Efficient Zooming Using Multiscale Pyramids

Start with a 34-megapixel image:

In[1]:=

img=ExampleData[{"TestImage","Volubilis"}];

Check the image dimensions:

In[2]:=

ImageDimensions[img]

Out[2]=

{9010,3791}

Generate a lowpass image pyramid of the image:

In[3]:=

pyr=ImagePyramid[img,{"Lowpass","Linear"},{80}]

Out[3]=

ImagePyramid



Type: Gaussian Levels: 7
Dimensions: {9010,3791} ↔ {141,59}

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

Obtaining the resized image from the image pyramid is about 100 times faster compared to directly resizing the image:

In[4]:=

RepeatedTiming[ImageResize[#,{512}];]&/@{InverseImagePyramid[pyr,{512}],img}

Out[4]=

{{0.00606388,Null},{0.474203,Null}}

See the smooth zooming of a large image:

In[5]:=

Manipulate[With[{scale=

-s

2

,dims=First[pyr["ImageDimensions"]]},ImageResize[ImageCrop[InverseImagePyramid[pyr,Automatic,Floor[scaledims]],{Round[320Power[2,-FractionalPart@Log[2,scale]]]}],{320}]],{s,0,4.81538329581354}]

Out[5]=

Wolfram Language Example Repository

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Efficient Zooming Using Multiscale Pyramids

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