Koninklijke Philips Corporation N.v.

Johan Gerard Willem Maria Janssen

Haiyan He

An edge detection technique combines a low-pass second derivative of an image signal, a low-pass first derivative of the image signal, and an estimation of edge frequency. The edge frequency estimation is preferably based on a ratio of a third to a first low-pass derivative of image signal. The image signal is preferably a luminance signal.

Method and apparatus for edge detection

Image enhancement is achieved by a combination of linear and non-linear techniques. The linear technique is preferably peaking, while the non-linear techniques is preferably LTI. The peaking is applied to non-edge areas of the image. The LTI is applied to edge areas of the image. LTI is of the sub-pixel variety. The image enhancement device is preferably part of a device for converting standard definition to high definition signals.

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Ossining, NY, United States of America

Johan Gerard Willem Maria Janssen