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# Feature Detection Keys

Keys used in the options dictionary for [`features(in:options:)`](/documentation/CoreImage/CIDetector/features(in:options:)).

## Topics

### Constants

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

An option for the display orientation of the image whose features you want to detect.

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

An option for whether Core Image will perform additional processing to recognize closed eyes in detected faces.

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

An option for whether Core Image will perform additional processing to recognize smiles in detected faces.

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

An option identifying the focal length in pixels used in capturing images to be processed by the detector.

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

An option specifying the aspect ratio (width divided by height) of rectangles to search for.

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

An option specifying whether to return feature information for components of detected features.


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