ee.Kernel.laplacian4

  • Creates a 3x3 kernel for edge detection using the Laplacian-4 operator.

  • The kernel can be scaled using the magnitude argument and normalized using the normalize argument.

  • The default kernel values are: [[0, 1, 0], [1, -4, 1], [0, 1, 0]].

 Generates a 3x3 Laplacian-4 edge-detection kernel.

UsageReturns
ee.Kernel.laplacian4(magnitude, normalize)Kernel
ArgumentTypeDetails
magnitudeFloat, default: 1Scale each value by this amount.
normalizeBoolean, default: falseNormalize the kernel values to sum to 1.

Examples

Code Editor (JavaScript)

print('A Laplacian-4 kernel', ee.Kernel.laplacian4());

/**
 * Output weights matrix
 *
 * [0,  1, 0]
 * [1, -4, 1]
 * [0,  1, 0]
 */

Python setup

See the Python Environment page for information on the Python API and using geemap for interactive development.

import ee
import geemap.core as geemap

Colab (Python)

from pprint import pprint

print('A Laplacian-4 kernel:')
pprint(ee.Kernel.laplacian4().getInfo())

#  Output weights matrix

#  [0,  1, 0]
#  [1, -4, 1]
#  [0,  1, 0]