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US 10,295,230 B2Granted
Thermoelectric cooling management
AssigneeSensors Unlimited, Inc.
InventorsJonathan Nazemi, Michael Delamere, Marc Hansen, Jinguo Yu
Life of this patent
Estimating the term…
Abstract
A method of controlling FPA system stabilization includes calculating FPA adjustments as a function of FPA temperature and adjusting a TEC set point to assist the FPA adjustments in attaining a predetermined level of FPA performance. Adjusting the TEC set point can include adjusting the TEC set point as a function of at least one of ambient temperature, FPA temperature, or disparity between the predetermined level of FPA performance and a level of FPA performance obtainable by calculating the FPA adjustments as a function of FPA temperature alone without adjusting the TEC set point.
Claims16
A method of controlling FPA system stabilization comprising:
- calculating FPA adjustments as a function of FPA temperature;
- and
- adjusting a TEC set point to assist the FPA adjustments in attaining a predetermined level of FPA performance, wherein calculating FPA adjustments includes:
- determining an FPA temperature;
- calculating an FPA system gain as a function of the FPA temperature;
- applying the FPA system gain at the FPA temperature to condition output of the FPA to produce temperature independent image data at the TEC set point;
- calculating a non-uniformity correction map on a pixel by pixel basis for the FPA, wherein non-uniformity correction for each pixel is a function of the FPA temperature;
- and
- applying the non-uniformity correction map to the imaging data from the FPA to produce temperature dependent non-uniformity corrected image data at the TEC set point, wherein calculating the non-uniformity correction map includes a process that does not itself perform a system gain correction in calculating the non-uniformity correction map.
6 more elements
A method of controlling FPA system stabilization comprising:
- calculating FPA adjustments as a function of FPA temperature;
- and
- adjusting a TEC set point to assist the FPA adjustments in attaining a predetermined level of FPA performance, wherein calculating FPA adjustments includes:
- determining an FPA temperature;
- calculating an FPA system gain as a function of the FPA temperature;
- applying the FPA system gain at the FPA temperature to condition output of the FPA to produce temperature independent image data at the TEC set point;
- calculating a non-uniformity correction map on a pixel by pixel basis for the FPA, wherein non-uniformity correction for each pixel is a function of the FPA temperature;
- and
- applying the non-uniformity correction map to the imaging data from the FPA to produce temperature dependent non-uniformity corrected image data at the TEC set point, wherein calculating the FPA system gain is governed by
- Vgain(T) =[(p1 +p3*Tref)*Vgainref +p2*(Tref−T)]/(p1 +p3*T)
- wherein Vgain is a variable control level which correlates to the FPA system gain, Vgainref is the value of the control level which sets the FPA system gain at the reference temperature (Tref), and p1, p2, and p3 are empirically derived coefficients.
8 more elements
A method of controlling FPA system stabilization comprising:
- calculating FPA adjustments as a function of FPA temperature;
- and
- adjusting a TEC set point to assist the FPA adjustments in attaining a predetermined level of FPA performance, wherein calculating FPA adjustments includes:
- determining an FPA temperature;
- calculating an FPA system gain as a function of the FPA temperature;
- applying the FPA system gain at the FPA temperature to condition output of the FPA to produce temperature independent image data at the TEC set point;
- calculating a non-uniformity correction map on a pixel by pixel basis for the FPA, wherein non-uniformity correction for each pixel is a function of the FPA temperature;
- and
- applying the non-uniformity correction map to the imaging data from the FPA to produce temperature dependent non-uniformity corrected image data at the TEC set point, wherein calculating a non-uniformity correction map on a pixel by pixel basis is governed by
- δ
-
-
- Ic
- =
- [
- p
-
-
- 0
- +
- p
-
-
- 1
- ×
- log
-
-
- 10
-
- (
- T
- )
- ]
- ×
- (
- Iraw
- -
- ∑
- n
- =
- 0
- ,
- 1
- ,
- 3
- ,
- 5
-
-
- (
- a
- n
- ×
- (
- T
- -
- T
- min
- T
- max
- -
- T
- min
- )
- n
- )
- )
- wherein δIc represents the change for a respective pixel from its dark level to a desired correction value, Iraw is the raw value of the pixel in digital numbers, Tmax and Tmin are maximum and minimum temperatures, respectively, for normalizing FPA temperature T, and p0, p1, and a0, a1, a3, and a5 are empirically derived coefficients.
66 more elements
An imaging system comprising:
- a focal plane array (FPA);
- a thermoelectric cooler (TEC) operatively connected to cool the FPA;
- a temperature sensor operatively connected to measure temperature of the FPA;
- and
- a module operatively connected to the FPA, TEC, and temperature sensor to:
- calculate FPA adjustments as a function of FPA temperature by:
- calculating FPA system gain for the FPA as a function of the FPA temperature, system gain for the FPA at a reference temperature, and empirically derived coefficients, and to apply the FPA system gain to condition output of the FPA to produce temperature independent image data;
- or
- applying a non-uniformity correction map on a pixel by pixel basis for the FPA as a function of the FPA temperature and empirically derived coefficients, and to apply the non-uniformity correction map to condition output of the FPA to produce temperature dependent non-uniformity corrected image data, wherein the non-uniformity correction map calculated with a process that does not itself perform a system gain correction in calculating the non-uniformity correction map;
- and
- adjust set point of the TEC to assist the FPA adjustments in attaining a predetermined level of FPA performance.
8 more elements
Dependencies are inferred from the claim text.