IMAGE SENSOR WITH EXPANDING DYNAMIC RANGE

• US 20090127434A1
• Filed: 12/23/2004
• Published: 05/21/2009
• Est. Priority Date: 10/29/2004
• Status: Active Grant

• Current Assignee: Mtekvision Co.Ltd.
• Original Assignee: Mtekvision Co.Ltd.
• Inventors: Kim, Yong-hwan
• Granted Patent: US 7,667,172 B2
• Time in Patent Office: Days
• US Class Current: 250/208.100
• CPC Class Codes: H04N 23/667 Camera operation mode switching, e.g. between still and video, sport and normal or high- and low-resolution modes
• CPC Class Codes: H04N 25/583 with different integration times
• CPC Class Codes: H04N 25/616 involving a correlated sampling function, e.g. correlated double sampling [CDS] or triple sampling
• CPC Class Codes: H04N 25/75 Circuitry for providing, modifying or processing image signals from the pixel array
• CPC Class Codes: H04N 25/767 Horizontal readout lines, multiplexers or registers

Abstract

A conventional image sensor has a narrow dynamic range, so that the conventional image sensor has the limitation of not representing very dark portions or very bright portions depending on the exposure time when representing an image having such dark and bright portions. The present invention provides an image sensor including at least two storage units for respectively storing at least two image signals; a first switch unit for performing switching applied image signals to be respectively stored in the at least two storage units; and a second switch unit respectively connected to the at least two storage units and for equalizing the image signals stored in the at least two storage units.

Claims

1. An image sensor, comprising:

a photodetector for generating analog image signals;

at least two storage units for storing at least two image signals respectively; and

a plurality of switch units including;

a first switch unit constructed to connect the photodetector to the at least two storage units for permitting transfer of the at least two image signals collected in the photodetector, the first switch unit being constructed to switch applied image signals to be stored in one of the at least two storage units; and

a second switch unit constructed to connect the at least two storage units each other for equalizing the image signals stored in the at least two storage units.

2. The image sensor as set forth in claim 1, wherein the storage units are capacitors.

3. The image sensor as set forth in claim 1, wherein the first switch unit includes at least two switches respectively connected to the at least two storage units.

4. The image sensor as set forth in claim 3, wherein the switches are transistors.

5. The image sensor as set forth in claim 1, wherein the second switch unit is a transistor.

6. The image sensor as set forth in claim 1, wherein the image signals stored in the at least two storage units are represented by voltage.

7. The image sensor as set forth in claim 1, wherein the second switch unit is connected in series to each of the at least two storage units.

8. The image sensor as set forth in claim 1, wherein the image signals are equalized by switching the image signals to an average value.

9. The image sensor as set forth in claim 1, wherein the equalized image signals are respectively stored in the at least two storage units.

10. An image sensor, comprising:

a first input line for transmitting an image signal;

a second input line for transmitting a reset signal;

a third input line for transmitting an average reset signal;

a comparator connected to the first input line, second input line and third input line; and

a switch unit constructed to switch one of the reset signal and the average reset signal, which are input through the second input line and third input line, to be input to the comparator.

14. The image sensor as set forth in claim 10, wherein the switch unit includes at least one transistor.

11-13. -13. (canceled)

15. An image sensor, comprising:

a photodetector for generating analog image signals;

at least two storage units for respectively storing at least two image signals;

a plurality of switch units including;

a first switch unit constructed to connect the photodetector to the at least two storage units for permitting transfer of the at least two image signals collected in the photodetector, the first switch unit being constructed to switch applied image signals to be stored in one of the at least two storage units; and

a second switch unit constructed to connect the at least two storage units each other for equalizing the image signals stored in the at least two storage units;

a first input line to which an equalized image signal is input;

a second input line to which a predetermined average reset signal is input; and

a comparator connected to the first input line and second input line, the comparator being configured to compare the equalized image signal with the predetermined average reset signal.

16. A signal processing method in an image sensor, comprising the steps of:

receiving at least two image signals;

equalizing the at least two image signals;

comparing the equalized image signal with a predetermined average reset signal; and

outputting a digitized image signal based on a result of the comparison.

17. The signal processing method as set forth in claim 16, wherein the step of outputting a digitized image comprises the step of:

generating a digitized image signal based on a result of the comparison.

18. (canceled)

19. An image sensor, comprising:

a photodetector for generating analog image signals;

at least two storage means for storing at least two image signals respectively; and

a plurality of means for switching including;

a first switching means constructed to connect the photodetector to the at least two storage means for permitting transfer of the at least two image signals collected in the photodetector, the first switch means being constructed to switch applied image signals to be stored in one of the at least two storage means; and

a second switching means constructed to connect the at least two storage means each other for equalizing the image signals stored in the at least two storage means.

20. The image sensor as set forth in claim 19, wherein the storage means are capacitors.

21. The image sensor as set forth in claim 19, wherein the first switching means includes at least two switches respectively connected to the at least two storage means.

22. The image sensor as set forth in claim 19, wherein the switching means are transistors.

23. The image sensor as set forth in claim 19, wherein the image signals are equalized by switching the image signals to an average value.

24. The image sensor as set forth in claim 19, wherein the equalized image signals are respectively stored in the at least two storage means.