1. A method for calibrating a scanning device, the method comprising: analyzing a dark scan image of a calibration strip to obtain at least one data point from each of one or more regions of the dark scan image; computing calibration values for each of the one or more regions based on the at least one data point for calibrating the scanning device, wherein the calibration values include mean and standard deviation of the data points for each of the one or more regions; comparing the calibration values with reference calibration values corresponding to each of the one or more regions, wherein the calibration values are current calibration values; and determining if the current calibration values are erroneous based on the comparing.