Acorn Acorn 5

Blur Filters



Many of the filter definitions below come directly from Apple’s core image filter reference.  


Background Blur:  Blurs the background using the input image as a mask.  Needs at least one layer below it to work.  See video tutorial:  Background Blur Filter.



 blur_filters0.png

Original

box blur.acorn

Box Blur

disc blur.acorn

Disc Blur

Gaussian blur.acorn


Gaussian Blur

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Motion Blur

zoom blur.acorn

Zoom Blur


Box Blur:  Blurs an image using a box-shaped convolution kernel.  Use a slider control to modify the radius of blur.


Disc Blur:  Blurs an image using a disc-shaped convolution kernel.  Use a slider control to modify the radius of blur.


Gaussian Blur:  Spreads source pixels by an amount specified by a Gaussian distribution. Use a slider control to modify the radius of blur.  A drop down menu offers the option to ‘clamp’ to prevent transparent pixels from outside your layer entering the blur.  


Masked Variable Blur:  Blurs the source image according to the brightness levels in a mask image.  Shades of gray in the mask image vary the blur radius from zero (where the mask image is black) to the radius specified in the radius field (where the mask image is white).  Drag and drop an image into the mask field.  


Motion Blur:  Blurs an image to simulate the effect of using a camera that moves a specified angle and distance while capturing the image.


Zoom Blur:  Simulates the effect of zooming the camera while capturing the image.  


Median Filter:  Computes the median value for a group of neighboring pixels and replaces each pixel value with the median.  The effect is to reduce noise.  There are no parameters to adjust.


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Original

median filter.acorn

Median Filter



Noise Reduction:  Reduces noise using a threshold value to define what is considered noise.  Small changes in luminance below that value are considered noise and get a noise reduction treatment, which is a local blur.  Changes above the threshold value are considered edges, so they are sharpened.  


blur_filters8.jpg 

Original 

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Sharpness increased



Radial Gradient Blur: Creates a radial blur similar to a vignette effect.


filters examples.jpg   

radial gradient blur.acorn