Abstract: 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.

Abstract: To capture an image, the image sensing period of this image is subdivided into a plurality of successive illumination periods, and the value which is assigned to each pixel to capture the image is the sum of the integrals of intensity of illumination of this pixel over each of said successive illumination periods. According to the invention, this sum is weighted by an apodization function in order to emulate a mechanical shutter. Temporal aliasing issues and temporal ringing artifacts of digital imaging are prevented or at least limited.

Abstract: 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.

Abstract: 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.

Abstract: The invention relates to a method of processing source images which is intended to combat their copying by a camcorder or a camera during their display, for example in a cinema hall. The source image sequence represents a scene. According to the invention, the method comprises the following steps: detection, in the said scene, of at least one zone corresponding to an object of the scene, selection of the entirety of the pixels of the said at least one zone in at least one source image of the sequence; and processing of the said at least one source image to modify the colour of the selected pixels or the spectral composition of the light emitted by the selected pixels so that the perceived colour of the selected pixels is unchanged in the processed source image with respect to the source image.

Abstract: The invention relates to a projection system for displaying at least one visual image based on three primary colours, comprising a signal processing unit for converting said visual image into at least a visual image based on four primary colours, a frequency band being associated to each colour primary, first display means for displaying three first primary colours of said visual image on a screen and second display means for displaying at least the fourth primary colour of said visual image on said screen. According to the invention, the system further comprises optical filtering means that are adapted to enhance the separation between the frequency spectrum of the first three primary colours of the first display means and the frequency spectrum of the at least fourth primary colour of the second display means. Application to anti-camcorder systems.

Abstract: 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.

Abstract: The invention concerns a method for processing a sequence of source pictures to generate artifacts due to aliasing when these source pictures are captured by a video capturing device. This method comprises a first time modulation step for modulating temporally at a first modulation frequency the brightness of pixels of each picture of the sequence around a brightness to be displayed for said picture. According to an important feature of the invention, the method further comprises a second time modulation step for modulating temporally at a second modulation frequency different from the first modulation frequency the brightness of pixels of each picture of the sequence around a brightness value to be displayed for said picture, the first and second modulation frequencies being determined in order not to be visible to the human eye and contributing to generate aliasing artifact at a predetermined aliasing frequency.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: The present invention relates to a processing device of a sequence of video images intended to be displayed by a digital cinema projection system, a projection system for the digital cinema and a video signal designed to be used by such a system. The use of an anti-camcorder method against copying films is generally carried out entirely in the digital cinema projection system. However, this method requires complex video processing and costly means in the projection system. According to the invention, it is proposed to carry out part of the video processing at the level of the post-production of the video sequence and to save the result of this “pre-processing” in the form of metadata. The remaining part of the video processing is carried out from this metadata in the video projection system.

Abstract: 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.

Abstract: 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.