Patent ID: 7609846

Claim:
A method executable by a computer for identifying a digital acquisition device that captures an image using red, green, and blue channels, the method comprising the steps of: obtaining at least a makernote tag data containing a first non-public whitepoint calibration data of a suspected digital acquisition device with the computer; locating a makernote tag data in an image file to be matched with the computer; searching for a second non-public whitepoint calibration data within the makernote tag data located in the image file to be matched with the computer; comparing the first non-public whitepoint calibration data with the second non-public whitepoint calibration data with the computer; and identifying the suspected digital acquisition device as a source of the test image file if the first and second non-public whitepoint calibration data match with the computer, wherein each of the first and second non-public whitepoint calibration data contains a calibration value of the green channel, a calibration value of the red channel, and a calibration value of the blue channel, wherein the searching step includes: detecting a pattern of the green channel calibration value, the red channel calibration value, and the blue channel calibration value contained in the image file to be matched; and first detecting the calibration value of the most transmissive channel among the green, red, and blue channels, and then expanding around a location of the detected most transmissive channel to detect the calibration values of other channels among the green, read, and blue channels.