An Elementary Introduction to the Wolfram Language
10Images
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You can apply functions to images just like you apply functions to numbers or lists or anything else. The function ColorNegate that we saw in connection with colors also works on images, giving a negative image.
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You can make a table of the results of different amounts of blurring:
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ImageCollage puts images together:
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Theres lots of analysis one can do on images. For example, DominantColors finds a list of the most important colors in an image.
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Binarize makes an image black and white:
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Not surprisingly, the dominant colors in the result are black and white:
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Pick out edges in the original image:
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Its often convenient to do image processing interactively, creating interfaces using Manipulate. For example, Binarize lets you specify a threshold for what will be turned black as opposed to white. And often the best way to find the right threshold is just to interactively experiment with it.
Make an interface to adjust the threshold for binarizing an image:
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CurrentImage[ ] capture the current image from your computer, etc.
ColorNegate[ ] negate the colors in an image
Binarize[ ] convert an image to black and white
Blur[ , 5] blur an image
EdgeDetect[ ] detect the edges in an image
DominantColors[ ] get a list of dominant colors in an image
ImageCollage[{ , , }] put together images in a collage
ImageAdd[ , ] add color values of two images
10.1Color negate the result of edge detecting an image. (Use CurrentImage[ ] or any other image.) »
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10.2Use Manipulate to make an interface for blurring an image from 0 to 20. »
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10.3Make a table of the results from edge detecting an image with blurring from 1 to 10. »
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10.4Make an image collage of an image together with the results of blurring, edge detecting and binarizing it. »
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10.5Add an image to a binarized version of it. »
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10.6Create a Manipulate to display edges of an image as it gets blurred from 0 to 20. »
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10.7Image operations work on Graphics and Graphics3D. Edge detect a picture of a sphere. »
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10.8Make a Manipulate to make an interface for blurring a purple pentagon from 0 to 20. »
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10.9Create a collage of 9 images of disks, each with a random color. »
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10.10Use ImageCollage to make a combined image of spheres with hues from 0 to 1 in steps of 0.2. »
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10.11Make a table of blurring a disk by an amount from 0 to 30 in steps of 5. »
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10.12Use ImageAdd to add an image to an image of a disk. »
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10.13Use ImageAdd to add an image to an image of a red octagon. »
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+10.1Edge detect a binarized image. »
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+10.2Color negate the result of edge detecting an image of a regular pentagon. »
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+10.3Use ImageAdd to add an image to itself. »
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+10.4Use ImageAdd to add together the images of regular polygons with between 3 and 100 sides. »
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Instead of CurrentImage[], just get a test image using for example ExampleData[{"TestImage", "Mandrill"}].
What does the number in Blur mean?
Its the range of pixels that get blurred together.
How does Binarize decide whats black and whats white?
If you dont tell it a threshold, it will pick one based on analyzing the distribution of colors in the image.
 
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