Video signature comparator and method

Apparatus by which a visual determination can be made as to the authenticity of a sample writing relative to a known, authentic writing depending upon the density/pressure variations in the strokes of each writing, said apparatus comprising:

• means for generating respective input signals which are representative of each of the known and sample writings;
• means for detecting the brightness of said video input signals;
• means for electronically forcing to white any portions of the video input signals which are detected to be lighter than a particular brightness;
• and
• means for displaying the video signals so that only the portions thereof which are detected to be darker than the particular brightness, corresponding to the strokes of each writing to which the greatest pressure was applied by its maker, are visible so that said visible portions can be compared to one another.

A signature comparator for displaying at a video display a known signature and a sample signature so that the sample signature can be compared for authenticity to the known signature, said signature comparator comprising:

• means for providing viedo input signals which are representative of the known and sample signatures;
• reference white level signal generating means;
• means for detecting the brightness of the input signals;
• means to adjust the gain and contrast of the video input signals to enhance the density/pressure variations thereof;
• and
• means to provide to the video display either a white level signal from said reference signal generating means whenever the brightness detected by said brightness detecting means is lighter than a particular brightness of a video enhanced signal from said gain and contrast adjusting means whenever the brightness detected by said brightness detecting means is darker than the particular brightness.