Protecting personal privacy in a video monitoring system
An image acquisition device compresses a media signal representative of a scene based on a sensing matrix that is a determined by a sensing matrix template and a set of template parameters. The image acquisition device provides the compressed media signal to a receiver and selectively provides a specification of a subset of the set of template parameters to the receiver. The receiver extracts one or more scene descriptors representative of one or more portions of the scene from the compressed media signal using the sensing matrix template without knowledge of the template parameters that are not included in the subset. The template parameters that are not included in the subset are not received by the receiver.
1. A method comprising:
compressing, at an image acquisition device, a media signal representative of a scene based on a sensing matrix that is a determined by a sensing matrix template and a set of template parameters;
providing, from the image acquisition device, the compressed media signal to a receiver; and
selectively providing a specification of a subset of the set of template parameters to the receiver so that the media signal cannot be reconstructed from the provided compressed media signal using the provided specification of the subset of the set of template parameters.
2. The method of claim 1 , wherein the media signal is a video signal.
3. The method of claim 1 , wherein the sensing matrix template comprises at least one matrix template, and wherein said at least one matrix template is determined by parameters from the set of template parameters.
4. The method of claim 3 , wherein the set of template parameters comprises at least one random number generator seed, and wherein selectively providing the specification comprises selectively providing a subset of the set of template parameters that does not include the random number generator seed.
5. The method of claim 3 , wherein:
the at least one matrix template comprises a first random matrix and a second matrix;
the set of template parameters comprises a random number generator seed;
the first random matrix is determined by a sequence of parameters generated by a random number generator using the random number generator seed; and
the sensing matrix is the product of the first random matrix and the second matrix.
6. The method of claim 5 , further comprising:
determining the first random matrix based on at least one of a random circulant transform, a locally randomized discrete Fourier transform, or a random convolution transform.
7. The method of claim 1 , further comprising:
providing a first random number seed in addition to the subset of the set of template parameters in response to detection of an anomaly that requires reconstruction of the compressed media signal.
8. The method of claim 1 , wherein a specification of the set of template parameters is provided in response to detecting an anomaly that indicates that the receiver is required to reconstruct the media signal from the compressed media signal.
9. A method comprising:
compressing, at an image acquisition device, a media signal representative of a scene based on a sensing matrix that is a determined by a sensing matrix template and a set of template parameters that includes a random number seed;
providing, from the image acquisition device, the compressed media signal to a receiver; and
selectively providing a specification of a subset of the set of template parameters to the receiver, wherein the subset does not include the random number seed so that the media signal cannot be reconstructed from the provided compressed media signal using the provided specification of the subset of the set of template parameters.
10. The method of claim 9 , wherein the media signal is a video signal.
11. The method of claim 9 , wherein the sensing matrix template comprises at least one matrix template, and wherein said at least one matrix template is determined by parameters from the set of template parameters.
12. The method of claim 11 , wherein:
the at least one matrix template comprises a first random matrix and a second matrix;
the set of template parameters comprises a random number generator seed;
the first random matrix is determined by a sequence of parameters generated by a random number generator using the random number generator seed; and
the sensing matrix is the product of the first random matrix and the second matrix.
13. The method of claim 12 , further comprising:
determining the first random matrix based on at least one of a random circulant transform, a locally randomized discrete Fourier transform, or a random convolution transform.
14. The method of claim 13 , further comprising:
providing the random number generator seed to the receiver in response to detection of an anomaly that requires reconstruction of the compressed media signal.