MISR: In-Flight Radiometric Calibration and Characterization Plan

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6.2.1 PSF deconvolutionDuring preflight testing it was determined that the contrast target specification, given inthe [ISR], is violated for a 24x24 pixel lake-type scene surrounded by a "land" background.Scattering within the focal plane, primarily between the filter and detector, has been attributed asthe cause. The MISR science team has elected to correct for this haloing affect in groundprocessing.The algorithm selected is based upon the maximum-likelihood approach. It makes anestimate of the scene, then using the point-spread-function (PSF) for that array, predicts the DNdistribution across the array, for that assumed scene. Then, using the ratio of the true measuredscene to that of the image predicted from the estimated scene, the estimated scene is updated. Ithas been shown that this algorithm is computationally efficient, and that the scene is restoredwithin a few iterations. Only a small number of iterations are required because the halo intensitiesare small, and thus the observed signal is a good first-order approximation to the restored image.The PSF functions for the line array are obtained by averaging ten PSF measurementsacross a pixel. Each individual measurement is the result of sub-pixel illumination at variousspacious locations across the array. The averaged PSF profile is nearly spatially invariant acrossthe array. A representative, field-independent profile will be used for each array.6.2.2 Spectral in-band scalingThe differences in spectral in-band response across an array, and from one camera toanother, has been measured in the preflight test program. The largest variation occurs for thosefew cameras where the filter was cut in the radial direction relative to the deposition center duringfilter fabrication. (Filter uniformity is more uniform along lines of equal radius). Differences innominal band shape, as compared to the measured per pixel in-band response, can be accountedfor by a scale factor applied to the retrieved radiances. This scale factor is the ratio of the solarexo-atmospheric irradiance, averaged over the desired nominal band profile, to the solar exoatmosphericirradiance averaged by the actual (measured) in-band response profile. The nominalprofile will have no response at out-of-band wavelengths. It has yet to be determined if thenominal profile will be constructed as an average, or representative profile from the measureddata.Ideally the out-of-band subtraction would be done prior to the in-band scaling. Theprocesses have been ordered otherwise, to allow the spectral bands to be registered, retrievingscene spectral response information prior to the out-of-band subtraction. Provided the in-bandscaling factor is near unity, there is little difference between the desired correction order and thatto be implemented. The out-of-band correction is planned as a Level 2 processing step. Thus, thiscorrection can be implemented or not, depending on product need.6.3 ARP GENERATIONThe Ancillary Radiometric Product (ARP) is the primary deliverable from the in-flightradiometric calibration task. It will be maintained throughout the mission, to give an updatedaccount of the instrument radiometric response, as well as other instrument descriptors. Staticparameters will be determined from the preflight data alone; other parameters will be updated in-6. Level 1B1 radiometric product algorithms52
flight. Generation of the updated parameters will be facilitated by standardized SCF processingalgorithms and procedures. Radiance scaling and conditioning will proceed using the updatedparameters. Should MISR radiances be reprocessed at some time, the DAAC algorithms willmake use of the parameters which best represent the instrument response at the time of dataacquisition.In-flight Radiometric Calibration and Characterization Plan, JPL D-1331553
Page 6: 10.4.2 Radiative transfer. . . . .
Page 9 and 10: 1. INTRODUCTION1.1 PURPOSEThis docu
Page 11 and 12: • MISR Algorithm Development Plan
Page 13 and 14: 2.1 MISR SCIENCE OBJECTIVES2. EXPER
Page 15 and 16: In addition to these modes, the ins
Page 17 and 18: Table 2.1. Level 1A productProductL
Page 19 and 20: Table 2.4. Level 1B1 Ancillary Radi
Page 21 and 22: 3. CALIBRATION OVERVIEW3.1 REQUIREM
Page 23 and 24: equally to filter pinholes or scatt
Page 25 and 26: PREFLIGHTDATAIFRCCactivityOtheracti
Page 27 and 28: Multiple methodologies are utilized
Page 29 and 30: laboratory environment. This includ
Page 31 and 32: 4. PREFLIGHT CALIBRATION AND CHARAC
Page 33 and 34: determination was originally planne
Page 35 and 36: Cause: The filters are non uniform
Page 37 and 38: is the affected area is about 30 pi
Page 39 and 40: 5. IN-FLIGHT RADIOMETRIC CALIBRATIO
Page 41 and 42: esponse functions will be verified
Page 43 and 44: the array. Dark current is expected
Page 45 and 46: OBC design effort. The actual uncer
Page 47 and 48: 5.2.1 High-altitude sensor-based ca
Page 49 and 50: laboratory measurements. In order t
Page 51: 6. LEVEL 1B1 RADIOMETRIC PRODUCT AL
Page 55 and 56: 7. CHARACTERIZATIONThe radiance unc
Page 57 and 58: 7.1.4 PolarizationMISR has been des
Page 59 and 60: It is believed that the evaluation
Page 61 and 62: 8. CALIBRATION INTEGRITYCalibration
Page 63 and 64: The baseline CAM is the most useful
Page 65 and 66: had all lamps on, and the satellite
Page 67 and 68: 9. MANAGEMENT9.1 PERSONNEL ROLES9.1
Page 69 and 70: EurOpto (preflight radiometriccal.)
Page 71 and 72: PRINCIPALINVESTIGATORDavid J. Diner
Page 73 and 74: • Identifying/specifying all of t
Page 75 and 76: 10. REFERENCES10.1 MISR EXPERIMENT(
Page 77 and 78: 10.3 IN-FLIGHT CALIBRATION METHODOL
Page 79 and 80: 38. Vane, G., T.G. Chrien, J.H. Rei
Page 81 and 82: APPENDIX A. NOMENCLATUREThe followi
Page 83 and 84: A.4 CHARACTERIZATIONcalibration. Th
Page 85 and 86: G 0 , G 1 , and G 2 are the respons
Page 87 and 88: APPENDIX B. CALIBRATION MODE SEQUEN
Page 89 and 90: In Cal-Dark data are acquired over
Page 91 and 92: Config. Home Run is a commanding of
Page 93 and 94: Repeat for 200 line repeat times, t

MISR: In-Flight Radiometric Calibration and Characterization Plan

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