Mosquitos, sometimes carrying deadly diseases such as malaria, zika, and dengue fever, cause much concern. To control mosquitos, it is important to effectively monitor their presence and behavioral trends. We have constructed two optical sensing systems for insects based on light attenuation and light backscattering, respectively. The systems, which were tested with the potentially dangerous Aedes albopictus and Culex pipiens, were able to extract the wing-beat frequency, when they passed impinging light, derived from light-emitting diodes. We could achieve distinction between the sexes of A. albopictus and C. pipiens based on the wing-beat frequency. Finally, we propose a statistical method suitable for the system to improve the accuracy of counting.

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Insects constitute a very important part of the global ecosystem and include pollinators, disease vectors, and agricultural pests, all with pivotal influence on society. Monitoring and control of such insects has high priority, and automatic systems are highly desirable. While capture and analysis by biologists constitute the gold standard in insect identification, optical and laser techniques have the potential for high-speed detection and automatic identification based on shape, spectroscopic properties such as reflectance and fluorescence, as well as wing-beat frequency analysis. The present paper discusses these approaches, and in particular presents a novel method for automatic identification of mosquitos based on image analysis, as the insects enter a trap based on a combination of chemical and suction attraction. Details of the analysis procedure are presented, and selectivity is discussed. An accuracy of 93% is achieved by our proposed method from a data set containing 122 insect images (mosquitoes and bees). As a powerful and cost-effective method, we finally propose the combination of imaging and wing-beat frequency analysis in an integrated instrument.

Numerous natural materials are porous, contain free gas and are scattering light strongly. Scattering brings about a strong trapping of light and an associated prolonged transit time for photons through a medium. In contrast to the matrix materials, gas enclosures require very narrowband laser radiation for probing. We have in the present study used the gas in scattering media absorption spectroscopy method to study free oxygen in thin (cm) samples utilizing a tunable diode laser, while a pulsed dye laser was employed in corresponding measurements on larger samples, up to the meter scale. Time‐resolved spectroscopy was in both cases used to assess the temporal distribution of the detected photons, mapping the path lengths through the media, which ranged between few centimeters up to 100 m. This study explores the feasibility to extend recent successful monitoring of gases in neonatal infant lungs to the case of larger children or even adults, which could have very important applications, for example, in ventilator setting optimization for severely ill patients, suffering, for example, from SARS‐CoV‐2. The conclusion of our work is that this goal most realistically can be reached by applying intratracheal laser light illumination at the 1 W power level, employing a tapered amplifier, injected with a distributed feedback diode‐laser oscillator output and combined with wavelength‐modulation spectroscopy.

We describe a simple approach to enhance vision, which is impaired by close range obscuring and/or scattering structures. Such structures may be found on a dirty windscreen of a car, or by tree branches blocking the vision of objects behind. The main idea is to spatially modulate the obscuration, either by periodically moving the detector/eye or by letting the obscuration modulate itself, such as branches swinging in the wind. The approach has similarities to electronic lock-in techniques, where the feature of interest is modulated to enable it to be isolated from the strong perturbing background, but now, we modulate the background instead to isolate the static feature of interest. Thus, the approach can be denoted as “inverse lock-in-like spatial modulation”. We also apply a new digital imaging processing technique based on a combination of the Interframe Difference and Gaussian Mixture models for digital separation between the objects of interest and the background, and make connections to the Gestalt vision psychology field.