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# Reduction Filters

Create statistical information about an image.

## Topics

### Filters

[`+  areaAverageFilter`](/documentation/CoreImage/CIFilter-swift.class/areaAverage())

Returns a 1 x 1 pixel image that contains the average color for the region of interest.

[`+  areaHistogramFilter`](/documentation/CoreImage/CIFilter-swift.class/areaHistogram())

Returns a histogram of a specified area of the image.

[`+  areaLogarithmicHistogramFilter`](/documentation/CoreImage/CIFilter-swift.class/areaLogarithmicHistogram())

Returns a logarithmic histogram of a specified area of the image.

[`+  areaMaximumFilter`](/documentation/CoreImage/CIFilter-swift.class/areaMaximum())

Calculates the maximum color components of a specified area of the image.

[`+  areaMaximumAlphaFilter`](/documentation/CoreImage/CIFilter-swift.class/areaMaximumAlpha())

Finds the pixel with the highest alpha value.

[`+  areaMinimumFilter`](/documentation/CoreImage/CIFilter-swift.class/areaMinimum())

Calculates the minimum color component values for a specified area of the image.

[`+  areaMinimumAlphaFilter`](/documentation/CoreImage/CIFilter-swift.class/areaMinimumAlpha())

Calculates the pixel within a specified area that has the smallest alpha value.

[`+  areaMinMaxFilter`](/documentation/CoreImage/CIFilter-swift.class/areaMinMax())

Calculates minimum and maximum color components for a specified area of the image.

[`+  areaMinMaxRedFilter`](/documentation/CoreImage/CIFilter-swift.class/areaMinMaxRed())

Calculates the minimum and maximum red component value.

[`+  columnAverageFilter`](/documentation/CoreImage/CIFilter-swift.class/columnAverage())

Calculates the average color for a specified column of an image.

[`+  histogramDisplayFilter`](/documentation/CoreImage/CIFilter-swift.class/histogramDisplay())

Generates a histogram map from the image.

[`+  KMeansFilter`](/documentation/CoreImage/CIFilter-swift.class/kMeans())

Applies the k-means algorithm to find the most common colors in an image.

[`+  rowAverageFilter`](/documentation/CoreImage/CIFilter-swift.class/rowAverage())

Calculates the average color for the specified row of pixels in an image.

### Protocols

[`CIAreaAverage`](/documentation/CoreImage/CIAreaAverage)

[`CIAreaHistogram`](/documentation/CoreImage/CIAreaHistogram)

[`CIAreaLogarithmicHistogram`](/documentation/CoreImage/CIAreaLogarithmicHistogram)

[`CIAreaMaximum`](/documentation/CoreImage/CIAreaMaximum)

[`CIAreaMaximumAlpha`](/documentation/CoreImage/CIAreaMaximumAlpha)

[`CIAreaMinMax`](/documentation/CoreImage/CIAreaMinMax)

[`CIAreaMinMaxRed`](/documentation/CoreImage/CIAreaMinMaxRed)

[`CIAreaMinimum`](/documentation/CoreImage/CIAreaMinimum)

[`CIAreaMinimumAlpha`](/documentation/CoreImage/CIAreaMinimumAlpha)

[`CIAreaReductionFilter`](/documentation/CoreImage/CIAreaReductionFilter)

[`CIColumnAverage`](/documentation/CoreImage/CIColumnAverage)

[`CIHistogramDisplay`](/documentation/CoreImage/CIHistogramDisplay)

[`CIKMeans`](/documentation/CoreImage/CIKMeans)

[`CIRowAverage`](/documentation/CoreImage/CIRowAverage)


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