Abstract: Systems and methods for illuminating a platen are provided. A hybrid illumination system uses both diffusion and collimation to efficiently provide a flat, uniform illumination at a platen. One or more diffusers are disposed between the illumination source array and a collimating lens. An illumination system is provided which uses diffused light to illuminate a platen in a print scanner. The illumination system has an illumination source array and a light wedge. The light wedge reflects light internally which makes the illumination even more diffuse. An illumination source array has a plurality of sources that emit blue/green light. In one preferred example, the blue/green light is equal to or approximately equal to 510 nm. Sources are divided into at least a center region and a perimeter region. The density of sources provided in the perimeter region is greater than in the center region to correct for natural light falloff in the illumination system.

Abstract: A system and method for obtaining a biometric image such as a ten-print fingerprint impression is provided. The system and method can include a ten-print scanner having a platen and a finger guide coupled to the platen. The finger guide can be used to guide positioning a finger slap of four fingers at a time onto the platen. The ten-print scanner can also include at least four indicators that indicate an acceptable scan condition of each finger of a finger slap in response to a detected finger slap image.

Abstract: Devices and methods for applying heat to a platen of a biometric image capturing device are described that remove and prevent the formation of excess moisture on the platen. These devices and methods prevent undesirable interruptions of total internal reflection of a prism that result in biometric images having a halo effect. In embodiments of the invention, an electrically conductive transparent material is used to apply heat to the platen. In other embodiments, resistive heating elements attached to non-optical areas of the platen (e.g., the ends) are used to apply heat to the platen. Heater assemblies according to the invention can be used to heat an area where a biometric object is placed, or an area adjacent to where the biometric object is placed, to remove and prevent the formation of excess moisture on the platen.

Abstract: The present invention relates to systems and methods for enhancement of biometric object image capturing. These systems and methods prevent undesirable interruptions of total internal reflection of a prism that result in improper biometric images. In embodiments of the invention, a thermal assembly comprising a plurality of thermal elements is placed adjacent to the image capturing device. The thermal elements upon supply of a current are capable of either heating or cooling the image capturing device or a platen of the image capturing device. If cooling of the biometric object receiving surface is required, the thermal elements can be controlled to decrease temperature of an area where a biometric object is placed, or an area adjacent to where the biometric object is placed.

Abstract: A DC to DC converter includes a first transistor having a first power terminal connected to one side of a DC power supply and a second power terminal connected to one end of an inductor. A second transistor has a first power terminal connected to the other end of the inductor and a second power terminal connected to the other side of the DC power supply. A pair of capacitors is connected in series and defined therebetween a node which is connected to a ground potential. A third transistor has a first power terminal connected to the one end of the inductor and a second power terminal connected to one end of the pair of capacitors. A fourth transistor has a first power terminal connected to the other end of the pair of capacitors and a second power terminal connected to the other end of the inductor. Each transistor includes a diode connected between the first power terminal and the second power terminal thereof. Each diode is oriented to conduct current in a direction opposite its corresponding transistor.

Abstract: A streaming current detector includes an optical shutter rotated by the shaft of the motor which reciprocates a piston between electrodes in a bore containing sample fluid. An electronic synchronous detector is controlled by the output of a light detector whose source is interrupted by the optical shutter. The alternating current signals from the electrodes are connected to an operational amplifier having its inverting input connected to its output solely by a capacitor so that the output voltage is proportional to the charge of the fluid.