Dual exposure for image sensor

• US 20060192873A1
• Filed: 01/31/2006
• Published: 08/31/2006
• Est. Priority Date: 02/01/2005
• Status: Active Grant

• Current Assignee: Transchip Israel Limited (Samsung Electronics Co. Ltd.)
• Original Assignee: TransChip, Inc. (Samsung Electronics Co. Ltd.)
• Inventors: Yaffe, Yoel
• Granted Patent: US 7,554,588 B2
• Time in Patent Office: Days
• US Class Current: 348/297
• CPC Class Codes: H04N 25/53 Control of the integration time
• CPC Class Codes: H04N 25/531 by controlling rolling shutters in CMOS SSIS
• CPC Class Codes: H04N 25/533 by using differing integration times for different sensor regions
• CPC Class Codes: H04N 25/535 by dynamic region selection
• CPC Class Codes: H04N 25/583 with different integration times
• CPC Class Codes: H04N 25/778 comprising amplifiers shared between a plurality of pixels, i.e. at least one part of the amplifier must be on the sensor array itself

Abstract

A method of capturing an image of a scene using an image capture device having an array of pixels arranged into a plurality of rows includes, for a first duration, capturing a first portion of the scene with a first plurality of the rows and, for a second duration that is longer than the first duration, capturing a second portion of the scene with a second plurality of the rows. If a pixel value is below a first threshold, an interpolated pixel value is used. If the pixel value is above a second predetermined threshold, a different interpolated pixel value is used.

Claims

1. A method of capturing an image of a scene using an image capture device having an array of pixels arranged into a plurality of rows, the method comprising:

for a first duration, capturing a first portion of the scene with a first plurality of the rows;

for a second duration that is longer than the first duration, capturing a second portion of the scene with a second plurality of the rows;

for each pixel in the first plurality of the rows;

determining whether a pixel value associated with the pixel is below a first predetermined threshold;

based on the determination;

if the pixel value is above the first predetermined threshold;

creating a scaled-up pixel value by increasing the pixel value by a scale factor;

using the scaled-up pixel for a final pixel value; and

if the pixel value is below the first predetermined threshold, using an interpolated pixel value for the final pixel value; and

storing the final pixel value as part of the captured image;

for each pixel in the second plurality of the rows;

determining whether a pixel value associated with the pixel is above a second predetermined threshold;

based on the determination;

if the pixel value is below the second predetermined threshold, using the pixel value for a final pixel value; and

if the pixel value is above the second predetermined threshold, using an interpolated pixel value for the final pixel value; and

storing the final pixel value as part of the captured image; and

displaying at least a portion of the captured image.

2. The method of claim 1, wherein the first predetermined threshold comprises a dynamic threshold.

3. The method of claim 1, wherein the second predetermined threshold comprises a saturation threshold.

4. The method of claim 1, wherein the first plurality of the rows comprises every other row.

5. The method of claim 1, wherein the first plurality of the rows comprises every other row pair.

6. The method of claim 1, wherein the image capture device comprises a CMOS image capture device.

7. The method of claim 1, wherein the interpolated pixel value comprises a pixel value determined by averaging at least two other pixel values.

8. The method of claim 1, wherein the scale factor is a ratio of the first and second durations.

9. An image capture device, comprising:

an array of pixels arranged into a plurality of rows;

an interpolator;

a storage arrangement; and

circuitry configured to control the operation of the pixels to thereby capture an image of a scene by;

for a first duration, capture a first portion of the scene with a first plurality of the rows;

for a second duration that is longer than the first duration, capture a second portion of the scene with a second plurality of the rows; and

output pixel values to the interpolator;

wherein the interpolator is programmed to;

for each pixel in the first plurality of the rows;

determine whether a pixel value associated with the pixel is below a first predetermined threshold;

based on the determination;

if the pixel value is above the first predetermined threshold;

 

create a scaled-up pixel value by increasing the pixel value by a scale factor; and

 

use the scaled-up pixel value for a final pixel value; and

if the pixel value is below the first predetermined threshold, use an interpolated pixel value for the final pixel value;

for each pixel in the second plurality of the rows;

determine whether a pixel value associated with the pixel is above a second predetermined threshold;

based on the determination;

if the pixel value is below the second predetermined threshold, use the pixel value for a final pixel value; and

if the pixel value is above the second predetermined threshold, use an interpolated pixel value for the final pixel value; and

wherein the storage arrangement is configured to receive the final pixel values from the interpolator and store the final pixel values as the captured image.

10. The image capture device of claim 9, wherein the first predetermined threshold comprises a dynamic threshold.

11. The image capture device of claim 9, wherein the second predetermined threshold comprises a saturation threshold.

12. The image capture device of claim 9, wherein the first plurality of the rows comprises every other row.

13. The image capture device of claim 9, wherein the first plurality of the rows comprises every other row pair.

14. The image capture device of claim 9, wherein the image capture device comprises a CMOS image capture device.

15. The image capture device of claim 9, wherein the interpolated pixel value comprises a pixel value determined by averaging at least two other pixel values.

16. The image capture device of claim 9, wherein the interpolated pixel value comprises a pixel value determined by averaging at least two other pixel values.

17. The image capture device of claim 16, wherein the interpolator is further programmed to calculate the interpolated pixel value.

18. The image capture device of claim 9, wherein the scale factor is a ratio of the first and second durations.

19. The image capture device of claim 18, wherein the interpolator is further programmed to calculate the scale factor.