| edges {magick} | R Documentation |
Edge / Line Detection
Description
Best results are obtained by finding edges with image_canny() and
then performing Hough-line detection on the edge image.
Usage
image_edge(image, radius = 1)
image_canny(image, geometry = "0x1+10%+30%")
image_hough_draw(
image,
geometry = NULL,
color = "red",
bg = "transparent",
size = 3,
overlay = FALSE
)
image_hough_txt(image, geometry = NULL, format = c("mvg", "svg"))
Arguments
image |
magick image object returned by |
radius |
edge size in pixels |
geometry |
geometry string, see details. |
color |
a valid color string such as
|
bg |
background color |
size |
size in points to draw the line |
overlay |
composite the drawing atop the input image. Only for |
format |
output format of the text, either |
Details
For Hough-line detection, the geometry format is {W}x{H}+{threshold}
defining the size and threshold of the filter used to find 'peaks' in
the intermediate search image. For canny edge detection the format is
{radius}x{sigma}+{lower%}+{upper%}. More details and examples are
available at the imagemagick website.
See Also
Other image:
_index_,
analysis,
animation,
attributes(),
color,
composite,
defines,
device,
editing,
effects(),
fx,
geometry,
morphology,
ocr,
options(),
painting,
segmentation,
transform(),
video
Examples
if(magick_config()$version > "6.8.9"){
shape <- demo_image("shape_rectangle.gif")
rectangle <- image_canny(shape)
rectangle |> image_hough_draw('5x5+20')
rectangle |> image_hough_txt(format = 'svg') |> cat()
}