Night vision

About: Night vision is a research topic. Over the lifetime, 6004 publications have been published within this topic receiving 67372 citations.

Characterization of small metallic objects and nonmetallic antipersonnel mines

Abstract: A metallic mine detector is one of the most effective pieces of equipment for detection of mines. Their main drawback is their extremely rate of up to 100 percent, but it can also produce a high false alarm rate in many environments. The high false alarm rate reduces the usefulness of the metal detector in the field. In order to keep a high detection rate with fewer false alarms, object/mine characterization or identification must be used. Several techniques have been implemented to reduce the false alarm rate of metal detectors. They are size discrimination, target imaging, and target signatures such as dipole moment characterization. These techniques are applied for large metallic objects/mines. P.V. Czipott and D.A. Waldron each used separate techniques to characterize smaller metallic objects and some anti-personnel mines, in work supported by US Army CECOM, Night Vision and Electronic Sensors Directorate. Dr. Czipott characterized objects/mines by measuring the frequency dependence of magnetic fields caused by electric currents induced in the target. The frequency responses were measured by using a fixture incorporating a solenoid excitation coil, a receiving coil wound as a gradiometer, and a HP 4195A network/spectrum analyzer. Ms. Waldron characterized small objects with different conductivities and orientations by measuring their phase differences using a search head with one transmitter and four receiver coils and a phase-lock analyzer. We believe that target discrimination and identification are the keys to reduce false alarm rates of metallic mine detectors. Thus, we continue to analyze and characterize small metallic targets/mines using a variety of methods.

Concealed weapon identification using terahertz imaging sensors

Abstract: Terahertz imaging sensors are being considered for providing a concealed weapon identification capability for military and security applications. In this paper the difficulty of this task is assessed in a systematic way. Using imaging systems operating at 640 GHz, high resolution imagery of possible concealed weapons has been collected. Information in this imagery is removed in a controlled and systematic way and then used in a human observer perception experiment. From the perception data, a calibration factor describing the overall difficulty of this task was derived. This calibration factor is used with a general model of human observer performance developed at the US Army Night Vision and Electronic Sensors Directorate to predict the task performance of observers using terahertz imaging sensors. Example performance calculations for a representative imaging sensor are shown.

Transgenic mice expressing Cre-recombinase specifically in retinal rod bipolar neurons.

Abstract: PURPOSE. To establish a transgenic mouse line that expresses Cre-recombinase in retinal rod bipolar cells for the generation of rod bipolar cell-specific knockout mutants. METHODS. The IRES-Cre-cDNA fragment was inserted into a 173-kb bacterial artificial chromosome (BAC) carrying the intact Pcp2 gene, by using red-mediated recombineering. Transgenic mice were generated with the modified BAC and identified. The Cre-transgenic mice were crossed with ROSA26 and Z/EG reporter mice to detect Cre-recombinase activity. RESULTS. X-gal staining showed that strong Cre-recombinase activities were present in retinal inner nuclear layers and cerebellar Purkinje cells. Double staining with an anti-GFP antibody and an anti-PKCα antibody (specific for retinal rod bipolar cells) revealed that Cre-recombinase activity localized exclusively to the rod bipolar cells in the retina. CONCLUSIONS. A mouse BAC-Pcp2-IRES-Cre transgenic line that expresses Cre-recombinase in retinal rod bipolar neurons has been established. Because mutations in some ubiquitously expressed genes may result in retinal degenerative diseases, the mouse strain BAC-Pcp2-IRES-Cre will be a useful new tool for investigating the effects of retinal rod bipolar cell-specific gene inactivation.