摘要:
A quantum well infrared photodetector (QWIP) focal plane array having structures, each structure having stacked layers of quantum wells and a reflective grating to provide polarization sensitivity. The reflective grating is etched to provide electrical contacts for individual pixels. The reflective gratings comprise grooves, where the grooves for a particular structure run in a particular direction to provide polarization sensitivity. Each structure may comprise groups of quantum well layers, each group sensitive to a particular frequency band. By shorting out unwanted quantum well layers, and by forming the reflective gratings to come into contact with the quantum well layers having a particular frequency band sensitivity, the pixels in the QWIP focal plane array may provide frequency and polarization information.
摘要:
Methods and apparatus, including computer program products, for threat detection based on radiation contrast. In general, an image from a device having a sensitivity to infrared radiation having a wavelength between three and fifteen micrometers may be received, images features from the image may be extracted, a classification may be generated of the image features from multiple classifications where the classifications include threats, and data characterizing the classification of the image features may be displayed. The device may operate at a standoff distance of five to one hundred meters. Displaying data characterizing the classification of the image features may include displaying an identification of a person carrying a threat.