Talk:Thresholding (image processing)

I believe the improved threshold should be: (||G2||*m1+||G1||*m2)/(||G2||+||G1||).

Shoul image thresholding redirect to this page? Albert Cruz 22:34, 1 July 2008 (UTC) Pikez33

Weighted average doesn't make sense

I removed the following:

Another approach is to calculate the new threshold in step four using the weighted average of $m_{1}$ and $m_{2}$: T’ = (||$G_{1}$||*$m_{1}$ + ||$G_{2}$||*$m_{2}$)/(||$G_{1}$||+||$G_{2}$||), where ||$G_{n}$|| is the number of pixels in $G_{n}$. This approach often gives a more accurate result.

because it appears to do nothing more than calculate the mean value of all the pixels, independent of the threshold value. The mean of $G_{1}$ pixels times the number of $G_{1}$ pixels is the sum of $G_{1}$ pixels. Same goes for $G_{2}$. The union of $G_{1}$ and $G_{2}$ is the whole image, so the sum of those products is the sum of all the pixels in the image and ||$G_{1}$|| + ||$G_{2}$ is the number of pixels in the image. Ergo, their quotient is the mean of all the pixels in the image.

Bryan Henderson 22:15, 20 May 2007 (UTC)