| The Sobel operator |
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| Better
approximations of the derivatives exist |
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| • | The Sobel
operators below are very commonly used |
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| • | The standard
defn. of the Sobel operator omits the 1/8 term |
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| – | doesn’t make a
difference for edge detection |
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| – | the 1/8 term is
needed to get the right gradient value, however |
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