Employing pixel density to detect a spam image
First Claim
1. A method for use in managing delivery of content over a network, comprising:
- receiving a message, wherein the message includes an image file;
extracting the image file from the message;
converting the image file to a grayscale image;
performing pixel edge detection within the grayscale image that includes at least eliminating weak edges by converting a pixel to black if its threshold chrominance is below a defined threshold, and eliminating weak edges by converting a contrast of a pixel within a determined weak edge to a higher contrast;
determining a pixel density distribution (PDD) for the edge detected image;
if the PDD statistically indicates that the image file is an image spam file, performing an action to inhibit at least the image file from being forwarded to a destination associated with the message; and
if the PDD statistically indicates that the image file is not image spam, forwarding the message with the image file towards a destination such that the image file is viewable by a recipient at a display;
collecting feedback based, in part, on a number of false-positives for the statistical indications; and
employing the feedback to modify a PDD statistical threshold useable in indicating if the image file is an image spam file.
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Accused Products
Abstract
A network device and method are directed towards detecting and blocking image spam within a message by performing statistical analysis on differences in edge pixel distribution patterns. An image spam detection component receives a message with an image attachment. Physical characteristics of the image are examined to determine whether the image is a candidate for further analysis. If so, then the image may be converted to a grayscale image, and then performing edge detection, followed by the elimination of non-maxima and thresholding of weak edges. Edge pixels and then employed to determine a normalized pixel density distribution (PDD). Various statistical analyses are applied to the resulting normalized PDD to determine a likelihood that the image is spam. A signature based exemption may be applied to images improperly identified as spam, based on trusted user feedback.
62 Citations
19 Claims
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1. A method for use in managing delivery of content over a network, comprising:
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receiving a message, wherein the message includes an image file;
extracting the image file from the message;converting the image file to a grayscale image; performing pixel edge detection within the grayscale image that includes at least eliminating weak edges by converting a pixel to black if its threshold chrominance is below a defined threshold, and eliminating weak edges by converting a contrast of a pixel within a determined weak edge to a higher contrast; determining a pixel density distribution (PDD) for the edge detected image;
if the PDD statistically indicates that the image file is an image spam file, performing an action to inhibit at least the image file from being forwarded to a destination associated with the message; andif the PDD statistically indicates that the image file is not image spam, forwarding the message with the image file towards a destination such that the image file is viewable by a recipient at a display; collecting feedback based, in part, on a number of false-positives for the statistical indications; and employing the feedback to modify a PDD statistical threshold useable in indicating if the image file is an image spam file. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A network device for selectively managing delivery of messages over a network, comprising:
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a transceiver to send and receive data over the network; and a processor that is operative to perform actions, including; receiving an image file associated with a message; determining at least one physical characteristic of the image file; and
if the physical characteristic indicates that statistically, the image file is unlikely to be associated with image spam, enabling the image file and message to be forwarded to a destination, otherwise performing the following actions, comprising;converting the image file to a grayscale image; performing pixel edge detection within the grayscale image and eliminating weak edges by converting a pixel to black if its threshold chrominance is below a defined threshold, and eliminating weak edges by converting a contrast of a pixel within a determined weak edge to a higher contrast; determining a pixel density distribution (PDD) for the edge detected image; if the PDD statistically indicates that the image file is an image spam file, performing an action to inhibit at least the image file from being forwarded to a destination associated with the message; and if the PDD statistically indicates that the image file is not image spam, forwarding the message with the image file towards the destination such that the image file is viewable by a recipient at a display; collecting feedback based, in part, on a number of false-positives for the statistical indications; and employing the feedback to modify a PDD statistical threshold useable in indicating if the image file is an image spam file. - View Dependent Claims (8, 9, 10, 11, 12, 13)
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14. A system for use in selectively enabling delivery of content over a network, comprising:
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a message server that is configured and arranged to perform actions, including;
receiving a message; andif the message includes an image file, providing the image file to an image spam detection component; and the image spam detection component being configured to perform actions, including; converting the image file to a grayscale image; performing pixel edge detection within the grayscale image and eliminating weak edges by converting a pixel to black if its threshold chrominance is below a defined threshold, and eliminating weak edges by converting a contrast of a pixel within a determined weak edge to a higher contrast; determining a pixel density distribution (PDD) for the edge detected image; if the PDD statistically indicates that the image file is an image spam file, providing an alert to the message server such that the image file is prevented from being forwarded to a destination associated with the message; and if the PDD statistically indicates that the image file is not image spam, providing an indicator to the message server such that the image file is forwarded towards the destination such that the image file is viewable by at the destination; collecting feedback based, in part, on a number of false-positives for the statistical indications; and employing the feedback to modify a PDD statistical threshold useable in indicating if the image file is an image spam file. - View Dependent Claims (15, 16, 17, 18, 19)
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Specification