Employing pixel density to detect a spam image

A network device for selectively managing delivery of messages over a network, comprising:

• a transceiver to send and receive data over the network;
• and
• a processor that is operative to perform actions, including:
• receiving a message, wherein the message includes an image file;
• extracting the image file from the message;
• forwarding the message with the image file towards a destination for display based on at least one physical characteristic of the image file indicating that the image file is unlikely to be image spam, wherein at least one physical characteristic includes at least one of a file type, file size, or file dimension, otherwise:
• performing pixel edge detection within the extracted image that includes at least eliminating weak edges by converting a pixel to black if its threshold chrominance is below a defined threshold;
• determining a normalized pixel density distribution (PDD) for the edge detected image;
• performing a multi-dimensional statistical analysis on the normalized PDD to determine whether the image file is likely to be an image spam file based on a PDD threshold;
• if the analysis 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;
• if the analysis 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 indications from the statistical analysis;
• and
• employing the feedback to modify the PDD threshold.

A system for use in selectively enabling delivery of content over a network, comprising:

• a message server device to perform actions, including:
• receiving a message;
• and
• if the message includes an image file, providing the image file to an image spam detection component;
• and
• a server device having the image spam detection component operating thereon that is configured to perform actions, including:
• extracting the image file from the message;
• forwarding the message with the image file towards a destination for display based on at least one physical characteristic of the image file indicating that the image file is unlikely to be image spam, wherein at least one physical characteristic includes at least one of a file type, file size, or file dimension, otherwise:
• performing pixel edge detection within the extracted image that includes at least eliminating weak edges by converting a pixel to black if its threshold chrominance is below a defined threshold;
• determining a normalized pixel density distribution (PDD) for the edge detected image;
• performing a multi-dimensional statistical analysis on the normalized PDD to determine whether the image file is likely to be an image spam file based on a PDD threshold that is automatically modified based on a number of false-positives;
• if the analysis 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;
• if the analysis 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 indications from the statistical analysis;
• and
• employing the feedback to modify the PDD threshold.