Determines blurriness of frames without altering the input frames.

Based on Marziliano, Pina, et al. "A no-reference perceptual blur metric." Allows for a block-based abbreviation.

The filter accepts the following options:

low, high

Set low and high threshold values used by the Canny thresholding algorithm.

The high threshold selects the "strong" edge pixels, which are then connected through 8-connectivity with the "weak" edge pixels selected by the low threshold.

low and high threshold values must be chosen in the range [0,1], and low should be lesser or equal to high.

Default value for low is 20/255, and default value for high is 50/255.

radius

Define the radius to search around an edge pixel for local maxima.

block_pct

Determine blurriness only for the most significant blocks, given in percentage.

block_width

Determine blurriness for blocks of width block_width. If set to any value smaller 1, no blocks are used and the whole image is processed as one no matter of block_height.

block_height

Determine blurriness for blocks of height block_height. If set to any value smaller 1, no blocks are used and the whole image is processed as one no matter of block_width.

planes

Set planes to filter. Default is first only.