging
An exemplary method of imaging tissue of a subject using a rolling shutter imager to provide a video stream comprises: sequentially resetting a plurality of rows of pixels of the rolling shutter imager from a first row to a last row; transitioning a liquid crystal shutter from a closed state to an open state; after the liquid crystal shutter is transitioned into the open state and after resetting the last row, illuminating the tissue of the subject with an illumination light for an illumination period to accumulate charge at the plurality of rows of pixels, and after the illumination period ends, sequentially reading the accumulated charge at the rows of pixels from the first row to the last row; generating an image frame from the sequentially read accumulated charge at the plurality of rows of pixels; and adding the image frame to the video stream.
1. A method of imaging tissue of a subject using a rolling shutter imager to provide a video stream, the method comprising:
sequentially resetting a plurality of rows of pixels of the rolling shutter imager from a first row to a last row;
transitioning a liquid crystal shutter from a closed state to an open state;
after the liquid crystal shutter is transitioned into the open state and after resetting the last row, illuminating the tissue of the subject with an illumination light for an illumination period to accumulate charge at the plurality of rows of pixels, and
after the illumination period ends, sequentially reading the accumulated charge at the rows of pixels from the first row to the last row;
generating an image frame from the sequentially read accumulated charge at the plurality of rows of pixels; and
adding the image frame to the video stream.
2. The method of claim 1 , wherein the illumination period is at least a portion of the time period between when the last row is reset and when the first row is read.
3. The method of claim 2 , wherein the illumination period starts when the last row is reset.
4. The method of claim 1 , wherein the plurality of rows of pixels is exposed for the same period of time to generate the image.
5. The method of claim 1 , further comprising: after the end of the illumination period, starting transitioning the liquid crystal shutter from the open state to the closed state.
6. The method of claim 1 , further comprising: at the end of the illumination period, starting transitioning the liquid crystal shutter from the open state to the closed state.
7. The method of claim 1 , further comprising: before the end of the illumination period, starting transitioning the liquid crystal shutter from the open state to the closed state.
8. The method of claim 1 , wherein the liquid crystal shutter is opened or closed using a timer device based on a vertical sync pulse.
9. The method of claim 1 , wherein the liquid crystal shutter is opened or closed based on one or more characteristics of an imaged scene.
10. The method of claim 9 , wherein the one or more characteristics of the imaged scene comprise brightness and/or modality of the imaged scene.
11. The method of claim 1 , wherein the illumination light is generated by at least one LED.
12. The method of claim 1 , wherein the rolling shutter imager is part of an endoscopic imager.
13. The method of claim 1 , wherein the rolling shutter imager is part of a flexible and/or chip-on-tip scope.
14. A system of imaging tissue of a subject to provide a video stream, the system comprising:
an illumination source; and
an imaging apparatus that comprises a rolling shutter imager, the imaging apparatus being configured for:
sequentially resetting a plurality of rows of pixels of the rolling shutter imager from a first row to a last row;
transitioning a liquid crystal shutter from a closed state to an open state;
after the liquid crystal shutter is transitioned into the open state and after resetting the last row, illuminating the tissue of the subject with the illumination source for an illumination period to accumulate charge at the plurality of rows of pixels, and
after the illumination period ends, sequentially reading the accumulated charge at the rows of pixels from the first row to the last row;
generating an image frame from the sequentially read accumulated charge at the plurality of rows of pixels; and
adding the image frame to the video stream.
15. The system of claim 14 , wherein the illumination period is at least a portion of the time period between when the last row is reset and when the first row is read.
16. The system of claim 15 , wherein the illumination period starts when the last row is reset.
17. The system of claim 14 , wherein the plurality of rows of pixels is exposed for the same period of time to generate the image.
18. The system of claim 14 , wherein the imaging apparatus is further configured for: after the end of the illumination period, starting transitioning the liquid crystal shutter from the open state to the closed state.
19. The system of claim 14 , wherein the imaging apparatus is further configured for: at the end of the illumination period, starting transitioning the liquid crystal shutter from the open state to the closed state.
20. The system of claim 14 , wherein the imaging apparatus is further configured for: before the end of the illumination period, starting transitioning the liquid crystal shutter from the open state to the closed state.
21. The system of claim 14 , wherein the liquid crystal shutter is opened or closed using a timer device based on a vertical sync pulse.
22. The system of claim 14 , wherein the liquid crystal shutter is opened or closed based on one or more characteristics of an imaged scene.
23. The system of claim 22 , wherein the one or more characteristics of the imaged scene comprise brightness and/or modality of the imaged scene.
24. The system of claim 14 , wherein the illumination source comprises at least one LED.
25. The system of claim 14 , wherein the rolling shutter imager is part of an endoscopic imager.
26. The system of claim 14 , wherein the rolling shutter imager is part of a flexible and/or chip-on-tip scope.