Photo Camera Research Articles

Temperature Drives Summer Group Size Dynamics of Eastern Migratory Caribou in the Hudson Bay Lowlands of Manitoba

Aggregation behavior is pervasive across a broad range of animals and the outcome of this behaviour has both risks and rewards. Large aggregations of animals are a distinctive characteristic of Migratory Caribou (Rangifer tarandus Linnaeus, 1758), primarily in response to the environment factors such as predation, although caribou may also aggregate during high summer temperatures, likely in an effort to mitigate parasitic biting flies. To see if caribou in the Cape Churchill Caribou Herd of the Eastern Migratory caribou (Rangifer tarandus groenlandicus Borowski, 1780) Designatible Unit, also displayed aggregation behavior in relation to warmer summer temperatures, we collected trail camera photos with associated temperature readings during the summer period (May to September) from 2017 to 2020 in their summer range in Wapusk National Park, Manitoba, Canada. We found that summer caribou aggregation size was positively associated with ambient temperature, with aggregations increasing in size as temperature increased. The mechanism behind this behaviour should be investigated, as we predict more frequent and large caribou aggregations as summer temperatures continue to warm.

Improving Real-Scene 3D Model Quality of Unmanned Aerial Vehicle Oblique-Photogrammetry with a Ground Camera

In UAV (unmanned aerial vehicle) oblique photogrammetry, the occlusion of ground objects, particularly at their base, often results in low-quality real-scene 3D models. To address this issue, we propose a method to enhance model quality by integrating ground-based camera images. This innovative image acquisition method allows the rephotographing of areas in the 3D model that exhibit poor quality. Three critical parameters for reshooting are the reshooting distance and the front- and side-overlap ratios of reshooting images. The proposed method for improving 3D model quality focuses on point accuracy, dimensional accuracy, texture details, and the triangular mesh structure. Validated by a case study involving a complex building, this method demonstrates that integrating ground camera photos significantly improves the overall quality of the 3D model. The findings show that optimal settings for reshooting include a distance (in meter units) of 1.5–1.6 times the camera’s focal length (in millimeter units), a front overlap ratio of 30%, and a side overlap ratio of 20%. Furthermore, we conclude that an overlap rate of 20–30% in reshooting is a usable value.

Characterisation of the Glare Properties of Photovoltaic Modules and PV Systems Using a Photographic Camera

With the increasing prevalence of photovoltaic (PV) installations on north-facing roofs in urban areas, the issue of glare on PV modules is becoming more significant. This paper presents a method for measuring and characterising the intensity and type of glare using a commercially available photo camera. The method utilises the fact that brightness information is inherently contained in a photograph. Due to the strong non-linearity of brightness information in an image, especially when using High Dynamic Range (HDR) functionality, an image needs to be divided into multiple sub-images with clearly defined settings, and the linear range extracted from each of them. The information obtained in this way is then assembled into a new image. The resulting luminance image describes the intensity and shape of glare, forming the basis for calculating the occurrence of glare (times and days of the year) in a simplified manner.

Factors influencing haulout behaviour of non-breeding weddell seals (Leptonychotes weddellii) at Cape Royds, Antarctica

The Weddell seal (Leptonychotes weddellii) is a fast-ice obligate species that plays an important role as both predator and prey within the high-latitude, coastal Southern Ocean. Weddell seals are affected by pressures of marine resource extraction and variation in sea-ice extent and characteristics that are affected by climate. Thus, monitoring their population dynamics provides an indicator of the effectiveness of fisheries management, and impacts of changing climate in the high latitude Southern Ocean ecosystem. Satellite imagery is increasingly being used to monitor the populations of this species, but assessment techniques require a better understanding of the environmental factors influencing the likelihood that individuals will be on the sea-ice and therefore visible in a satellite image. Addressing that goal, we captured 5054 trail camera photos during spring 2017 in the 24-h light at Cape Royds, Antarctica, and then counted seals on the fast ice every 30 min over 59 days. Using a generalised additive model (63% deviance explained) we described the haulout behaviour of non-breeding Weddell seals according to time of day, date, air temperature, pressure, solar radiation, and wind speed. We found that the seals’ haulout cycle is driven to a significant degree by weather variables, primarily temperature and wind speed. Quantifying these haulout patterns can be used to determine the time of day, and under what conditions, that most seals are hauled out. Integrating environmental parameters to correct time-of-day patterns would allow better cross-site abundance comparisons, leading to better Weddell seal population estimates for the Ross Sea region and the wider coastal Antarctica.

