Methods and devices for improving dynamic range in image sensors
View Patent ↗Methods and devices for improving dynamic range in image sensors are disclosed. An image sensing device comprises an image sensor having a plurality of rows of pixels, and a controller for controlling the exposure of each row of pixels. The controller is programmed to perform a shutter operation for one of the plurality of rows of pixels, and to sample the one of the plurality of rows after a predetermined duration following the performance of the shutter operation. The predetermined duration is different from a multiple of a row time period of the image sensing device.
1. A method for sensing images with an image sensing device, the image sensing device comprising an image sensor having a plurality of rows of pixels, the method comprising:
performing a shutter operation for one of the plurality of rows of pixels;
sampling the one of the plurality of rows after a predetermined duration following the performance of the shutter operation, the predetermined duration being different from a multiple of a row time period of the image sensing device, wherein the performing step comprises turning the reset gate and the transfer gate on and off for each pixel in the row, wherein the plurality of rows of pixels comprise a plurality of shared floating diffusions, wherein the plurality of shared floating diffusions are shared across multiple rows, and wherein the sampling step comprises sequentially turning on the transfer gates for a first row of pixels of a shared floating diffusion, turning on the row-select gate for the first row, and then turning on the reset gate for the shared floating diffusion prior to turning on a transfer gate for a second row of pixels of the shared floating diffusion.
2. The method of claim 1 , wherein the predetermined duration is less than one row time period.
3. The method of claim 1 , wherein the predetermined duration is greater than one row time period.
4. An image sensing device comprising:
an image sensor having a plurality of rows of pixels;
a controller for controlling the exposure of each row of pixels, the controller programmed to:
perform a shutter operation for one of the plurality of rows of pixels;
sample the one of the plurality of rows after a predetermined duration following the performance of the shutter operation, the predetermined duration being different from a multiple of a row time period of the image sensing device, wherein the controller performs the shutter operation by turning the reset gate and the transfer gate on and off for each pixel in the row, wherein the plurality of rows of pixels comprise a plurality of shared floating diffusions, wherein the plurality of shared floating diffusions are shared across multiple rows, and wherein the controller samples the one of the plurality of rows by sequentially turning on the transfer gates for a first row of pixels of a shared floating diffusion, turning on the row-select gate for the first row, and then turning on the reset gate for the shared floating diffusion prior to turning on a transfer gate for a second row of pixels of the shared floating diffusion.
5. The image sensing device of claim 4 , wherein the predetermined duration is less than one row time period.
6. The image sensing device of claim 4 , wherein the predetermined duration is greater than one row time period.