Highlight Edges in an Image with a Custom-Designed Differentiator FIR Filter

Start with an image:

In[1]:=

img=

;

Take a row of pixel values of the image:

In[2]:=

row=ImageData[img]〚200〛;

Use

to build a custom-designed differentiator (FIR) digital differentiator filter:

In[3]:=

h=EquirippleFilterKernel[{"Differentiator",{{0,0.9π}},{1}},21];

Apply the filter to the row of pixel values, using

:

In[4]:=

GraphicsRowListLinePlotrow,

,ListLinePlotListConvolve[h,row,11],



Out[4]=

Use

to apply the filter to the full 2D image as well:

In[5]:=

GraphicsGridListLinePlotrow,

,ListLinePlotListConvolve[h,row,11],

,{img,ImageConvolve[img,{h}]//ImageAdjust},

...



Out[5]=

Try using

to highlight the edges:

In[6]:=

GraphicsRow{img,DifferentiatorFilter[img,0.5π,5]//ImageAdjust},

...



Out[6]=

Wolfram Language Example Repository