Correction of corrupted elements in sensors using analog/multi-level non-volatile memory

• US 6,760,068 B2
• Filed: 12/31/1998
• Issued: 07/06/2004
• Est. Priority Date: 12/31/1998
• Status: Expired due to Term

• Current Assignee: SanDisk Technologies LLC (Western Digital Corporation)
• Original Assignee: SanDisk Corporation (Western Digital Corporation)
• Inventors: Petropoulos, Leo, Wong, Sau C.
• Primary Examiner(s): Garber, Wendy R.
• Assistant Examiner(s): WHIPKEY, JASON T
• Application Number:
  US09/224,168
• Publication Number:
  US 20030090580A1
• Time in Patent Office: 2,014 Days
• Field of Search: 348/247, 348/246, 348/251, 348/254, 348/255
• US Class Current: 348/247
• CPC Class Codes: H04N 25/68 applied to defects

Abstract

A method and system using a sensor array includes a programmable analog/multi-level memory array for modifying individual outputs from elements in the sensor array in order to obtain a desired sensor array output. The memory array can be programmed with data corresponding to desired modifications, such as low and high offset voltage correction, low gain correction, and gamma correction. Consequently, by utilizing arithmetic circuits, the adverse effects of corrupted elements in a sensor can be corrected by re-programming the memory array with different modification data as the need arises.

Claims

1. A method of processing sensor element outputs in a sensor array, comprising:

storing voltages corresponding to a desired modification in a programmable analog/multi-level memory array; and

modifying the sensor element outputs with associated ones of the voltages stored in the memory array, wherein said sensor element outputs are multiplied with gamma correction values, wherein the memory array and the sensor array are the same size.

2. The method of claim 1, further comprising bypassing the modifying for sensor element outputs not needing modification.

3. A method of processing sensor element outputs in a sensor array, comprising:

storing voltages corresponding to a desired modification in a programmable analog/multi-level memory array, wherein each of said voltages is associated with a single one of said sensor elements; and

modifying the sensor element outputs with associated ones of the voltages stored in the memory array, wherein the memory array is smaller than the sensor array.

4. The method of claim 3, further comprising transferring corresponding pairs of sensor element outputs and the voltages stored in the memory array to a modification circuit after said storing.

5. The method of claim 3, further comprising processing said modified sensor element outputs after said modifying.

6. The method of claim 3, wherein said sensor array is an image sensor array.

7. The method of claim 3, wherein said modifying comprises adding one of the voltages stored in the memory array to a corresponding sensor element output, subtracting one of the voltages stored in the memory array from a corresponding sensor element output, or multiplying one of the voltages stored in the memory array with a corresponding sensor element output.

8. A method of modifying elements in a sensor array, comprising:

programming modification voltages in memory cells of an analog/multi-level memory array, wherein the memory array is smaller than the sensor array and wherein each of said modification voltages corresponds with a single one of said sensor elements;

reading the modification voltage in the memory cell corresponding to a first voltage from an element in the sensor array requiring modification;

supplying the modification voltage and the first voltage to a modification circuit; and

modifying the first voltage with the modification voltage, wherein the modification voltages are determined by;

exposing sensor elements in a sensor with a known signal;

measuring the voltages from the sensor elements;

comparing the measured voltages with voltages desired from exposing the sensor elements with the known signal; and

performing an arithmetic operation to obtain a modification voltage, wherein the modification voltage modifies a corresponding measured voltage to obtain a desired sensor element voltage.

9. A signal processing system comprising:

a sensor, wherein the sensor outputs voltages forming an array of elements;

an analog/multi-level memory array having memory cells corresponding to the array of elements;

a modification circuit coupled to the sensor and the memory array, wherein the modification circuit modifies voltages of the array of elements with corresponding voltages of the memory cells, wherein the memory array is smaller than the array of elements; and

a decoder circuit coupled to the memory array and the array of elements for determining the memory cell in the memory array corresponding to the voltage from the array of elements requiring modification.

10. The system of claim 9, wherein the sensor is an image sensor.

11. The system of claim 9, further comprising a signal processing circuit coupled to the modification circuit for processing modified voltages.

12. The system of claim 9, wherein the modification circuit comprises a summing circuit.

13. The system of claim 12, wherein the modification circuit further comprises a subtractor circuit.

14. The system of claim 13, wherein the modification circuit further comprises a multiplier circuit.

15. A signal processing, comprising:

a sensor, wherein the sensor outputs voltages forming an array of elements;

an analog/multi-level memory array having memory cells corresponding to the array of elements; and

a modification circuit coupled to the sensor and the memory array, wherein the modification circuit modifies voltages of the array of elements with corresponding voltages of the memory cells, wherein the modification circuit performs gamma correction, wherein the memory array and the array of elements are the same size.

16. A sensor correction system, comprising:

a sensor array having a first plurality of memory cells for storing sensor voltages corresponding to the outputs of the sensor array;

a programmable analog/multi-level memory array having a second plurality of memory cells each comprising a source, a drain and a control gate for storing modification voltages corresponding to desired modifications of the sensor voltages, wherein the second plurality of memory cells is smaller than the first plurality of memory cells, wherein each of said modification voltages corresponds with a single one of said sensor elements, and wherein the second plurality of memory cells is arranged in rows and columns in the array;

a column decoder having bit-lines coupling the drains of memory cells in each column of the array;

a row decoder having word-lines coupling the control gates of memory cells in each row of the array and source-lines coupling the sources of memory cells in each row of the array;

a routing circuit coupled to the sensor array and to the programmable analog/multi-level memory array for selecting a first voltage from the sensor array for modification and a corresponding second voltage from the analog/multi-level memory array; and

a modification circuit for modifying the first voltage with the second voltage, wherein the first plurality of memory cells is larger in number than the second plurality of memory cells.

17. The system of claim 16, further comprising an analog signal processing circuit coupled to the modification circuit and a visual display device coupled to the analog signal processing circuit.

18. The system of claim 17, further comprising a digital signal processing circuit coupled to the analog signal processing circuit.

19. The system of claim 18, wherein the digital signal processing circuit performs encoding and compression of the signal from the analog signal processing circuit.