Calculates an Image Derivatives Using a Scharr Operator

scharr calculates the x or y derivative of an image using a Scharr operator.

Usage

scharr(image, dx = 1, dy = 0, scale = 1, target = "new", in_place = NULL)

Arguments

image

An Image object.

dx

Order of the x derivative. It can only take 2 values: 1 (the default) or 0. If dx=1 then dy must be zero.

dy

Order of the y derivative. It can only take 2 values: 1 or 0 (the default). If dy=1 then dx must be zero.

scale

The scale factor for the computed derivative values (default: 1).

target

The location where the results should be stored. It can take 3 values:

"new":: a new Image object is created and the results are stored inside (the default).
"self":: the results are stored back into image (faster but destructive).
An Image object:: the results are stored in another existing Image object. This is fast and will not replace the content of image but will replace that of target. Note that if target does not have the same dimensions, number of channels, and bit depth as image, an error may be thrown.

in_place

Deprecated. Use target instead.

Value

If target="new", the function returns an Image object. If target="self", the function returns nothing and modifies image in place. If target is an Image object, the function returns nothing and modifies that Image object in place.

Author

Simon Garnier, garnier@njit.edu

Examples

balloon <- image(system.file("sample_img/balloon1.png", package = "Rvision"))
balloon_scharr <- scharr(balloon)