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flatField

Apply flat field correction to hyperspectral data cube

    Description

    example

    correctedData = flatField(inputData,roi) applies flat field correction to the hyperspectral data, inputData, using the flat field mean spectrum calculated in the specified region of interest (ROI) of the hyperspectral data. A valid ROI has these characteristics:

    • Topographically flat

    • Spectrally flat (uniform spectral response)

    • Strong signal source to reduce the impact of random noise

    Note

    This function requires the Image Processing Toolbox™ Hyperspectral Imaging Library. You can install the Image Processing Toolbox Hyperspectral Imaging Library from Add-On Explorer. For more information about installing add-ons, see Get and Manage Add-Ons.

    Examples

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    Read hyperspectral data into the workspace.

    hcube = hypercube('paviaU');

    Specify the ROI from which to calculate the flat field mean spectrum.

    roi = [1 1 10 10];

    Apply the flat field correction to the hyperspectral data.

    hcube_flatfield = flatField(hcube,roi); 

    Input Arguments

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    Input hyperspectral data, specified as one of these options:

    • hypercube object — The DataCube property of the hypercube object stores the hyperspectral data cube.

    • M-by-N-by-C numeric array — M and N are the number of rows and columns of pixels in the hyperspectral data, respectively. C is the number of spectral bands in the hyperspectral data.

    The input pixel values can be digital numbers, TOA radiance values, or TOA reflectance values. To convert a hypercube containing digital numbers to a hypercube containing TOA radiance or TOA reflectance data, use the dn2radiance or dn2reflectance function, respectively.

    ROI for the calculation of the flat field mean spectrum, specified as a 4-element vector of positive integers of the form [xmin ymin width height]. The vector defines a rectangular ROI within the hyperspectral data. xmin and ymin are the xy-coordinates of the upper-left corner of the ROI. width and height are the width and height, respectively, of the ROI, in pixels

    Output Arguments

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    Corrected hyperspectral data, returned as a hypercube object or M-by-N-by-C numeric array consistent with the input data, inputData. If the input data in inputData is of data type double, then the corrected data is also of data type double. Otherwise, the corrected data is of data type single.

    References

    [1] Roberts, D. A., Y. Yamaguchi, and R. J. P. Lyon. "Comparison of Various Techniques for Calibration of AIS Data." In Proceedings of the Second Airborne Imaging Spectrometer Data Analysis Workshop, ed. Gregg Vane and Alexander F. H. Goetz, 21 -30. Pasadena: Jet Propulsion Laboratory, 1986.

    Introduced in R2020b