Images with high speed digital frame transfer and frame processing
View Patent ↗A digital frame transfer imager having an image sensor and frame memory in the same chip. The image sensor has an integrated memory controller for controlling transfers of data between the sensor and the memory array. The imager utilizes a rolling shutter and multiple groups of analog-to-digital processing circuitry to readout data from the sensor and to output digital images substantially free from image smear, kT/C noise and other unwanted image artifacts.
1. An imager component comprising:
an image sensor having a pixel array organized into rows and columns, the array configured to capture an image, the sensor further comprising an output bus configured to output digital data corresponding to the captured image; and
a frame memory connected to the image sensor via at least one bus,
said image sensor comprising a memory controller configured to control data transfers between the frame memory and the image sensor;
wherein the image sensor further comprises:
column parallel analog readout circuitry connected to the columns, the column parallel analog readout circuitry converting signals associated with the captured image into the digital data; and
a plurality of pixel line buffer memories, each line buffer memory being connected to and associated with a group of columns and storing a respective portion of the digital data associated with the respective group of columns, the line buffer memories configured to store the digital data from the column parallel analog readout circuitry during the readout operation,
wherein the controller causes all of the digital data to be sequentially stored in the frame memory.
2. The imager component of claim 1 , wherein the image sensor is operated using a rolling shutter.
3. The imager component of claim 1 , wherein the frame memory comprises a plurality of memory devices, each device being configured to store a respective portion of the digital data input from the line buffer memories and wherein a number of frame memory devices and line buffer memories are the same.
4. The imager component of claim 1 , wherein the column parallel analog readout circuitry comprises at least one analog-to-digital conversion circuit per column in the array, each analog-to-digital conversion circuit being operated simultaneously during a readout operation.
5. An imager component comprising:
an image sensor having a pixel array organized into rows and columns, the array configured to capture an image, the sensor further comprising an output bus configured to output digital data corresponding to the captured image; and
a frame memory connected to the image sensor via at least one bus,
said image sensor comprising a memory controller configured to control data transfers between the frame memory and the image sensor;
wherein the image sensor further comprises:
column parallel analog readout circuitry connected to the columns, the column parallel analog readout circuitry converting signals associated with the captured image into the digital data;
a plurality of pixel line buffer memories, each line buffer memory being connected to and associated with a group of columns and storing a respective portion of the digital data associated with the respective group of columns, the line buffer memories configured to store the digital data from the column parallel analog readout circuitry during the readout operation; and
digital processing circuitry connected between the pixel line buffer memories and the frame memory for processing the digital data according to an operating mode of the image sensor.
6. The imager component of claim 5 , wherein the digital processing circuitry comprises:
circuitry for performing one of averaging, summation or subtraction on digital data input from the frame memory; and
pixel output line buffer memory for sequentially storing the processed digital data before the data is output over the output bus.
7. The imager component of claim 5 , wherein the digital processing circuitry comprises:
a plurality of circuits for performing one of averaging, summation or subtraction on digital data input from the frame memory, the number of circuits matching the number of groups of columns;
a first pixel output line buffer memory for sequentially storing the processed digital data of a first row; and
a second pixel output line buffer memory for sequentially storing the processed digital data of a previous row before the data of the previous row is output over the output bus.
8. An imaging device comprising:
a pixel array organized into rows and columns, the array configured to capture an image;
column parallel analog readout circuitry connected to the columns, the column parallel analog readout circuitry converting signals associated with the captured image into digital data;
a plurality of pixel line buffer memories each being connected to and associated with a group of columns and storing a respective portion of the digital data associated with the respective group of columns;
a plurality of frame memory devices connected to the plurality of pixel line buffer memories via a plurality of data buses;
a memory controller configured to control data transfers between the frame memory devices and the plurality of pixel line buffer memories; and
an output bus configured to output digital data corresponding to the captured image.
9. The imaging device of claim 8 , further comprising digital processing circuitry connected between the pixel line buffer memories and the frame memory devices, the digital processing circuitry for processing the digital data according to an operating mode.
10. The imaging device of claim 9 , wherein multiple images are captured and stored in the frame memory devices as digital frames and wherein the digital processing circuitry processes a plurality of the stored digital frames digital data in accordance with a multiple frame mode of operation.
11. The imaging device of claim 9 , wherein multiple images are captured and stored in the frame memory devices as digital frames and wherein the digital processing circuitry processes a plurality of the stored digital frames digital data in accordance with an averaging mode of operation wherein at least two of the stored digital frames are averaged to form averaged image data before being output.
12. The imaging device of claim 9 , wherein multiple images are captured and stored in the frame memory devices as digital frames and wherein the digital processing circuitry processes a plurality of the stored digital frames digital data in accordance with a summing mode of operation wherein at least two of the stored digital frames are summed together to form summed image data before being output.
13. The imaging device of claim 9 , wherein multiple images are captured and stored in the frame memory devices as digital frames and wherein the digital processing circuitry processes a plurality of the stored digital frames digital data in accordance with a dark frame subtraction mode wherein a dark image frame from the stored digital frames is subtracted from another of the stored digital frames to form subtracted image data.
14. The imaging device of claim 9 , wherein multiple images are captured and stored in the frame memory devices as digital frames and wherein the digital processing circuitry processes a plurality of the stored digital frames digital data in accordance with a high dynamic range mode wherein a plurality of stored digital frames are combined to form a high dynamic range image, each stored digital frame corresponding to a different image exposure.
15. The imaging device of claim 8 , further comprising binning circuitry connected between the array and the pixel line buffer memories, the binning circuitry for binning pixel data to form video data during a video operating mode.
16. The imaging device of claim 15 , wherein the array is configured as a 1080 p pixel array.
17. The imaging device of claim 15 , wherein the array is configured as a 720 p pixel array.