Active and passive short-wave infrared and near-infrared imaging for horizontal and slant paths close to ground

Abstract

This paper investigates active and passive short-wave infrared (SWIR) imaging for slant paths close to ground. The main sensor, a gated SWIR camera, was collecting both passive and active images along a 2 km long path over an airfield and also from our rooftop laboratory looking over open fields. For some investigations we also used a gated system working in the near-infrared region and thermal as well as color CCD cameras. The sensor was elevated by a lift in steps from 1.6-13.5 m or placed in a rooftop laboratory 13 m above ground. Targets were resolution charts and man targets. The turbulence was measured along the path with anemometers and scintillometers. The image performance was evaluated by measurement of the image blur and also by performing observer perception tests. The results reveal a strong dependence on the sensor height especially during daytime.

Active hyperspectral imaging with a supercontinuum laser source in the dark

“…Under the conditions like the shadow, the traditional HSI system has difficulty to be effective since the illumination is insufficient. [3,4] What is more, in some extreme conditions where the sun light could not reach, such as in the dark, caves, or deep waters, [5] hyperspectral detection of objects is not possible by using the traditional way.…”

Using Passive and Active Multispectral Sensors on the Correlation With the Phenological Indices of Cotton

“…According to Steinvall et al (2013), passive sensor, such as multispectral cameras, measures reflected energy fromthe target that was emitted from the sun. Multispectral active sensors have its own source of light and its sensor measures reflected energy from the crop canopy.…”

Laser gated viewing at ISL for vision through smoke, active polarimetry, and 3D imaging in NIR and SWIR wavelength bands

“…This method is a promising optronic sensor technology, which is complementary to recent night vision technologies like thermal imaging and intensified low light-level image sensors [4][5][6][7]. Owing to enormous improvements in the development of compact and highly efficient laser sources and in the development of modern sensor technologies, the maturity of laser gated viewing systems rose during the past decades, and for instance, commercial systems are available from Obzerv [8], Intevac [9], Selex [10], and Elbit [11].…”