Perspectives in visual imaging for marine biology and ecology: from acquisition to understanding

Durden J, Schoening T, Althaus F, et al. Perspectives in Visual Imaging for Marine Biology and Ecology: From Acquisition to Understanding. In: Hughes RN, Hughes DJ, Smith IP, Dale AC, eds. Oceanography and Marine Biology: An Annual Review. 54. Boca Raton: CRC Press; 2016: 1-72

Combining Odometry and Visual Loop-Closure Detection for Consistent Topo-Metrical Mapping

Abstract—We address the problem of simultaneous localization and mapping (SLAM) by combining visual loop-closure detection with metrical information given by a robot odometry. The proposed algorithm extends a purely appearance-based loopclosure detection method based on bags of visual words [1] which is able to detect when the robot has returned back to a previously visited place. An efficient optimization algorithm is used to integrate odometry information in this method to generate a consistent topo-metrical map. The resulting algorithm which only requires a monocular camera and odometry data and is simple, and robust without requiring any a priori information on the environment. Keywords—SLAM, monocular vision, odometry, mobile robot, topo-metrical map. I

Color-based underwater object recognition using water light attenuation

International audienceAbstract--In this article we present a new approach for object recognition in a robotic underwater context. Color is an attractive feature because of its simplicity and its robustness to scale changes, object positions and partial occlusions. Unfortunately, in the underwater medium, the colors are modified by attenuation and are not constant with the distance. To perform a color-based recognition of an object, we develop an algorithm robust with respect to the attenuation which takes into account the light modification during its path between the light source and the camera. Therefore, a given underwater object can be identified in an image by detecting all the colors compatible with its prior known color. Our method is fast, robust and needs a very few computers resources. We successfully used it when experimenting in the sea using a system we built. It is suitable for robotic applications where computers resources are limited and shared between various embedded devices. This novel concept enables the use of the color in many applications such as target interception, object tracking or obstacle detection

Comparison of high performance liquid chromatography and stereological image analysis for the quantitation of eumelanins and pheomelanins in melanoma cells.

The aim of the study was to compare two methods quantifying eumelanins and pheomelanins, pigments synthesized by melanocytes. One is based on the high performance liquid chromatography (HPLC) quantitation of specific degradation products of each melanin type. The other requires image analysis, transmission electron microscopy (TEM), and stereology. This study was carried out in cultured human melanoma cells and for each line, melanins were measured by HPLC and cells were fixed and embedded as pellets for TEM. Ultrathin sections were treated or not by the alkali elution method allowing the elimination of pheomelanins. The obtained micrographs were analyzed with our image analysis program permitting the estimation of several primary parameters. Stereology was used for estimating melanosomal maturation, intracellular melanins content, and number of melanized melanosomes per cell, for total melanin, eumelanins, or pheomelanins. Our results show a good correlation between both methods for total melanin, particularly when using the cytoplasmic volume density of melanin (r=0.93). Moreover, we report that the number of melanized melanosomes per cell and not the melanosomal maturation is responsible for the differences in total melanin content observed between the different cell lines. However, none of the stereological melanization parameters was correlated in the case of eumelanins or pheomelanins. In order to demonstrate the utter relevancy of this stereological approach, utilization of more pigmented melanoma cells, comparative study of HPLC and stereology, in normal epidermal melanocytes and a new evaluation of the alkali elution method in appropriate animal models would help us to explain the present results.Comparative StudyJournal ArticleResearch Support, Non-U.S. Gov'tinfo:eu-repo/semantics/publishe

Wide-field optical coherence tomography: imaging of biological tissues

We describe a two-dimensional optical coherence tomography technique with which we were able to obtain multiple longitudinal slices of a biological sample directly in a single Z scan. The system is based on a femtosecond Cr4+:forsterite laser and an infrared camera for wide-field imaging of the sample with a depth resolution of 5 µm. With this imaging apparatus we were able to investigate human skin and mouse ear samples and to observe the different constitutive tissues

Wide-field optical coherence tomography: Imaging of biological tissues at 1220 nm

A two-dimensional optical coherence tomography technique has been developed in order to obtain multiple longitudinal slices of a biological sample directly, in a single Z-scan. The system is based on a femtosecond Cr4+:Forsterite laser and an infrared camera for wide-field imaging of the sample with a depth resolution of 9 micrometers . With this imaging apparatus, we investigated biological tissues such as human skin, human tooth and a mouse ear to observe the different constitutive tissues of the samples

Wide-field optical coherence tomography: Imaging of biological tissues at 1220 nm

International audienceA two-dimensional optical coherence tomography technique has been developed in order to obtain multiple longitudinal slices of a biological sample directly, in a single Z-scan. The system is based on a femtosecond Cr4+:Forsterite laser and an infrared camera for wide-field imaging of the sample with a depth resolution of 9 micrometers . With this imaging apparatus, we investigated biological tissues such as human skin, human tooth and a mouse ear to observe the different constitutive tissues of the samples