Currently there is a considerable development of small, lightweight, lidar systems, for applications in autonomous cars. The development gives possibilities to equip small UAVs with this type of sensor. Adding an active sensor component, beside the more common passive UAV sensors, can give additional capabilities. This paper gives experimental examples of lidar data and discusses applications and capabilities for the platform and sensor concept including the combination with data from other sensors. The lidar can be used for accurate 3D measurements and has a potential for detection of partly occluded objects. Additionally, positioning of the UAV can be obtained by a combination of lidar data and data from other low-cost sensors (such as inertial measurement units). The capabilities are attainable both for indoor and outdoor shortrange applications.
The architecture and calibration of a hyperspectral imaging sensor based on an exponentially continuously variable narrow-band transmission filter is described. The system design allows for great flexibility in choice of sensors and lenses to be used. Spectral and radiometric calibration using lenses of different focal length and vignetting characteristics is described. The point-spread-function at different wavelengths depends on the lens design and the f-number. The advantage of using a tilt/shift lens is demonstrated. Low f-number lenses show vignetting, which influences both the spectral and radiometric calibration. Retroeffects in the microlenses of the focal plane array are observed but to a large extent will be remedied by future improvements in the optical filter. Noise properties of the sensor system are discussed, and signal-to-noise ratios estimated. From the model, it is possible to obtain parametric performance variations based on the properties of key components. Finally, the sensor performance is indicated by demonstrating a spectral image.
Hyperspectral imaging in the longwave infrared region (LWIR) offers a unique day and night sensor capability currently not available in other spectral ranges. Current proliferation of the technology is however often limited by the size, weight, power and cost (SWaP-C) requirements of the available instruments. This paper presents a low-cost spatial Fourier Transform LWIR hyperspectral imaging camera, based on a corner cube Michelson interferometer and an uncooled microbolometer. In addition to conventional spatial pushbroom scanning, e.g. provided by a moving platform, the current interferometric setup can use temporal scanning of a stationary field-of-view due to a spatially offset stepper motor controlled corner cube retroreflector. The design and calibration and a characterization of the instrument are presented. Applications and future modifications are also discussed.