SYSTEM AND METHODS FOR DYNAMIC RANGE EXTENSION USING VARIABLE LENGTH INTEGRATION TIME SAMPLING

• US 20070139531A1
• Filed: 12/29/2006
• Published: 06/21/2007
• Est. Priority Date: 10/15/2002
• Status: Active Grant

• Current Assignee: Applera Corporation (Thermo Fisher Scientific Incorporated)
• Original Assignee: Applera Corporation (Thermo Fisher Scientific Incorporated)
• Inventors: Sagatelyan, Dmitry, Slettnes, Tor
• Granted Patent: US 7,423,255 B2
• Time in Patent Office: Days
• US Class Current: 348/222.100
• CPC Class Codes: G01J 1/42 using electric radiation detectors optical or mechanical part G01J1/04; by comparison with a reference light or electric value G01J1/10
• CPC Class Codes: G01N 21/274 Calibration, base line adjustment, drift correction
• CPC Class Codes: G01N 21/645 Specially adapted constructive features of fluorimeters
• CPC Class Codes: G01N 2201/1241 Multirange
• CPC Class Codes: H03F 3/08 controlled by light
• CPC Class Codes: H04N 23/70 Circuitry for compensating brightness variation in the scene
• CPC Class Codes: H04N 23/73 by influencing the exposure time
• CPC Class Codes: H04N 23/741 by increasing the dynamic range of the image compared to the dynamic range of the electronic image sensors
• CPC Class Codes: H04N 23/76 by influencing the image signals
• CPC Class Codes: H04N 25/589 with different integration times, e.g. short and long exposures

Abstract

A photo-detector generated signal is measured as a sample set comprising a long signal and a short signal. The short signal is scaled to the value of the long signal if the long signal exceeds a dynamic range associated with the photo detector. In one embodiment, the short signal is obtained during a short time interval that is at the approximate middle of a long time interval such that the short and long intervals share a common median time value. Given such symmetry, an approximately linear signal yields a proportionality parameter between the long and short signals thereby allowing the short signal to be scaled. The proportionality parameter facilitates determination of an integration independent component of the photo detector signal that should be removed from the measured long and short signals before scaling. A plurality of sample sets can also be processed such that each sample set overlaps with its neighboring sample set, thereby increasing the effective number of sample sets.

Claims

1. A method for processing signals associated with a sequence analyzer, the method comprising:

obtaining first and second signals, the first and second signals obtained respectively during first and second time intervals that are temporally proximal to one another and of differing durations;

determining a scaling value and an offset value for one of the first and second signals; and

adjusting the other of the first and second signals by applying the signal offset value and the scaling value to the corresponding signal.

2. The method of claim 1, wherein said first and second signals comprise signals from a photo-detector associated with said sequence analyzer.

3. The method of claim 1, wherein said determining of the scaling value and the offset value are performed if the first or second signal exceeds a selected value.

4. The method of claim 3, wherein said selected value comprises a limit on a dynamic range associated with the first or second signal.

5. The method of claim 3, wherein the scaling value and the offset value are determined for the first or second signal that does not exceed the selected value.

6. The method of claim 1, wherein the scaling value is determined based on the first and second time intervals.

7. The method of claim 1, wherein the offset value is determined based on the first and second signals and the scaling value.

8. A method for adjusting a signal generated by a sequence analyzer, the method comprising:

determining a first signal value and a second signal value wherein the first signal value corresponds to a signal acquired during a first time interval and wherein the second signal value corresponds to a signal acquired during a second time interval, wherein the second signal value is less than the first signal value;

determining a proportionality parameter between the first and second signal values;

determining a signal offset parameter for the second signal value; and

adjusting the second signal value based on the signal offset parameter and the proportionality parameter.

9. The method of claim 8, wherein said first signal value exceeds a specified range.

10. The method of claim 8, wherein said proportionality parameter is determined based on the first and second time intervals.

11. The method of claim 8, wherein said signal offset parameter is determined based on the first and second signal values and the proportionality parameter.

12. The method of claim 8, wherein said adjusting of the second signal value comprises applying the signal offset parameter to the second signal value and scaling the resulting offset-applied second signal value by the proportionality parameter.

13. A system for processing signals associated with a sequencing apparatus, comprising:

a detector that detects a labeled sample signal and transforms said labeled sample signal into an electronic signal;

a sampling component configured to acquire one or more sample sets associated with the electronic signal, wherein each sample set comprises a first signal value and a second signal value, the first signal value corresponding to a signal acquired during a first time interval, the second signal value corresponding to a signal acquired during a second time interval that is less than the first time interval; and

a processing component configured to determine a proportionality parameter and a signal offset parameter, and determine a signal value representative of the sample set by applying the signal offset parameter and the proportionality parameter to the second signal value.

14. The system of claim 13, wherein functionalities of said sampling and processing components are provided by separate devices.

15. The system of claim 13, wherein functionalities of said sampling and processing components are provided by a single device.