System for providing private viewing of multimedia contents, said system comprising: - a display comprising a plurality of pixels; - an image signal generator which generates an original image signal representative of an original image to be displayed on said display, said original image signal comprising Red, Green and Blue colour data components; - signal modifying means which produces a modified image starting from said original image; - extracting means for extracting said original image from said compound image displayed on the display; characterized in that said system further comprises: - a memory apt to receive and record an original frame sequence (N, N+1, N+2) corresponding to the original image signal generated by said image signal generator at a first speed corresponding to a clock frequency; - a duplicating element apt to read said memory at a second speed corresponding to a speed which is the double of said clock frequency, said duplicating element being apt to duplicate said original frame sequence (N, N+1, N+2) in order to send to said signal modifying means a first (2N, 2(N+1), 2(N+2)) and a second type of frame sequence (2N', 2(N'+1 2(N'+2)); Wherein said modifying means: - mix, on a pixel-by-pixel basis, each original image signal transmitted from they image signal generator 3 with at least one corresponding modified image signal component thereof, in order to generate a compound image signal to bye sent to said display; - comprise: - a plurality of first multiplexers (41R, 41G, 41B), each of said first multiplexers (41R, 41G, 41B) being apt to receive said first and second type of frame sequences of one of said Red, Green and Blue colour data components; - a plurality of complementing circuits (42R, 42G, 42B), each of said complementing circuits (42R, 42G, 42B) being associated to a respective first multiplexer (41R, 41G, 41B) for elaborating said second type frame sequence and producing a third type of frame sequence corresponding to a modifying (i.e. inverse and/or complementary) colour data component; - a plurality of second multiplexers (43R, 43G, 43B), each of said second multi plexers (43R, 43G, 43B) being associated to a respective first multiplexer (41R, 41G, 41B) for receiving said first type of frame sequence, and to a respective complementing circuits (42R, 42G, 42B) for receiving said third type of frame sequence, in order to send to the display a compound mixed image that is representative of said first and third type of frame sequence and results to be substantially neutral and featureless. - a display comprising a plurality of pixels; - an image signal generator which generates an original image signal representative of an original image to be displayed on said display, said original image signal comprising Red, Green and Blue colour data components; - signal modifying means which produces a modified image starting from said original image; - extracting means for extracting said original image from said compound image displayed on the display; - a memory apt to receive and record an original frame sequence (N, N+1, N+2) corresponding to the original image signal generated by said image signal generator at a first speed corresponding to a clock frequency; - a duplicating element apt to read said memory at a second speed corresponding to a speed which is the double of said clock frequency, said duplicating element being apt to duplicate said original frame sequence (N, N+1, N+2) in order to send to said signal modifying means a first (2N, 2(N+1), 2(N+2)) and a second type of frame sequence (2N', 2(N'+1 2(N'+2)); - mix, on a pixel-by-pixel basis, each original image signal transmitted from they image signal generator 3 with at least one corresponding modified image signal component thereof, in order to generate a compound image signal to bye sent to said display; - comprise: - a plurality of first multiplexers (41R, 41G, 41B), each of said first multiplexers (41R, 41G, 41B) being apt to receive said first and second type of frame sequences of one of said Red, Green and Blue colour data components; - a plurality of complementing circuits (42R, 42G, 42B), each of said complementing circuits (42R, 42G, 42B) being associated to a respective first multiplexer (41R, 41G, 41B) for elaborating said second type frame sequence and producing a third type of frame sequence corresponding to a modifying (i.e. inverse and/or complementary) colour data component; - a plurality of second multiplexers (43R, 43G, 43B), each of said second multi plexers (43R, 43G, 43B) being associated to a respective first multiplexer (41R, 41G, 41B) for receiving said first type of frame sequence, and to a respective complementing circuits (42R, 42G, 42B) for receiving said third type of frame sequence, in order to send to the display a compound mixed image that is representative of said first and third type of frame sequence and results to be substantially neutral and featureless.