Filter: openfx.eu.cimg.EdgeDetect

Plugin Information

title: EdgeDetectCImg
media types: Video experimental
description: Perform edge detection by computing the image gradient magnitude. Optionally, edge detection can be preceded by blurring, and followed by erosion and thresholding. In most cases, EdgeDetect is followed a Grade node to extract the proper edges and generate a mask from these.

For color or multi-channel images, several edge detection algorithms are proposed to combine the gradients computed in each channel:

  • Separate: the gradient magnitude is computed in each channel separately, and the output is a color edge image.
  • RMS: the RMS of per-channel gradients magnitudes is computed.
  • Max: the maximum per-channel gradient magnitude is computed.
  • Tensor: the tensor gradient norm [1].

References:

  • [1] Silvano Di Zenzo, A note on the gradient of a multi-image, CVGIP 33, 116-125 (1986). http://people.csail.mit.edu/tieu/notebook/imageproc/dizenzo86.pdf

CImg is a free, open-source library distributed under the CeCILL-C (close to the GNU LGPL) or CeCILL (compatible with the GNU GPL) licenses. It can be used in commercial applications (see http://cimg.eu).

version: 2
creator: mr.fantastic mrfantastic@firemail.cc
license: GPLv2
URL: https://openeffects.org/

Parameters

NatronOfxParamProcessR

title: R
description: Process red component.
type: boolean
readonly: no
required: no
animation: yes
default: 1

NatronOfxParamProcessG

title: G
description: Process green component.
type: boolean
readonly: no
required: no
animation: yes
default: 1

NatronOfxParamProcessB

title: B
description: Process blue component.
type: boolean
readonly: no
required: no
animation: yes
default: 1

NatronOfxParamProcessA

title: A
description: Process alpha component.
type: boolean
readonly: no
required: no
animation: yes
default: 0

filter

title: Filter
description: Edge detection filter. If the blur size is not zero, it is used as the kernel size for quasi-Gaussian, Gaussian, box, triangle and quadratic filters. For the simple, rotation-invariant and Sobel filters, the image is pre-blurred with a Gaussian filter.
type: string
readonly: no
required: no
animation: yes
default: Gaussian
values:

  • Simple
  • Sobel
  • Rotation Invariant
  • Quasi-Gaussian
  • Gaussian
  • Box
  • Triangle
  • Quadratic

multiChannel

title: Multi-Channel
description: Operation used to combine multi-channel (e.g. color) gradients into an edge detector. This parameter has no effect if a single channel (e.g. alpha) is processed.
type: string
readonly: no
required: no
animation: yes
default: Tensor
values:

  • Separate
  • RMS
  • Max
  • Tensor

blurSize

title: Blur Size
description: Size of the blur kernel applied before edge detection.
type: float
readonly: no
required: no
animation: yes
minimum: 0
maximum: 100
default: 0

erodeSize

title: Erode Size
description: Size of the erosion performed after edge detection.
type: float
readonly: no
required: no
animation: yes
minimum: -10
maximum: 10
default: 0

nms

title: Non-Maxima Suppression
description: Perform non-maxima suppression (after edge detection and erosion): only values that are maximal in the direction orthogonal to the contour are kept. For multi-channel images, the contour direction estimation depends on the multi-channel operation.
type: boolean
readonly: no
required: no
animation: yes

expandRoD

title: Expand RoD
description: Expand the source region of definition by 1.5size (3.6sigma).
type: boolean
readonly: no
required: no
animation: yes
default: 1

premult

title: (Un)premult
description: Divide the image by the alpha channel before processing, and re-multiply it afterwards. Use if the input images are premultiplied.
type: boolean
readonly: no
required: no
animation: yes

maskInvert

title: Invert Mask
description: When checked, the effect is fully applied where the mask is 0.
type: boolean
readonly: no
required: no
animation: yes

mix

title: Mix
description: Mix factor between the original and the transformed image.
type: float
readonly: no
required: no
animation: yes
minimum: 0
maximum: 1
default: 1

mlt_origin

title: Top-Left Origin
description: Set to 1 to use MLT top-left image origin instead of the OFX bottom-left origin. Use for plugins that crash or produce incorrect output with negative row bytes.
type: boolean
readonly: no
required: no
minimum: 0
maximum: 1
default: 0
widget: checkbox

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