ee.Image.spectralGradient
Computes the spectral gradient over all bands of an image (or the first band if the image is Array typed) by computing the per-pixel difference between the spectral erosion and dilation with a given structuring kernel and distance metric. See: Plaza, Antonio, et al. 'Spatial/spectral endmember extraction by multidimensional morphological operations.' IEEE transactions on geoscience and remote sensing 40.9 (2002): 2025-2041.
| Usage | Returns |
|---|
Image.spectralGradient(metric, kernel, useCentroid) | Image |
| Argument | Type | Details |
|---|
this: image | Image | The input image. |
metric | String, default: "sam" | The spectral distance metric to use. One of 'sam' (spectral angle mapper), 'sid' (spectral information divergence), 'sed' (squared Euclidean distance), or 'emd' (earth movers distance). |
kernel | Kernel, default: null | Connectedness kernel. Defaults to a square of radius 1 (8-way connected). |
useCentroid | Boolean, default: false | If true, distances are computed from the mean of all pixels under the kernel instead of the kernel's center pixel. |
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Last updated 2024-07-13 UTC.
[null,null,["Last updated 2024-07-13 UTC."],[[["Computes the spectral gradient of an image by calculating the difference between spectral erosion and dilation using a specified kernel and distance metric."],["Offers a choice of four spectral distance metrics: SAM, SID, SED, and EMD."],["Allows customization of the connectedness kernel and the method of distance calculation (from the kernel's center or centroid)."],["Primarily used for spatial/spectral endmember extraction in hyperspectral images, as described in the cited research by Plaza et al."],["Operates on all bands of multi-band images or the first band of Array-typed images."]]],[]]