Horizontal and vertical transition level enhancement in a television system

Claim 2

Apparatus for providing horizontal enhancement of a television video image signal passing through a system including a video source (32), a degrading path (38) such as transmission or recording, and a display, the apparatus being characterised by horizontal domain low transition level detail processor means (34) connected between the video source (32) and the degrading path (38) for enhancing horizontal transitions below a first threshold level prior to passage of the signal through the degrading path (38), and horizontal domain large transition level enhancement processor means (46) connected between the degrading path (38) and the display for enhancing horizontal transitions above a second threshold level following passage of the signal through the degrading path (38).

Claim 3

Apparatus according to claim 1, comprising line doubler means (42) between the degrading path (38) and the display for doubling the number of scan lines within the signal.

Claim 4

Apparatus according to claim 2, comprising vertical domain transition enhancement processor means (48) between the line doubler means (42) and the display.

Claim 5

Apparatus according to claim 3, wherein the vertical domain transition enhancement processor means (48) comprises a combination of means for contour processing and for low level detail processing.

Claim 6

Apparatus according to any one of claims 1 to 4, wherein the first threshold level is about 40 IRE units and the second threshold level is about 20 IRE units.

Claim 7

A television signal processing system comprising a source (32) of video images for providing luminance and chrominance components of the video images by generating and putting out scan lines, encoder means (36) connected to encode the chrominance component and the luminance component into an encoded signal in accordance with a predetermined signal format, degrading path means (38) of the type such as transmission and recording through which the encoded signal is passed, and decoder means (40) connected to receive the encoded signal passed through the degrading path and to decode the signal in accordance with the predetermined signal format to produce luminance and chrominance components, which system is characterised by horizontal domain detail processor means (34) connected for boosting horizontal transitions of the luminance component put out by the source (32) below a predetermined threshold, line doubler means (42) connected to the decoder means (40) for doubling the number of decoded scan lines of the signal and for putting out scan line doubled luminance and chrominance components, and image processor means (44, 46, 48) connected to the line doubler means (42) and including horizontal domain transition high level enhancement processor means (46) for enhancing horizontal domain transitions having an amplitude above the predetermined threshold and further including vertical enhancement processor means (48) for enhancing vertical domain transitions in accordance with predetermined vertical domain enhancement criteria.

Claim 8

A television signal processing system comprising a source (32) of video images for providing luminance and chrominance components of the video images by generating and putting out scan lines, encoder means (36) connected to encode the chrominance component and the luminance component into an encoded signal in accordance with a predetermined signal format, degrading path means (38) of the type such as transmission and recording through which the encoded signal is passed, and decoder means (40) connected to receive the encoded signal passed through the degrading path and to decode the signal in accordance with the predetermined signal format to produce luminance and chrominance components, which system is characterised by horizontal domain detail processor means (34) connected for boosting horizontal transitions of the luminance component put out by the source (32) below a predetermined threshold, line doubler means (42) connected to the decoder means (40) for doubling the number of decoded scan lines of the signal and for putting out scan line doubled luminance and chrominance components, and image processor means (44, 46, 48) connected to the line doubler means (42) and including horizontal domain transition high level enhancement processor means (46) for enhancing horizontal domain transitions having an amplitude above the predetermined threshold and further including vertical enhancement processor means (48) for enhancing vertical domain transitions in accordance with predetermined vertical domain enhancement criteria.

Claim 9

A television signal processing system according to claim 6, wherein the predetermined threshold lies in a range between about 20 IRE units and about 40 IRE units.

Claim 10

A television signal processing system according to claim 6 or 7, wherein the predetermined vertical domain enhancement criteria comprise a combination of low level detail boost and contouring.