Abstract: Detection and deterrence of counterfeiting permits one to make legitimate color copies without introducing visual artifacts or experiencing substantial processing delays. We enable an efficient counterfeit deterrence by the use of an hierarchic detection scheme, in which the majority of documents are classified as free of suspicion using a simple algorithm that imposes a negligible computational burden. The remainder of documents, which are labeled as suspicious, receive analysis by one or more potentially complex detection algorithms. If the suspicious document is identified as being a secure document, this will lead to printing with selectively deteriorated service or complete denial of service. For one embodiment, the scheme uses a color look-up table (LUT) to detect a characteristic color (or colors) of frequently counterfeited documents and alters the characteristic color in the copies if a more accurate second test verifies that printing of a counterfeit is being attempted.

Abstract: The present invention is directed to methods and apparatus that partially encrypt an information data file. An exemplary method includes dividing the information file into a first file and a second file, wherein the second file includes content from the information file to preclude reconstruction of the information file using only the first file, and encrypting the second file. Additionally, the method provides for transmitting the first file and the encrypted second file from a first device to a second device.

Abstract: A method and apparatus is described for detection and deterrence of counterfeiting that permits one to make legitimate copies without introducing substantial visual artifacts or experiencing substantial processing delays by imposing a small, random, offset or jitter into the position upon a page where printing of a copy of a document begins. The jitter makes it extremely unlikely that the registration icons align when the secure document is copied. The misalignment of the icons signal that the copy is a counterfeit. In one implementation, the jitter is always introduced and, in another implementation, jitter is only introduced when counterfeiting is possible, or likely.

Abstract: A method and apparatus is described for detection and deterrence of counterfeiting that permits one to make legitimate color copies without introducing visual artifacts or experiencing substantial processing delays. The scheme detects a characteristic color of frequently counterfeited documents and alters the characteristic color in the copies. The scheme exploits the fact that conversion between color spaces is frequently accomplished using a color Look-Up Table (LUT). Because it represents no computational burden to alter the values in the LUT, we can efficiently modulate slightly the value of the characteristic color in a way that depends on the value of the counter. For example, at first even banknote green is rendered correctly. However, as the page uses more and more of the ink, a modulation function causes conversion to a darker value than the actual green requested.

Abstract: A method to reduce the distortion introduced by lossy compression of interpolated images. The interpolation represents a constraint. If the output of the compression algorithm does not satisfy the constraint then the estimate of the output can be improved by re-imposing the constraint. An alternating projection algorithm is used to impose both the interpolation constraint, and the requirement that the image compress to the observed compressed output. This involves finding the orthogonal projection alternately on the space of interpolated images, and on the set of images that quantize to the appropriate image produced by the compression algorithm. Although this algorithm is not restricted to the correction of errors in block coding schemes, the explicit introduction of the interpolation constraint allows this algorithm to outperform all other iterative algorithms that attempt only to remove blocking artifacts introduced by transform coders.

Abstract: A technique, referred to as area-based interpolation, performs image interpolation. The system determines a curve by the pixel value at a location by taking the integral of a curve over a small area, where the size of the area is determined by the sampling size of a sampling cell. When the image is resampled with respect to a sampling cell that has a finer spacing, the system integrates the polynomial using a finer integration area. In accordance with the invention, the relation between the reintegrated, resampled high resolution image and the low resolution image is a function of an up-sampler, followed by a linear filter. The coefficients of the filter are independent of the data, but are dependent on the family of curves used. If the system models by, for example, a third degree or fourth degree polynomial everywhere in the image, then that model determines the number of coefficients that are in the filter.

Abstract: A process and apparatus is described to improve the fidelity of compressed demosaiced images by decreasing the error introduced for a given compression ratio. Because (typically) two out of three of the color values at any location of the demosaiced image are interpolated, most of the loss can be concentrated into these values, so that the actual or measured data values have little loss. This is achieved by finding an interpolation of the data such that the original measured values suffer minimal loss in the lossy compression, while the loss for the other interpolated values may be arbitrarily large. Thus, rather than performing an interpolation first and accepting whatever loss the compression scheme (e.g., JPEG) gives, the values to be interpolated are treated as "Don't cares" and then provided so as to minimize the loss for the measured values. The algorithms presented require no additional memory and entail a reasonable increase in run-time.

Abstract: A technique, referred to as area-based interpolation, performs image interpolation. The system determines a curve by the pixel value at a location by taking the integral of a curve over a small area, where the size of the area is determined by the sampling size of a sampling cell. When the image is resampled with respect to a sampling cell that has a finer spacing, the system integrates the polynomial using a finer integration area. In accordance with the invention, the relation between the reintegrated, resampled high resolution image and the low resolution image is a function of an up-sampler, followed by a linear filter. The coefficients of the filter are independent of the data, but are dependent on the family of curves used. If the system models by, for example, a third degree or fourth degree polynomial everywhere in the image, then that model determines the number of coefficients that are in the filter.