Analysis of survival and morphometric parameters of loach embryos and prelarvae under the action of the polyethyleneglycol derivative polymeric nanocarrier

Background. Our previous studies have shown a minor embryotoxic effect of polymeric poly(VEP-co-GMA)-graft-mPEG carrier on Missgurnus fossilis L. embryos and prelarvae. At the same time, it was found that a 3-day exposure to 10-15 M polymer carrier slowed developing, which is characterized by a delayed hatching of larvae. However, in the 10-day experiment on loach larvae exposed to polymeric carrier, anomalies and defects of development have not been identified. The aim of this work was to analyze the embryos and prelarvae survival, as well as determine the morphometric indicators of the loach embryos under the action of a PEG-modified polymer carrier. Materials and Methods. Ovulation in loach females (Misgurnus fossilis L.) was stimulated by intramuscular injection of female chorionic gonadotropin (500 units), eggs were obtained 36 h after stimulation, fertilized in Petri dishes with a suspension of sperm according to A. A. Neifach. The stages of development were observed visually under a binocular microscope MBS-9 with a photo camera in a real-time mode. The experimental embryos were incubated in Goltfreter’s solution with the addition of PEG-containing carrier to a final concentration of 10 and 100 μmol/L. The morphological development of the embryo groups was evaluated according to the T. Fujimoto deve­lopment tables (2004), and the morphological parameters (diameter and area of roes, blastomers, embryos, embryo sac and blastodisk) were measured using ImageJ and Photoshop (CC 2014v15) programs. Results. Addition of the 10 μmol/L PEG-containing carrier to the medium initiated significant positive changes in the survival of loach embryos and prelarvae, in contrast to exposure to 100 μmol/L carrier. A significant increase in the area and diameter of blastomers and the embryos themselves under the influence of 100 μmol/L PEG carrier was established, which may indicate swelling of the embryos and a disruption of water-salt exchange that causes the early death of embryos. Conclusions. (1) Low embryotoxicity of the PEG-polymer was confirmed on the studied model of the loach embryos. Based on the obtained data and the original data of J. Maes et al. (2) PEG is an attractive polymeric carrier for the delivery of a variety of compounds to both embryos and prelarvae as well as other model subjects. Despite the fact that we investigated only two concentrations of the PEG-containing carrier, it is quite likely that these concentrations of the carrier are (3) biologically active in themselves and, therefore, a thorough selection of the PEG-carrier concentration for each objective of the model is needed.

Fusion of Multimodal Imaging and 3D Digitization Using Photogrammetry.

Multimodal sensors capture and integrate diverse characteristics of a scene to maximize information gain. In optics, this may involve capturing intensity in specific spectra or polarization states to determine factors such as material properties or an individual's health conditions. Combining multimodal camera data with shape data from 3D sensors is a challenging issue. Multimodal cameras, e.g., hyperspectral cameras, or cameras outside the visible light spectrum, e.g., thermal cameras, lack strongly in terms of resolution and image quality compared with state-of-the-art photo cameras. In this article, a new method is demonstrated to superimpose multimodal image data onto a 3D model created by multi-view photogrammetry. While a high-resolution photo camera captures a set of images from varying view angles to reconstruct a detailed 3D model of the scene, low-resolution multimodal camera(s) simultaneously record the scene. All cameras are pre-calibrated and rigidly mounted on a rig, i.e., their imaging properties and relative positions are known. The method was realized in a laboratory setup consisting of a professional photo camera, a thermal camera, and a 12-channel multispectral camera. In our experiments, an accuracy better than one pixel was achieved for the data fusion using multimodal superimposition. Finally, application examples of multimodal 3D digitization are demonstrated, and further steps to system realization are discussed.

Free boundary equilibrium determination of HL-3 discharges

In 2022–2023, HL-3 (previously known as HL-2M) realized the divertor discharge after its first plasma campaign. To analyze equilibrium configurations of HL-3, a free boundary equilibrium code FEEQS, based on the finite element method, has been used in recent experiments. Free boundary equilibrium determinations are carried out for discharges performed in both limiter and divertor configurations. Compared with the experimental diagnostic data from fast camera photos and saturated ion current signals.etc, various time evolution of plasma parameters are well reproduced, such as plasma shape, currents in the poloidal field coils, strike-point displacement. The use of FEEQS successfully supported the operations in HL-3, and physics study as well, which laid a foundation for the application of free boundary equilibrium integration simulation in the next step.

