摘要:
The present invention is in the field of Content protection, most particularly in cinema venues where camcorder acquisition followed by immediate illegal distribution creates important revenue losses for content owners. It is known that anti-camcorder systems using a color modulation can be circumvented by using low shutter speed in the camcorder. Today, the shutter speed is determined automatically by the camcorder as a function of the filmed video source. In automatic configurations, shutter speed self-adapts to either motion, or flicker detection, both of which taking into account brightness variations only. The proposed invention proposes a dual color/brightness modulation to defeat automatic shutter speed adjustment. For example, a color modulation at 50/60 Hz is carried out and a brightness modulation at a higher frequency 100/120 Hz is added to force the camcorder to work at a high shutter speed.
摘要:
A projector has at least four primary color components controlled to produce a metameric effect image which is not perceptible to the human optical system and is perceptible to a video recording device.
摘要:
The image is broken down into a breakdown color space. For each broken down source pixel, if a source point PS0j is used to represent the end of the color source vector OPS0j associated with said source pixel, component points P1j, P2j, . . . , Pkj, . . . , Pnj are used to represent the ends of the color component vectors OP1j, OP2j, . . . , OPkj, . . . , OPnj associated with the component pixels, if a limit sphere of radius LS0j is defined, centered on the point PS0j, then said breakdown is such that the following applies: PS0Pj1, PS0Pj2, PS0Pjk, . . . , PS0Pjn≧KS0j×LS0j, with KS0j≧0.5. The effectiveness of the scrambling is then significantly enhanced.
摘要:
The present invention is in the field of Content protection, most particularly in cinema venues where camcorder acquisition followed by immediate illegal distribution creates important revenue losses for content owners. It is known that anti-camcorder systems using a color modulation can be circumvented by using low shutter speed in the camcorder. Today, the shutter speed is determined automatically by the camcorder as a function of the filmed video source. In automatic configurations, shutter speed self-adapts to either motion, or flicker detection, both of which taking into account brightness variations only. The proposed invention proposes a dual color/brightness modulation to defeat automatic shutter speed adjustment. For example, a color modulation at 50/60 Hz is carried out and a brightness modulation at a higher frequency 100/120 Hz is added to force the camcorder to work at a high shutter speed.
摘要:
A projector has at least four primary color components controlled to produce a metameric effect image which is not perceptible to the human optical system and is perceptible to a video recording device.
摘要:
This invention relates to a method to select, in an input image, pixels that can be watermarked by replacing their colour by a metameric colour. It comprises the following steps: correct the input image by applying a predetermined gamma law, convert the input image into a ‘metameric’ image in which the colours of the input image pixels are replaced by metameric colours, simulate the capture of the input image and of the metameric image by a camcorder in order to generate respectively a captured input image and a captured metameric image, determine, in a colour space and for each pixel of the input image, the distance between the colour of said pixel in the captured input image and in the captured metameric image, and select the pixels of the input image for which the distance is greater than a threshold. The invention also concerns a watermarking method based on metamerism.
摘要:
The invention discloses a new modulation scheme to prevent illegal copy in movie theaters. None of the existing modulation schemes make the right assumptions to modelize a camcorder device. In such classical schemes, camcorders are always considered as sampling devices without taking into account the effects of shutter speed. The shutter of the camcorder is classically compared to a low-pass filter. As a result, modulation effects can be easily removed by setting up shutter speed to low values (low cutoff frequency). The right mathematical modelization of the shutter effect shows that, in the spectral domain, the behavior of the camcorder is close to a cardinal sine function with a main lobe and sidelobes. Consequently, according to the invention, it is proposed to select a modulation frequency that not only generates visual artifacts once recorded by the camcorder under shutter-free conditions, but that can also generate artifacts despite low shutter speed settings by going through sidelobe of the shutter spectrum.
摘要:
Method in which a component image associated with a primary color of green hue is processed in a suitable manner to reduce the spatial frequencies corresponding to the transition zones in this component image and in which a plurality of component images including the processed component image are successively displayed. Thanks to the invention, the color break-up defects are noticeably reduced. The invention applies especially to anti-piracy image display methods.
摘要:
The invention relates to a method for combating the copying of source pictures by means of a camera while they are being displayed, for example using a camcorder in a movie theatre. To this end, it is known, in classical projection systems, to modulate by a carrier wave the brightness of some pixels of the pictures. The frequency of the carrier wave is usually constant and generally half the refresh frequency. The main problem with such systems is that once a pirate has figured out what the modulation frequency is, he can configure his camcorder shutter to filter out this frequency and bypass the anti-camcorder method. According to the invention, the frequency of the carrier is changed at least once throughout the displaying of the sequence pictures or the movie, to defeat all camcorders standards (PAL/NTSC) and shutter configurations.
摘要:
The spatial frequency analysis contained in the compressed image is used not only for decompression of images but also for the selection of an appropriate gamut mapping algorithm. Computation resources are then saved because no specific spatial frequency analysis is required for the selection of an appropriate gamut mapping algorithm.