Videostroboscopy of vocal cords with CMOS sensors
The disclosure relates and extends to a light source having a strobing or pulsing sequence suitable for use with a CMOS sensor that does not require, have, or use a global shutter. Instead, the CMOS sensor synchronizes the strobing input with the blanking portion of the sensor readout pattern and disables the strobing during sensor readout, or when the strobing would otherwise leave artifacts in the image. The CMOS sensor freezes its readout during the strobing.
1. A method for providing an image comprising:
continuously determining a frequency of a patient's vocal cords during a videostroboscopy procedure;
strobing light from a light source at a strobing frequency that substantially matches the patient's vocal cord frequency;
receiving a plurality of pulses of light from the light source as strobing input by a CMOS sensor during a pixel readout portion of a readout sequence and during a blanking portion of a readout sequence; and
reading out information obtained from the CMOS sensor to a processor, wherein at least one of the plurality of pulses of light from the light source is suppressed during one or both of the pixel readout portion of the read out sequence and the blanking portion of the readout sequence such that an aggregate amount of illumination which is the sum of the amplitude and the duration of all nonsuppressed pulses for a first blanking period is equal to the aggregate amount of illumination level of in a successive blanking period.
2. The method of claim 1 , wherein the method further comprises eliminating artifacts by disabling the strobing during a CMOS sensor readout period.
3. The method of claim 1 , wherein the method further comprises suppressing the plurality of pulses of light that straddle the pixel readout portion and the first blanking period.
4. The method of claim 1 , wherein the method further comprises suspending each sensor readout frame at least once creating a suspension period, and strobing light during the suspension period.
5. The method of claim 4 , wherein the method further comprises suspending the sensor readout frame a plurality of times per frame, and strobing light during each suspension period.
6. The method of claim 1 , wherein the method further comprises superimposing all images obtained during a readout sequence in relation to corresponding light pulses.
7. The method of claim 1 , wherein the method further comprises applying a digital gain to a subset of rows in a frame in relation to a corresponding light pulse position.
8. The method of claim 1 , wherein the method further comprises applying a plurality of digital gains to a plurality of subsets of rows in a frame in relation to corresponding light pulse positions.
9. The method of claim 1 , wherein the method further comprises applying a dedicated digital gain to all rows in a frame in relation to corresponding light pulse positions.
10. The method of claim 1 , wherein the method further comprises superimposing sensor readout frames corresponding to the plurality of pulses of light to obtain a resultant image.
11. The method of claim 10 , wherein the method further comprises tracking a light deficiency for each row of the CMOS sensor in each superimposed sensor readout frame.
12. The method of claim 11 , wherein the method further comprises applying a digital gain to normalize the resultant image into an artifact-free image.
13. A method for providing an image comprising:
determining a frequency of a patient's vocal cords during a videostroboscopy procedure;
strobing light from a light source at a strobing frequency that substantially matches the patient's vocal cord frequency;
receiving a plurality of pulses of light from the light source as strobing input by a CMOS sensor during a pixel readout portion of a readout sequence and during a blanking portion of a readout sequence;
reading out information obtained from the CMOS sensor to a processor, wherein at least one of the plurality of pulses in the light from the light source is suppressed during one or both of the pixel readout portion of the readout sequence and the blanking portion of the readout sequence such that an aggregate amount of illumination which is the sum of the amplitude and the duration of all nonsuppressed pulses for a first blanking period is equal to the aggregate amount of illumination level of in a successive blanking period;
creating a sensor readout frame for each readout sequence of the CMOS sensor; and
wherein creating the sensor readout frame comprises superimposing a plurality of pulses of light to obtain a resultant image.
14. A method for providing an image comprising:
determining a frequency of a patient's vocal cords during a videostroboscopy procedure;
strobing light from a light source at a frequency that substantially matches the patient's vocal cord frequency;
receiving a plurality of pulses of light from the light source as strobing input by a CMOS sensor during a pixel readout portion of a readout sequence and during a blanking portion of a readout sequence;
reading out information obtained from the CMOS sensor to a processor, wherein at least one of the plurality of pulses of light from the light source is suppressed during one or both of the pixel readout portion of the read out sequence and the blanking portion of the readout sequence such that an aggregate amount of illumination which is the sum of the amplitude and the duration of all nonsuppressed pulses for a first blanking period is equal to the aggregate amount of illumination level of in a successive blanking period;
creating a sensor readout frame for each readout sequence of the CMOS sensor, wherein a light pulse from the light source occurs during a first readout frame of the CMOS sensor;
superimposing sensor readout frames comprising the first readout frame and a subsequent readout frame to obtain a resultant image;
tracking a light deficiency for each row of the CMOS sensor in each superimposed sensor readout frame; and
applying a digital gain to normalize the resultant image into an artifact-free image.