Pulse-width modulation as a new hygienic factor determining the visual comfort of modern screens

The information revolution and intensive development of electronic devices take place in the recent decades. Furthermore, not so long ago such a hygienic factor, as the display luminance pulse-width modulation (PWM) capable of causing visual discomfort (PWM symptoms) in individuals with increased sensitivity to visual load, has become relevant. The main complaints include eye pain, headache, sometimes nausea, up to the inability to use such screens. Moreover, this characteristic can be peculiar not only to LED (AMOLED, etc.), but also to IPS displays due to the presence of the LED backlight layer. No regulation of the issue has led to the emergence of online resources on PWM and the problem of visual impairment, where users verify the data on their own, which suggests the relevance of the subject selected. The paper reports theoretical aspects of PWM, technical characteristics of displays with PWM; the approaches to PWM measurement are described; the possible ways to reduce visual discomfort are discussed. Furthermore, the paper describes the method to measure PWM of displays using a photo camera with the exposure time set to 1/20 s, along with the method testing results. It has been shown that further research focused on assessing the effects of PWM on vision and the development of the method for hygienic assessment of monitors and smartphone screens with PWM are required.

Цифровой сглаживающий трапецеидальный рекурсивно-сепарабельный фильтр обработки изображений с изменяемыми размерами сканирующей многоэлементной апертуры

The development of television systems is an important factor for many industries involved in the acquisition, processing, storage and transmission of images. Today, an urgent task in the use of such systems is to improve the quality of images obtained using digital photo and video cameras. To solve this problem, digital recursive-separable smoothing filters can be used. The paper describes the process of operation of the algorithm for changing the size of the scanning multi-element aperture of a smoothing trapezoidal recursive-separable filter for digital image processing. The results of evaluating its performance relative to the same algorithm implemented through classical two-dimensional convolution for various sizes of test images are presented. The influence of the aperture size of the developed filter on the change in the signal-to-noise ratio is assessed. The algorithm is implemented in the MATLAB computing environment.

Predation of the endangered Ae'o (Hawaiian Stilt) by a native raptor, the Pueo (Hawaiian Short-eared Owl) on the island of O'ahu, Hawai'i, USA.

While the impact of introduced predators is a widely acknowledged issue and key component of conservation considerations for endemic waterbird populations in the Hawaiian Islands, the impact of native predators on endemic, endangered waterbirds is not as frequently discussed or factored into recovery models. The Pueo (Hawaiian Short-eared Owl; Asio flammeus sandwichensis) is a subspecies of Short-eared Owl endemic to the Hawaiian Islands and is State-listed as Endangered on the island of O'ahu. The Ae'o (Hawaiian Stilt; Himantopus mexicanus knudensi) is a subspecies of the Black-necked Stilt endemic to Hawai'i and is federally listed as Endangered throughout its range. A variety of non-native predators are confirmed to consume Ae'o eggs, chicks, and adults, including invasive mammals (e.g., feral cats), birds (e.g., Barn Owls), and amphibians (e.g., bullfrogs). While predation by native predators was suspected, there are no cases documented in the literature to date describing Pueo preying upon Ae'o. Here, we describe four events that provide evidence of Pueo predating Ae'o during the 2019-2021 breeding seasons in a wetland area on the island of O'ahu: (1) confirmed Pueo predating an Ae'o chick, (2) a suspected predation attempt of a Pueo chasing adult Ae'o, and (3) two suspected predation events based on (a) 10 adult-sized Ae'o carcasses and remains found near an active Pueo nest and (b) game camera photos of Pueo visiting two Ae'o nests. To our knowledge, these novel observations are the first published accounts of predator-prey interactions between these two subspecies.

Craniofacial 3D Morphometric Analysis with Smartphone-Based Photogrammetry.

