Function opencv::imgproc::filter_2d

pub fn filter_2d(
    src: &dyn ToInputArray, 
    dst: &mut dyn ToOutputArray, 
    ddepth: i32, 
    kernel: &dyn ToInputArray, 
    anchor: Point, 
    delta: f64, 
    border_type: i32
) -> Result<()>

Convolves an image with the kernel.

The function applies an arbitrary linear filter to an image. In-place operation is supported. When the aperture is partially outside the image, the function interpolates outlier pixel values according to the specified border mode.

The function does actually compute correlation, not the convolution:

That is, the kernel is not mirrored around the anchor point. If you need a real convolution, flip the kernel using #flip and set the new anchor to (kernel.cols - anchor.x - 1, kernel.rows - anchor.y - 1).

The function uses the DFT-based algorithm in case of sufficiently large kernels (~11 x 11 or larger) and the direct algorithm for small kernels.

Parameters

• src: input image.
• dst: output image of the same size and the same number of channels as src.
• ddepth: desired depth of the destination image, see @ref filter_depths "combinations"
• kernel: convolution kernel (or rather a correlation kernel), a single-channel floating point matrix; if you want to apply different kernels to different channels, split the image into separate color planes using split and process them individually.
• anchor: anchor of the kernel that indicates the relative position of a filtered point within the kernel; the anchor should lie within the kernel; default value (-1,-1) means that the anchor is at the kernel center.
• delta: optional value added to the filtered pixels before storing them in dst.
• borderType: pixel extrapolation method, see #BorderTypes

See also

sepFilter2D, dft, matchTemplate

C++ default parameters

• anchor: Point(-1,-1)
• delta: 0
• border_type: BORDER_DEFAULT