median and mean filtering.

asked 2015-02-09 01:51:16 -0500

KansaiRobot gravatar image

Hello and thanks for your help

Looking through the documentation I found the function medianblur

it seems to apply the median of a sector of an image defined by a square of some size.

My first question is: Is there something similar but for mean not median??

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my second question is , what if afterwards I want to apply some operation to my original image and to the mean image. (substracting, multiplying by some scalar, adding) . Can I do this just with +.* /. as if images were just simple matrices... (which they are, no???)

Thanks a thousand

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Comments

1

IMHO blur is what you need... And the operation on arrays are here

thdrksdfthmn gravatar imagethdrksdfthmn ( 2015-02-09 03:06:08 -0500 )edit

Thank you. I will try those .

KansaiRobot gravatar imageKansaiRobot ( 2015-02-12 23:54:08 -0500 )edit

@KansaiRobot Mean filtering is defined in terms of convolution followed by normalization. Convolution satisfies operator commutative property, therefore it can commute with some of those mathematical operations you mentioned. However, to construct some useful algorithms, you have to have college-level mathematical understanding in the field called "signal processing". Otherwise it will be too hard or impossible to understand or explain.

rwong gravatar imagerwong ( 2015-04-03 19:34:52 -0500 )edit

Another property satisfied by the rectangular mean filter is that it is separable - it can be represented as a single-column mean filtering followed by single-row mean filtering, or vice versa. These operators are also commutative. Therefore, it is true that you can do a lot of things in many different ways - but to understand that, you need some good knowledge of convolution.

rwong gravatar imagerwong ( 2015-04-03 19:37:47 -0500 )edit