METHODS AND SYSTEMS FOR DETECTING A SECURITY MARK IN A COLORED MEDIA DOCUMENT
The present disclosure discloses methods and systems for detecting a security mark embedded in a colored media document. The method includes extracting a region of the document, wherein the region corresponds to a location of the document. Thereafter, color values associated with a color channel of the extracted region are analyzed. Based on the analysis, at least one foreground threshold value and at least one adjacent foreground threshold value are calculated. Here, the foreground threshold value and the adjacent foreground threshold value depend at least on a color of a media of the colored media document. Thereafter, the extracted region is processed using the at least one foreground threshold value to generate a foreground image. Further, the extracted portion is processed using the at least one adjacent foreground threshold value to generate an adjacent foreground image. Once generated, the foreground image and the adjacent foreground image are analyzed, and based on the analysis the security mark embedded in the colored media document is detected.
1 . A method for detecting a security mark embedded in a colored media document, the method comprising:
extracting a region of the colored media document, wherein the region comprises a location of the colored media document;
analyzing color values associated with a color channel of the extracted region;
determining, based on the analysis, at least one foreground threshold value and at least one adjacent foreground threshold value, wherein the foreground threshold value and the adjacent foreground threshold value depend at least on a color of a media of the colored media document;
processing, using the at least one foreground threshold value, the extracted region to generate a foreground image;
processing, using the at least one adjacent foreground threshold value, the extracted region to generate an adjacent foreground image; and
detecting, based on analysis of the foreground image and the adjacent foreground image, the security mark embedded in the colored media document.
2 . The method of claim 1 , wherein the color values comprise:
a CIELAB color space, and the color channel is at least one of L-channel, a-channel, or b-channel.
3 . The method of claim 1 , wherein analyzing the color values comprises analyzing a histogram of the color values associated with the color channel to identify a mean of the histogram, one or more peaks of the histogram and one or more valleys of the histogram.
4 . The method of claim 3 , wherein the at least one foreground threshold value is identified using the one or more valleys of the histogram or the mean of the histogram.
5 . The method of claim 3 , wherein the at least one adjacent foreground threshold value is identified using the one or more valleys of the histogram and the one or more peaks of the histogram.
6 . The method of claim 3 , wherein the color value corresponding to a first valley of the one or more valleys is identified as a lower threshold value for a foreground portion.
7 . The method of claim 6 , wherein the color value corresponding to the mean of the histogram is identified as an upper threshold value for the foreground portion.
8 . The method of claim 6 , wherein the color value corresponding to a second valley of the one or more valleys located in a direction of a lower color value than a highest peak of the one or more peaks is identified as a lower threshold value for an adjacent foreground portion adjacent to the foreground portion.
9 . The method of claim 8 , wherein the color value corresponding to a third valley located in the direction of a higher color value than a highest peak of the one or more peaks is identified as an upper threshold value for the adjacent foreground portion.
10 . The method of claim 1 , wherein processing, using the at least one foreground threshold value, comprises:
comparing the color values associated with the color channel of the extracted region with the at least one foreground threshold value to generate the foreground image.
11 . The method of claim 6 , wherein processing, using the at least one adjacent foreground threshold value comprises:
identifying, using the foreground image, one or more portions adjacent to one or more of the foreground portions in the extracted region; and
comparing the color values associated with the color channel of the identified one or more portions adjacent to the one or more foreground portions in the extracted region with the adjacent foreground threshold value to generate the adjacent foreground image.
12 . The method of claim 1 , further comprising:
combining the foreground image and the adjacent foreground image to create a created image;
extracting the security mark from the created image; and
verifying an authenticity of the colored media document by matching the extracted security mark with one or more pre-selected security marks.
13 . A multi-function device for detecting a security mark embedded in a colored media document, the multi-function device executing instructions to perform operations comprising:
extracting a region of the colored media document, wherein the region comprises a location of the colored media document;
analyzing color values associated with a color channel of the extracted region;
determining, based on the analysis, at least one foreground threshold value and at least one adjacent foreground threshold value, wherein the foreground threshold value and the adjacent foreground threshold value depend at least on a color of a media of the colored media document;
processing, using the at least one foreground threshold value, the extracted region to generate a foreground image;
processing, using the at least one adjacent foreground threshold value, the extracted region to generate an adjacent foreground image; and
detecting, based on analysis of the foreground image and the adjacent foreground image, the security mark embedded in the colored media document.
14 . The multi-function device of claim 13 , where the operations further comprise:
selecting the color channel from a CIELAB color space including L-channel, a-channel, and b-channel; and
obtaining the color values associated with the selected color channel.
15 . The multi-function device of claim 13 , wherein analyzing the color values comprises:
identifying a mean of a histogram of the color values associated with the color channel, one or more peaks of the histogram and one or more valleys of the histogram.
16 . The multi-function device of claim 15 , wherein the at least one foreground threshold value is identified using the one or more valleys of the histogram or the mean of the histogram.
17 . The multi-function device of claim 15 , wherein the at least one adjacent foreground threshold value is identified using the one or more valleys of the histogram and the peaks of the histogram.
18 . The multi-function device of claim 13 , wherein processing, using the at least one foreground threshold value, comprises:
comparing the color values associated with the color channel of the extracted region with the at least one foreground threshold value to generate the foreground image.
19 . The multi-function device of claim 13 , wherein processing, using the at least one adjacent foreground threshold value, comprises:
identifying, using the foreground image, one or more portions adjacent to one or more foreground portions in the extracted region; and
comparing the color values associated with the color channel of the identified one or more portions adjacent to the one or more foreground portions in the extracted region with the adjacent foreground threshold value to generate the adjacent foreground image.
20 . The multi-function device of claim 13 , wherein the operations further comprise:
combining the foreground image and the adjacent foreground image to create a created image;
extracting the security mark from the created image; and
verifying an authenticity of the colored media document by matching the extracted security mark with one or more pre-selected security marks.