ColorQuantize
ImageData
ImageTake
FileSize
Export

Creative Arts
Image Processing

Experiment with Color Quantization and Compression with GIF Export

Use color quantization to improve image export and compare different quantization methods

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Consider an image:

In[1]:=

img=ResourceData["Example""Experiment with Color Quantization and Compression with GIF Export","Image"]

Out[1]=

Calculate how many different colors are in the picture:

In[2]:=

Length@Union@Flatten[ImageData[img],1]

Out[2]=

31944

Increasing the speed and quality of color quantization impacts export to image file formats such as "GIF" that perform quantization. Export the current image to GIF and check the size of the output file:

In[3]:=

FileSize[Export["file.gif",img]]

Out[3]=

53.741

Apply

ColorQuantize

to reduce the number of colors in the image with minimal quality loss:

In[4]:=

imgQuantized=ColorQuantize[img,64]

Out[4]=

Check to see that the resulting image uses only 64 different colors:

In[5]:=

Length@Union@Flatten[ImageData[imgQuantized],1]

Out[5]=

Quantization decreases the file size when exporting to GIF:

In[6]:=

FileSize[Export["file.gif",imgQuantized]]

Out[6]=

26.717

Use

ImageTake

to zoom into a small region of the image to see the difference between the original image and the image after quantization:

In[7]:=

GraphicsRowImageImageTake#,

,

...

&/@{img,imgQuantized}

Out[7]=

Explore Other Quantization Methods
(3)

Next consider other methods of quantization and different number of colors in the resulting image:

In[1]:=

methods={"MinVariance","MedianCut","Octree"};paletteSizes={2,4,8};

Apply the color quantization to the image using these settings and compare the results:

In[2]:=

TableFormTableImageColorQuantize[img,p,Methodm],

...

,{m,methods},{p,paletteSizes},

table headings



Out[2]//TableForm=

	2 colors	4 colors	8 colors
MinVariance
MedianCut
Octree

For smaller palette size, consider using a predefined set of colors and assign one of these colors to each pixel to best resemble the original image:

In[3]:=

ColorQuantizeimg,



Out[3]=

Related Symbols

ColorQuantize
ImageData
ImageTake
FileSize
Export

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Contributed by: Wolfram Staff

Experiment with Color Quantization and Compression with GIF Export

Explore Other Quantization Methods (3)

Related Symbols

Publisher Information

Explore Other Quantization Methods
(3)