Box blur

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A box blur is an image filter in which each pixel in the resulting image has a value equal to the average value of its neighboring pixels in the input image. It is a form of low-pass ("blurring") filter and is a convolution.

Due to its property of using equal weights it can be implemented using a much simpler accumulation algorithm which is significantly faster than using a sliding window algorithm^[1].

Box blurs are frequently used to approximate a Gaussian blur^[2]. If applied 3 times on the same image it approximates the Gaussian kernel to within about 3%, yielding the same result as a quadratic convolution kernel.

[edit] See also

• Gaussian blur
• Bokeh

[edit] References