CrossingDetect

CrossingDetect[image] gives a binary image in which white pixels correspond to the zero crossings in image.

CrossingDetect[image,delta] treats values in image that are smaller in absolute value than delta as zero.

CrossingDetect[array,…] gives a binary sparse array in which 1 corresponds to zero crossings in array.

Examples

Detect zero crossings in an image:

img = LaplacianGaussianFilter[ExampleData[{"TestImage", "Lena"}], 2];
CrossingDetect[img]
(* Image[...] *)

Please visit the official Wolfram Language Reference for more details.