Ungulate Detection and Species Classification from Camera Trap Images Using RetinaNet and Faster R-CNN.

Changes in the ungulate population density in the wild has impacts on both the wildlife and human society. In order to control the ungulate population movement, monitoring systems such as camera trap networks have been implemented in a non-invasive setup. However, such systems produce a large number of images as the output, hence making it very resource consuming to manually detect the animals. In this paper, we present a new dataset of wild ungulates which was collected in Latvia. Moreover, we demonstrate two methods, which use RetinaNet and Faster R-CNN as backbones, respectively, to detect the animals in the images. We discuss the optimization of training and impact of data augmentation on the performance. Finally, we show the result of aforementioned tune networks over the real world data collected in Latvia.

Validation and Comparison of Water Quality Products in Baltic Lakes Using Sentinel-2 MSI and Sentinel-3 OLCI Data.

Inland waters, including lakes, are one of the key points of the carbon cycle. Using remote sensing data in lake monitoring has advantages in both temporal and spatial coverage over traditional in-situ methods that are time consuming and expensive. In this study, we compared two sensors on different Copernicus satellites: Multispectral Instrument (MSI) on Sentinel-2 and Ocean and Land Color Instrument (OLCI) on Sentinel-3 to validate several processors and methods to derive water quality products with best performing atmospheric correction processor applied. For validation we used in-situ data from 49 sampling points across four different lakes, collected during 2018. Level-2 optical water quality products, such as chlorophyll-a and the total suspended matter concentrations, water transparency, and the absorption coefficient of the colored dissolved organic matter were compared against in-situ data. Along with the water quality products, the optical water types were obtained, because in lakes one-method-to-all approach is not working well due to the optical complexity of the inland waters. The dynamics of the optical water types of the two sensors were generally in agreement. In most cases, the band ratio algorithms for both sensors with optical water type guidance gave the best results. The best algorithms to obtain the Level-2 water quality products were different for MSI and OLCI. MSI always outperformed OLCI, with R2 0.84-0.97 for different water quality products. Deriving the water quality parameters with optical water type classification should be the first step in estimating the ecological status of the lakes with remote sensing.

Noninvasive optical diagnostics of enhanced green fluorescent protein expression in skeletal muscle for comparison of electroporation and sonoporation efficiencies.

We highlight the options available for noninvasive optical diagnostics of reporter gene expression in mouse tibialis cranialis muscle. An in vivo multispectral imaging technique combined with fluorescence spectroscopy point measurements has been used for the transcutaneous detection of enhanced green fluorescent protein (EGFP) expression, providing information on location and duration of EGFP expression and allowing quantification of EGFP expression levels. For EGFP coding plasmid (pEGFP-Nuc Vector, 10 µg/50 ml 10 µg/50 ml ) transfection, we used electroporation or ultrasound enhanced microbubble cavitation [sonoporation (SP)]. The transcutaneous EGFP fluorescence in live mice was monitored over a period of one year using the described parameters: area of EGFP positive fibers, integral intensity, and mean intensity of EGFP fluorescence. The most efficient transfection of EGFP coding plasmid was achieved, when one high voltage and four low voltage electric pulses were applied. This protocol resulted in the highest short-term and long-term EGFP expression. Other electric pulse protocols as well as SP resulted in lower fluorescence intensities of EGFP in the transfected area. We conclude that noninvasive multispectral imaging technique combined with fluorescence spectroscopy point measurements is a suitable method to estimate the dynamics and efficiency of reporter gene transfection in vivo.

Noncontact monitoring of vascular lesion phototherapy efficiency by RGB multispectral imaging.

A prototype low-cost RGB imaging system consisting of a commercial RGB CMOS sensor, RGB light-emitting diode ring light illuminator, and a set of polarizers was designed and tested for mapping the skin erythema index, in order to monitor skin recovery after phototherapy of vascular lesions, such as hemangiomas and telangiectasias. The contrast of erythema index (CEI) was proposed as a parameter for quantitative characterization of vascular lesions. Skin recovery was characterized as a decrease of the CEI value relative to the value before the treatment. This approach was clinically validated by examining 31 vascular lesions before and after phototherapy.

Towards noncontact skin melanoma selection by multispectral imaging analysis.

A clinical trial comprising 334 pigmented and vascular lesions has been performed in three Riga clinics by means of multispectral imaging analysis. The imaging system Nuance 2.4 (CRi) and self-developed software for mapping of the main skin chromophores were used. Specific features were observed and analyzed for malignant skin melanomas: notably higher absorbance (especially as the difference of optical density relative to the healthy skin), uneven chromophore distribution over the lesion area, and the possibility to select the "melanoma areas" in the correlation graphs of chromophores. The obtained results indicate clinical potential of this technology for noncontact selection of melanoma from other pigmented and vascular skin lesions.

2-D mapping of skin chromophores in the spectral range 500 - 700 nm.

The multi-spectral imaging technique has been used for distant mapping of in-vivo skin chromophores by analyzing spectral data at each reflected image pixel and constructing 2-D maps of the relative concentrations of oxy-/deoxy-haemoglobin and melanin. Instead of using a broad visible-NIR spectral range, this study focuses on narrowed spectral band 500-700 nm, speeding-up the signal processing procedure. Regression analysis confirmed that superposition of three Gaussians is optimal analytic approximation for the oxy-haemoglobin absorption tabular spectrum in this spectral band, while superposition of two Gaussians fits well for deoxy-haemoglobin absorption and exponential function - for melanin absorption. The proposed approach was clinically tested for three types of in-vivo skin provocations: ultraviolet irradiance, chemical reaction with vinegar essence and finger arterial occlusion. Spectral range 500-700 nm provided better sensitivity to oxy-haemoglobin changes and higher response stability to melanin than two reduced ranges 500-600 nm and 530-620 nm.