some edge-preserving blur operations can also sharpen edges. As an example, you could try the 'Thresholded Blur' filter:
> Dear colleagues,
>
> A simple need, but I could not find the right solution in ImageJ. I am
> sorry if it is obvious.
>
> Is there a filter to increase edge sharpness and reduce the effect known as
> "halo effect" in optical microscopy?
>
> At the edges of bright objects and a dark background (or vice-versa) there
> are normally pixels with intermediate pixel values. If other objects in the
> image have these pixel values, when they are segmented the edges of bright
> objects will also appear.
>
> Even though these fake edges can be corrected by a morphological open, it
> is normally better to pre-process the image with an edge enhancement filter
> (some times called delineate) to increase the edge sharpness and reduce the
> amount of intermediate pixels.
>
> Any hints?
>
> Thank you!
>
> Prof. Sidnei Paciornik
> Grupo de Análise de Imagens e Microscopia Digital
> DEMa <
http://www.dema.puc-rio.br/> - Departamento de Engenharia de Materiais
> PUC-Rio <
http://www.puc-rio.br/>
> Rua Marquês de São Vicente 225
> Prédio Leme, Sala 501L
> Gávea - Rio de Janeiro - RJ
> 22451-900 - Brasil
> tel: (55)(21)3527-1243
>
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