Type Method

noiseReductionFilter

Reduces noise by sharpening the edges of objects.

Declaration

+ (CIFilter<CINoiseReduction> *)noiseReductionFilter;

Return Value

The blurred image.

Discussion

This method applies the noise reduction filter to an image. The effect calculates changes in luminance below the noise level and locally blurs the area. Values above the threshold are determined to be edges, and become sharpened.

The morphology noise reduction filter uses the following properties:

noiseLevel

A float representing the amount of noise reduction as an NSNumber.

sharpness

A float representing the sharpness of the final image as an NSNumber.

inputImage

A CIImage representing the input image to apply the filter to.

The following code creates a filter that reduces noise in the input image:

    func noiseReduction(inputImage: CIImage) -> CIImage? {

        let noiseReductionfilter = CIFilter.noiseReduction()
        noiseReductionfilter.inputImage = inputImage
        noiseReductionfilter.noiseLevel = 0.2
        noiseReductionfilter.sharpness = 0.4
        return noiseReductionfilter.outputImage
    }
Two photographs of a beach at sunset with multiple palm trees. The photo on the left is in focus. In the photo on the right, a noise reduction filter has been applied, and the edges of the objects such as the palm fronds have more sharpness and detail.

See Also

Filters

+ bokehBlurFilter

Applies a bokeh effect to an image.

+ boxBlurFilter

Applies a square-shaped blur to an area of an image.

+ discBlurFilter

Applies a circle-shaped blur to an area of an image.

+ gaussianBlurFilter

Blurs an image with a Gaussian distribution pattern.

+ maskedVariableBlurFilter

Blurs a specified portion of an image.

+ medianFilter

Calculates the median of an image to refine detail.

+ morphologyGradientFilter

Detects and highlights edges of objects.

+ morphologyMaximumFilter

Blurs a circular area by enlarging contrasting pixels.

+ morphologyMinimumFilter

Blurs a circular area by reducing contrasting pixels.

+ morphologyRectangleMaximumFilter

Blurs a rectangular area by enlarging contrasting pixels.

+ morphologyRectangleMinimumFilter

Blurs a rectangular area by reducing contrasting pixels.

+ motionBlurFilter

Creates motion blur on an image.

+ zoomBlurFilter

Creates a zoom blur centered around a single point on the image.