IM (version 1.0)

calcCentroid: Calculate the centroid of a grayscale image

Description

Calculate the centroid of a grayscale image using geometric moments. The centroid is based on pixel intensity. The centroid, located at pixel coordinates (x0,y0) is calculated using the following equation: $$x0 = \frac{m_{10}}{m_{00}}$$ $$y0 = \frac{m_{10}}{m_{00}}$$ where $$m_{pq} = \sum_{1}^{N} \sum_{1}^{M} (x^p)(y^q)f(x,y)$$ N is the horizontal dimensionality of the image and M is the vertical dimensionality of the image. $$f(x,y)$$ is the pixel intensity of the pixel at location (x,y) in the image.

Usage

calcCentroid(I)

Arguments

I

An image represented as a 2-dimensional grayscale matrix.

Value

• numeric: (x0, y0)
• x0
  x-coordinate of centroid
• y0
  y-coordinate of centroid

References

Flusser, J., Suk, T., Zitova, B. Moments and Moment Invariants in Pattern Recognition. 2009. John Wiley & Sons Ltd. ISBN: 978-0-470-69987-4

See Also

Image,CmplxIm,OrthIm,polarXY

Examples

data(pirate)
I=rowSums(img,dims=2);
center= calcCentroid(I);