Contrast Enhancement Using the Laplacian-of-a-Gaussian Filter

A method of contrast enhancement for digital images is provided. As the method uses the LoG (Laplacian-of-a-Gaussian) filter, it is not significantly sensitive to noise. It is easy to develop this linear method when the Marr-Hildreth edge-detection technique has already been applied. LoG is roughly a bandpass filter.Therefore, only a single filter is required to enhance frequencies in one range. To enhance several frequency ranges, several standard deviation coefficients σ must be chosen for LoG convolutions. Progressive contrast ameliorations are obtained in this case. A description, an implementation, an estimate of efficiency, and a comparison with other methods are presented.