Abstract: The method comprises acquiring a bidimensional image formed by a plurality of dots, characterized by a brightness value; dividing the bidimensional image into a plurality of image regions, each formed by a respective first number of dots; for each of the image regions, determining a first quantity correlated to the brightness variation intensity of each dot with respect to adjacent dots; for each image region, determining at least one second quantity correlated to the brightness variation direction of each dot with respect to adjacent dots; and determining any presence and type of a code in each of the image regions, on the basis of the determined quantities. These quantities typically comprise the contrast level of the image region, obtained by adding the gradient variation intensity of all contrast dots of the image region and directionality of the image region, obtained by calculating the gradient variation direction for all dots and searching for the prevalent direction or directions.

Abstract: A method of compensating the edge positions of a signal generated by scanning elements of a bar code, the method including the steps of lighting the code and determining the light diffused by the code to generate in response a signal having a substantially alternating waveform defined by a sequence of high-amplitude portions separated by and joined to low-amplitude portions by steeply sloping edges of the waveform. A number of local minimum and maximum points of the waveform are determined to determine coordinates defining approximate edge positions. The coordinates are then corrected to generate modified coordinates, each relative to a corrected position of the edge compensating for any shift in the edge induced by blurring of the signal.

Abstract: A method of estimating the mid-points of elements of a bar code, wherein the code is illuminated, and the light diffused by the code is picked up to generate in response a signal having a substantially alternating waveform profile defined by high-amplitude zones alternating with low-amplitude zones; each high-amplitude zone corresponding to a space of the code, and each low-amplitude zone corresponding to a bar of the code. The signal is then quantized to obtain a discretized waveform having a number of local maximum and minimum points, and an observation window of a given width is defined by which to observe the waveform. The observation window is positioned on the maximum and minimum points of the discretized waveform to eliminate redundant maximum and minimum points within the observation window.