Method for timing control of an image sensor
An imaging device having an in vivo CMOS image sensor, at least one illumination source and a controller. The controller controls the illumination source to illuminate for a first period and to be shut off for a subsequent period.
1. A method for in vivo imaging comprising the steps of:
illuminating with an at least one white LED a site in vivo for at least one period of illumination;
providing pixels of an in vivo image sensor with at least one period of illumination during which the pixel circuitry is inactivated and at least one subsequent dark period with the at least one white LED turned off during which integration of dark signals occurs for each pixel for a period of time measured as time elapsed between two consecutive readout pulses applied to the pixel;
successively reading out and then immediately resetting each pixel during the dark period to obtain an image frame; and
eliminating dark signal noise from each image frame.
2. A method according to claim 1 wherein in vivo is in the gastrointestinal tract.
3. The method according to claim 1 wherein the step of providing pixels with at least one period of illumination and at least the one subsequent dark period is performed on all the pixels of the image sensor.
4. The method according to claim 1 wherein the step of providing pixels with at least one period of illumination and at least the one subsequent dark period is performed on 256×256 pixels.
5. The method according to claim 1 wherein the steps are repeated m times to obtain m image frames.
6. The method according to claim 1 further comprising the step of transmitting signals read out from the pixels to an external receiving system.
7. The method according to claim 6 wherein the step of transmitting signals is performed during the subsequent dark period.
8. The method according to claim 7 wherein the step of transmitting signals is preformed at a bandwidth of about 1.35 Megabit per second.
9. The method according to claim 1 wherein eliminating dark signal noise is performed by subtracting a dark frame from an image frame.
10. The method according to claim 1 wherein each pixel of the image sensor is exposed for a same amount of dark signal integration time thereby lowering variation in dark signal noise.