Method and apparatus for providing video mosaic effects

Claim 3

A method according to claim 1, wherein the second video signal comprises a stream of digital words and step (b) is accomplished by writing the second video signal into a first random access memory in line-by-line sequence and reading digital words from the first random access memory in col­umn-by-column sequence, whereby the effective scan­ning direction is rotated through 90 degrees, and the method further comprises writing the fourth video signal into a second random access memory in column-by-column sequence and reading digital words from the second random access memory in line-by- line sequence so as to generate a fifth video signal.

Claim 4

A method according to claim 1, further comprising rotating the effective scanning direc­tion of the fourth video signal through a predeter­mined angle so as to generate a fifth video signal.

Claim 5

A method according to claim 1, wherein the input video signal is a stream of digital data words occurring at a uniform clock rate, and the sample and hold operation is carried out on the input video signal by receiving each digital data word of the stream and either outputting that word or outputting a word that was previously received and held, the number of periods of the clock rate for which a first previously received and held word is outputted being different from the number of periods for which a second previously received and held word is outputted.

Claim 6

A method according to claim 1, comprising carrying out the sample and hold operation on the input video signal synchronously with the lines of the input video signal.

Claim 7

A method according to claim 1, wherein the second video signal is a stream of digital data words and step (b) is accomplished by writing the second video signal into a random access memory in line-by-line sequence and reading digital words from the random access memory into column-by-column sequence at a uniform clock rate, and the sample and hold operation on the third video signal is carried out by receiving each digital data word from the random access memory and either outputting that word or outputting a word that was previously received and held, the number of periods of the clock rate for which a first previously received and held word is outputted being different from the number of periods for which a second previously received and held word is outputted.

Claim 8

A method according to claim 1, wherein the third video signal occurs in a succession of time slots, and the method comprises carrying out the sample and hold operation on the third video signal synchronously with the third video signal.

Claim 9

Apparatus for processing a raster scan input video signal, comprising a first sample and hold for sampling the video signal and generating a second video signal, means for rotating the effec­tive scanning direction of the second video signal through a predetermined angle so as to generate a third video signal, and a second sample and hold for sampling the third video signal and generating a fourth video signal.

Claim 10

Apparatus for processing a raster scan input video signal, comprising a first sample and hold for sampling the video signal and generating a second video signal, means for rotating the effec­tive scanning direction of the second video signal through a predetermined angle so as to generate a third video signal, and a second sample and hold for sampling the third video signal and generating a fourth video signal.

Claim 11

Apparatus according to claim 8, wherein the second video signal in digital form and the means for rotating the effective scanning direction of the second video signal comprise a random access memory, means for writing the second video signal into the random access memory in line-by-line sequence, and means for reading digital words from the random access memory in column-by-column sequence.

Claim 12

Apparatus according to claim 9, wherein the fourth video signal is in digital form, and further comprising a second random access memory, means for writing the fourth video signal into the second random access memory in column-by-column sequence, and means for reading digital words from the second random access memory in line-by-line sequence.

Claim 13

Apparatus according to claim 8, wherein the input video signal is a stream of digital words occurring at a uniform clock rate and the first sample and hold has a first state in which it receives a digital word of the stream and outputs that word and a second state in which it receives a digital word of the stream and outputs a word that was previously received and held, the first sample and hold being placed in its first or second state in dependence upon a sampling signal provided by a sampling signal generator.

Claim 14

Apparatus according to claim 11, wherein the sampling signal generator is operative to allow the number of periods of the clock rate for which a first previously received and held word is output­ted to be different from the number of periods for which a second previously received and held word is outputted.

Claim 15

Apparatus according to claim 11, wherein the sampling signal generator is operative to pro­vide a sampling signal that is synchronous with the input video signal.

Claim 16

Apparatus according to claim 8, wherein the third video signal is a stream of digital words occurring at a uniform clock rate and the second sample and hold has a first state in which it receives a digital word of the stream and outputs that word and a second state in which it receives a digital word of the stream and output s a word that was previously received and held, the second sample and hold being placed in its first or second state in dependence upon a sampling signal provided by a sampling signal generator.

Claim 17

Apparatus according to claim 11, wherein the second video signal is in digital form and the means for rotating the effective scanning direction of the second video signal comprise a random access memory, means for writing the second video signal into the random access memory in line-by-line se­quence, and means for reading digital words from the random access memory in column-by-column se­quence at a uniform clock rate, and wherein the sampling signal generator is operative to allow the number of periods of the clock rate for which a first previously received and held word is output­ted to be different from the number of periods for which a second previously received and held word is outputted.

Claim 18

Apparatus according to claim 15, wherein the sampling signal generator is operative to pro­vide a sampling signal that is synchronous with the input video signal.