ImageScan

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`ImageScan`

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ImageScan[f,image]

evaluates f applied to each pixel of image in turn.

Details and Options

The channel values supplied to f are normally in the range 0 to 1, regardless of the underlying type used in the Image object.
ImageScan[f,image] discards the results of applying f to the pixels in image. Unlike ImageApply, ImageScan does not build up a new image and returns Null.
ImageScan is useful in carrying out an operation on parts of expressions where the operation has a "side effect", such as making an assignment.
ImageScan works on images with any number of channels.
You can also use Throw to exit from ImageScan. »
ImageScan traverses the pixels of image in a row-wise order from left to right.
ImageScan has the option Interleaving, which specifies whether f should be applied to individual channel values or to the complete list of channel values for a given pixel. The default setting is Interleaving->True.
With the setting Masking->roi, a region of interest to be scanned can be specified.
ImageScan works with Image3D objects.

Examples

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Basic Examples (5)Summary of the most common use cases

Scan pixels of a grayscale image:

In[1]:=1

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https://wolfram.com/xid/0enzd2s6c-dnik5q

Scan pixels of a color image:

In[1]:=1

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https://wolfram.com/xid/0enzd2s6c-jlt884

Scan pixels of a 3D image:

In[1]:=1

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https://wolfram.com/xid/0enzd2s6c-vno865

Count the number of white pixels in an image:

In[1]:=1

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https://wolfram.com/xid/0enzd2s6c-6u9yga

In[2]:=2

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https://wolfram.com/xid/0enzd2s6c-lby2ph

Out[2]=2

Compute the mean pixel value:

In[1]:=1

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https://wolfram.com/xid/0enzd2s6c-wa4p1o

In[2]:=2

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https://wolfram.com/xid/0enzd2s6c-gykosu

Out[2]=2

Generalizations & Extensions (1)Generalized and extended use cases

Throw works inside ImageScan:

In[1]:=1

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https://wolfram.com/xid/0enzd2s6c-k2o7sz

Out[1]=1

Options (4)Common values & functionality for each option

Interleaving (2)

By default, lists of channel values are scanned:

In[1]:=1

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https://wolfram.com/xid/0enzd2s6c-racuwu

Using Interleaving->False, individual channel values can be scanned:

In[2]:=2

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https://wolfram.com/xid/0enzd2s6c-q6zrb0

The interleaving setting does not affect the traversal of a single-channel image:

In[1]:=1

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https://wolfram.com/xid/0enzd2s6c-nutx93

In[2]:=2

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https://wolfram.com/xid/0enzd2s6c-6dgpt3

Masking (2)

By default, all image pixels are scanned:

In[1]:=1

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https://wolfram.com/xid/0enzd2s6c-in8vnm

Out[3]=3

Scan only the pixels specified by the mask:

In[4]:=4

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https://wolfram.com/xid/0enzd2s6c-pmojdk

Out[6]=6

Compute the mean color of the Spikey:

In[1]:=1

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https://wolfram.com/xid/0enzd2s6c-7e50qn

Out[1]=1

Create a disk of the computed mean color:

In[2]:=2

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https://wolfram.com/xid/0enzd2s6c-ot4yyo

Out[2]=2

Mean color computed without masking:

In[3]:=3

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https://wolfram.com/xid/0enzd2s6c-u3vli9

Out[3]=3

Properties & Relations (1)Properties of the function, and connections to other functions

ImageScan does the same as ImageApply, but without returning a result:

In[1]:=1

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https://wolfram.com/xid/0enzd2s6c-54c0y8

In[2]:=2

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https://wolfram.com/xid/0enzd2s6c-svhosm

Out[2]=2

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