THERMAL IMAGER WITH NON-UNIFORMITY CORRECTION
First Claim
Patent Images
1. A method of correcting for residual fixed pattern noise in a radiometric infrared (IR) camera, the method comprising:
- pointing the camera at a first scene external to the camera;
generating sets of IR image data, while pointing the camera at the first scene, said sets of IR image data representative of IR energy received on a focal plane array (FPA) within the camera, the FPA including a plurality of IR detector elements;
initiating a non-uniformity correction (NUC) routine, the NUC routing including;
generating a first set of IR image data representative of the IR energy received on the FPA, andgenerating NUC data from the first set of IR image data, the NUC data for correcting fixed pattern noise in the first set of IR image data;
pointing the camera at a second scene external to the camera to produce a scene that effectively is of uniform IR energy;
triggering the camera, while pointing the camera at the second scene, and initiating an NUC refinement routine including;
generating a second set of IR image data representative of IR energy received on the FPA,generating NUC refinement data from the second set of IR image data, andgenerating normalized NUC refinement data by normalizing the NUC refinement data relative to IR image data in the second set of IR image data associated with at least one of a generally centrally positioned IR detector element from the plurality of IR detector elements;
generating adjusted NUC data by adjusting the NUC data with the normalized NUC refinement data;
adjusting at least one set of the IR image data with the adjusted NUC data to minimize fixed pattern noise in the at least one set of the IR image data; and
calculating radiometric scene temperature data associated with at least a portion of the first scene based on at least a portion of at least one set of the IR image data, the NUC data, and the normalized NUC refinement data.
1 Assignment
0 Petitions
Accused Products
Abstract
Infrared cameras are susceptible to fixed-pattern noise artifacts. These artifacts are due to numerous sources and typically show up as non-uniformities in an IR image of a uniform scene. Devices for and methods of refining non-uniformity corrections in an infrared (IR) camera are provided that correct for remaining fixed pattern noise.
-
Citations
17 Claims
-
1. A method of correcting for residual fixed pattern noise in a radiometric infrared (IR) camera, the method comprising:
-
pointing the camera at a first scene external to the camera; generating sets of IR image data, while pointing the camera at the first scene, said sets of IR image data representative of IR energy received on a focal plane array (FPA) within the camera, the FPA including a plurality of IR detector elements; initiating a non-uniformity correction (NUC) routine, the NUC routing including; generating a first set of IR image data representative of the IR energy received on the FPA, and generating NUC data from the first set of IR image data, the NUC data for correcting fixed pattern noise in the first set of IR image data; pointing the camera at a second scene external to the camera to produce a scene that effectively is of uniform IR energy; triggering the camera, while pointing the camera at the second scene, and initiating an NUC refinement routine including; generating a second set of IR image data representative of IR energy received on the FPA, generating NUC refinement data from the second set of IR image data, and generating normalized NUC refinement data by normalizing the NUC refinement data relative to IR image data in the second set of IR image data associated with at least one of a generally centrally positioned IR detector element from the plurality of IR detector elements; generating adjusted NUC data by adjusting the NUC data with the normalized NUC refinement data; adjusting at least one set of the IR image data with the adjusted NUC data to minimize fixed pattern noise in the at least one set of the IR image data; and calculating radiometric scene temperature data associated with at least a portion of the first scene based on at least a portion of at least one set of the IR image data, the NUC data, and the normalized NUC refinement data. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
-
-
15. A method of tracking temperature profile changes in a scene using an infrared (IR) camera, the method comprising:
-
pointing the camera at a first scene external to the camera, the first scene being of generally non-uniform IR energy; generating sets of IR image data, while pointing the camera at the first scene, said sets of IR image data representative of IR energy received on a focal plane array (FPA) within the camera, the FPA including a plurality of IR detector elements; initiating a non-uniformity correction (NUC) routine, the NUC routing including; generating a first set of IR image data representative of the IR energy received on the FPA, and generating NUC data from the first set of IR image data, the NUC data for correcting fixed pattern noise in the first set of IR image data; triggering the camera, while pointing the camera at the first scene, and initiating an NUC refinement routine including; generating a second set of IR image data representative of IR energy received on the FPA, generating NUC refinement data from the second set of IR image data, and generating normalized NUC refinement data by normalizing the NUC refinement data relative to IR image data in the second set of IR image data associated with at least one of a generally centrally positioned IR detector element from the plurality of IR detector elements; generating adjusted NUC data by adjusting the NUC data with the normalized NUC refinement data; adjusting at least one set of the IR image data with the adjusted NUC data to minimize fixed pattern noise in the at least one set of the IR image data; displaying on a display of the IR camera an IR image of the first scene as represented by the adjusted at least one set of the IR image data, whereby such displayed IR image is generally uniform. - View Dependent Claims (16)
-
-
17. A radiometric infrared (IR) camera for correcting for residual fixed pattern noise, comprising:
-
a housing; a focal plane array (FPA) mounted within the housing and adapted to receive IR energy, the FPA comprising a plurality of IR detector elements and generating sets of IR image data representing IR energy received on the FPA; a lens mounted on the housing for directing IR energy from a target scene onto the FPA; a shutter disposed within the housing, the shutter movable between open and closed positions, the closed position being such that the shutter is positioned between the lens and the FPA to prevent IR energy from the target scene from reaching the FPA, the open position permitting IR energy from the scene to reach the FPA; a switch supported by the housing, the switch, when triggered, initiating a non-uniformity correction (NUC) refinement routine during which the shutter remains in the open position and a first set of IR image data is generated representing IR energy levels received on the FPA; a processor operatively coupled to the FPA for receiving and processing the sets of IR image data, the processor for initiating a NUC routine during which the shutter is temporarily moved to the closed position and a second set of IR image data is generating representing IR energy received on the FPA, the processor generating offset data from the second set of IR image data, the processor generating NUC refinement data from the first set of IR image data, the processor generating adjusted NUC data by adjusting the NUC data with the NUC refinement data, the adjusted NUC data for use by the camera to provide fixed-pattern noise correction; and a display supported by the housing and operatively connected to the processor for displaying an adjusted IR image of the target scene based on the adjusted NUC data.
-
Specification