摘要:
A method for detecting an amount of rotation or magnification in a modified image, includes the steps of: embedding a marker image having a pair of identical features separated by a distance d and oriented at an angle .alpha. in an original image to produce a marked image, the marked image having been rotated and/or magnified to produce the modified image; performing an autocorrelation on the modified image to produce a pair of autocorrelation peaks corresponding to the location of the features of the marker image in the modified image; and comparing the separation d' and orientation .alpha.' of the autocorrelation peaks with the separation d and orientation .alpha. of the features in the marker image to determine the amount of rotation and magnification in the modified image.
摘要:
A method for calculating a skew angle of an original image, executed at least in part on a computer system stores image data for the original image in an electronic memory, then forms an energy-normalized image according to the relative contrast amplitude of image features over each of a plurality of local image regions within the stored image data. A partitioned image is formed by partitioning the energy-normalized image into a number of sub-regions. A summed region is formed as a combination of image pixel data from the sub-regions. A Fourier magnitude spectrum is obtained by performing a Fourier transform on the summed region. The skew angle is calculated according to the peak value of a radial line integration function that is formed by integrating the Fourier magnitude spectrum along each of a plurality of lines of constant radial angles. An output signal indicates the calculated skew angle.
摘要:
A method for assessing the image quality of image data acquires image data, segments the image data into at least one spatial region, obtains a plurality of image quality measures for the at least one spatial region, and forms at least one quality vector that has two or more quality measures for the at least one spatial region. The at least one quality vector is classified into one of a plurality of predefined quality classes.
摘要:
A method for calculating a skew angle of an original image, executed at least in part on a computer system stores image data for the original image in an electronic memory, then forms an energy-normalized image according to the relative contrast amplitude of image features over each of a plurality of local image regions within the stored image data. A partitioned image is formed by partitioning the energy-normalized image into a number of sub-regions. A summed region is formed as a combination of image pixel data from the sub-regions. A Fourier magnitude spectrum is obtained by performing a Fourier transform on the summed region. The skew angle is calculated according to the peak value of a radial line integration function that is formed by integrating the Fourier magnitude spectrum along each of a plurality of lines of constant radial angles. An output signal indicates the calculated skew angle.
摘要:
A method of extracting a voice command produced in an enclosed or partially enclosed environment, includes providing an impulse response signal of the enclosed or partially enclosed environment; recording the voice command and ambient sounds; and using the impulse response signal to extract the recorded voice command.
摘要:
A method and system is disclosed for printing an authenticatable image having an embedded image into a receiver having a discernible physical characteristic, such that the printed image can be used to authenticate the receiver which includes scanning the receiver to produce information related to the discernible physical characteristic of the receiver, and providing a carrier which includes information related to the scanned receiver discernible physical characteristic. The method also includes combining the carrier with an input image to form the authenticatable image having the embedded image, and printing the authenticatable image having the embedded image onto the receiver.
摘要:
An improved method and computer program product for detecting an amount of rotation or magnification in a modified image, of the type including the steps of: a) embedding a marker image having a pair of identical features separated by a distance d and oriented at an angle &agr; in an original image to produce a marked image, the marked image having been rotated and/or magnified to produce the modified image; b) performing an autocorrelation on the modified image to produce a pair of autocorrelation peaks corresponding to the location of the features of the marker image in the modified image; and c) comparing the separation d and orientation &agr; of the autocorrelation peaks with the separation d and orientation &agr; of the features in the marker image to determine the amount of rotation and magnification in the modified image, wherein the improvement comprises the step of: d) preprocessing the modified image to have a constant standard deviation over all local regions in the image.
摘要:
A method and computer program for extracting an embedded message from a digital image, the embedded message being formed by convolution with a carrier, employs a message template indicating the relative locations of data in the embedded message, the relative locations of the data being such that the autocorrelation of the message template is strongly peaked. An arbitrary region of the digital image is correlated with the carrier to extract a cyclically shifted message from the digital image. The absolute value of the cyclically shifted message is taken to form a positive valued cyclically shifted message. The positive valued cyclically shifted message is correlated with the message template to form a shifted offset image having a peak amplitude representing the location of the message boundary. The location of the message boundary is employed to extract the hidden message.
摘要:
In a method of embedding a hidden message in digital data, employing plurality of orthogonal random arrays of numbers as carriers for the bits of the hidden message, the random arrays are generated by applying a plurality of unique cyclical shifts to a single random array. In a preferred embodiment, the method is applied to digital image data and the cyclical shifts are defined as locations in a shift template, wherein the shift template has a highly peaked autocorrelation. The shift template is employed to recover the hidden message from the image without the need for calibration signals to indicate the boundaries of the hidden message.
摘要:
The method and system embeds digital meta-data into an original image in such a way that the meta-data can be completely removed at a later time to allow loss less recovery of the original image. The loss less recovery of the original image allows for a digital signature of the image to be embedded in the image itself and later recovered and used to verify the authenticity of a received image.