Function opencv::imgproc::sobel

pub fn sobel(
    src: &dyn ToInputArray, 
    dst: &mut dyn ToOutputArray, 
    ddepth: i32, 
    dx: i32, 
    dy: i32, 
    ksize: i32, 
    scale: f64, 
    delta: f64, 
    border_type: i32
) -> Result<()>

Calculates the first, second, third, or mixed image derivatives using an extended Sobel operator.

In all cases except one, the separable kernel is used to calculate the derivative. When , the or kernel is used (that is, no Gaussian smoothing is done). ksize = 1 can only be used for the first or the second x- or y- derivatives.

There is also the special value ksize = #CV_SCHARR (-1) that corresponds to the Scharr filter that may give more accurate results than the Sobel. The Scharr aperture is

for the x-derivative, or transposed for the y-derivative.

The function calculates an image derivative by convolving the image with the appropriate kernel:

The Sobel operators combine Gaussian smoothing and differentiation, so the result is more or less resistant to the noise. Most often, the function is called with ( xorder = 1, yorder = 0, ksize = 3) or ( xorder = 0, yorder = 1, ksize = 3) to calculate the first x- or y- image derivative. The first case corresponds to a kernel of:

The second case corresponds to a kernel of:

Parameters

• src: input image.
• dst: output image of the same size and the same number of channels as src .
• ddepth: output image depth, see @ref filter_depths "combinations"; in the case of 8-bit input images it will result in truncated derivatives.
• dx: order of the derivative x.
• dy: order of the derivative y.
• ksize: size of the extended Sobel kernel; it must be 1, 3, 5, or 7.
• scale: optional scale factor for the computed derivative values; by default, no scaling is applied (see #getDerivKernels for details).
• delta: optional delta value that is added to the results prior to storing them in dst.
• borderType: pixel extrapolation method, see #BorderTypes

See also

Scharr, Laplacian, sepFilter2D, filter2D, GaussianBlur, cartToPolar

C++ default parameters

• ksize: 3
• scale: 1
• delta: 0
• border_type: BORDER_DEFAULT