Methods for identifying imaging devices and classifying images acquired by unknown imaging devices
AssigneeForensic Pathways
InventorsLi Chang-Tsun, Richard Leary
Life of this patent
Estimating the term…
Abstract
A method of classifying an image taken by an image capture device, the method comprising the steps of: extracting an initial Sensor Noise Pattern (SNP) for the image; enhancing the initial SNP to create an enhanced SNP by applying a correcting model, wherein the correcting model scales the initial SNP by a factor inversely proportional to the signal intensity of the initial SNP; determining a similarity measure between the enhanced SNP for said image with one or more previously calculated enhanced SNPs for one or more different images; and classifying the image in a group of one or more images with similar or identical SNPs based on the determined similarity measure.
Claims12
A method of identifying an image capture device based on an enhanced Sensor Noise Pattern extracted from an image under investigation, the method comprising the steps of:
- extracting an initial Sensor Noise Pattern (SNP) for the image under investigation;
- enhancing the initial SNP to create an enhanced SNP by applying a correcting model, wherein the correcting model scales the initial SNP by a factor which is an inverse function of the magnitude of the signal intensity of the initial SNP;
- determining a similarity measure between the enhanced SNP for said image with one or more previously calculated enhanced SNPs for one or more image capture devices;
- and
- identify the image capture device with its reference enhanced SNP most similar or identical to enhanced SNP of the image under investigation based on the determined similarity measure.
The method of any preceding claim wherein the similarity measurement is based on a comparative measure of the input and reference images.
A method of identifying a plurality of images as originating from the same image capture device the method comprising:
- classifying the image according to the method of any preceding claim;
- and
- further comprising the step of identifying a classified group of images as originating from the same image capture device.
Apparatus for identifying an image taken by an image capturing device, the apparatus comprising:
- a processor enabled to extract an initial Sensor Noise Pattern (SNP) from the image;
- an enhancer enabled to enhance the initial SNP to create an enhanced SNP by applying a correcting model, wherein the correcting model scales the initial SNP by a factor which is an inverse function of the signal intensity of the initial SNP;
- a similarity measurer to determine the similarity between the enhanced SNP for said image with one or more previously calculated enhanced SNPs for one or more different images;
- and
- an identifier to identify the image capture device with its reference enhanced SNP most similar or identical to the enhanced SNP of the image under investigation based on the determined similarity measure.
Dependencies are inferred from the claim text.