Obtaining 3D craniofacial morphometric data is essential in a variety of medical and educational disciplines. In this study, we explore smartphone-based photogrammetry with photos and video recordings as an effective tool to create accurate and accessible metrics from head 3D models. The research involves the acquisition of craniofacial 3D models on both volunteers and head mannequins using a Samsung Galaxy S22 smartphone. For the photogrammetric processing, Agisoft Metashape v 1.7 and PhotoMeDAS software v 1.7 were used. The Academia 50 white-light scanner was used as reference data (ground truth). A comparison of the obtained 3D meshes was conducted, yielding the following results: 0.22 ± 1.29 mm for photogrammetry with camera photos, 0.47 ± 1.43 mm for videogrammetry with video frames, and 0.39 ± 1.02 mm for PhotoMeDAS. Similarly, anatomical points were measured and linear measurements extracted, yielding the following results: 0.75 mm for photogrammetry, 1 mm for videogrammetry, and 1.25 mm for PhotoMeDAS, despite large differences found in data acquisition and processing time among the four approaches. This study suggests the possibility of integrating photogrammetry either with photos or with video frames and the use of PhotoMeDAS to obtain overall craniofacial 3D models with significant applications in the medical fields of neurosurgery and maxillofacial surgery.

Comparison of modern 3D measurement methods for special tasks of shipbuilding industry

Research presents modern technologies of 3D measurements in shipbuilding production parts. Special template of the keel detail was made for the research. The detail measurements with a laser tracker, laser scanning, industrial photogrammetry and handheld scanning are performed. Leica Absolute Tracker AT960-LR was used for Laser tracker measurements. Laser scanning was performed with Z+F Imager 5010. Nikon D2Xs photo camera was used for Industrial photogrammetry. Handheld scanner DPI-7 from DotProduct was also used for 3D measurements of the details. All collected data were imported into 3DReshaper software for comparison. The accuracy comparison for the specific equipment used in the study is performed. The recommendations for optimal equipment use and software products in this research are also included. The authors also present the assessment of the cost and time spent on the measurements.

Direct Environmental Lead Detection by Photoluminescent Perovskite Formation with Nanogram Sensitivity.

Although the global ban on leaded gasoline has markedly reduced lead poisoning, many other environmental sources of lead exposure, such as paint, pipes, mines, and recycling sites remain. Existing methods to identify these sources are either costly or unreliable. We report here a new, sensitive, and inexpensive lead detection method that relies on the formation of a perovskite semiconductor. The method only requires spraying the material of interest with methylammonium bromide and observing whether photoluminesence occurs under UV light to indicate the presence of lead. The method detects as little as 1.0 ng/mm2 of lead by the naked eye and 50 pg/mm2 using a digital photo camera. We exposed more than 50 different materials to our reagent and found no false negatives or false positives. The method readily detects lead in soil, paint, glazing, cables, glass, plastics, and dust and could be widely used for testing the environment and preventing lead poisoning.

ИССЛЕДОВАНИЕ ОБЪЕКТОВ, ПРЕДСТАВЛЯЮЩИХ ЭКОЛОГИЧЕСКУЮ УГРОЗУ, В ЗАЛИВЕ ЦИВОЛЬКИ (НОВАЯ ЗЕМЛЯ, КАРСКОЕ МОРЕ)

The article presents results of field studies of the environmental assessment of the bays of the eastern coast of Novaya Zemlya in connection with potentially dangerous objects flooded in this region, which are the nuclear fleet operation waste products. In the course of these studies, technology was used based on remote-controlled and towed uninhabited underwater vehicles (ROV and UTSI), as well as side-view sonar (SSS) developed at IO RAS. To detail information about the condition of emergency facilities and operational waste flooded in 60 years at Tsivolki bay, a deep-water UTSI “Video Module” was used. It is equipped with video and photo cameras, a high-frequency SSS, a depth gauge, an altimeter, a laser scale pointer, as well as auxiliary equipment that ensures the functioning of research systems. Observations in the Gulf of Tsivolki using instrumental technologies made it possible to identify underwater objects whose existence was known only from archival data. Monitoring of the condition of objects was provided using RAM-family gamma-ray spectrometers developed at the Kurchatov Institute Research Center. The nature of the recorded gamma-ray spectra generally corresponds to the measurement results obtained during the assembly survey in 2010 and 2015, and indicates the integrity of the internal protective barriers.

Sakato Plate Dance Choreography at Nagari Abai

The purpose of this study was to describe and analyze the Choreography of Sakato Plate Dance in Nagari Abai. The object of research studied was Sakato Plate Dance in Abai Sakato Art Studio, Nagari Abai. Stationery is used to record information or data obtained from sources and information related to Sakato Plate Dance. Photo Camera to take pictures of the form of motion and everything related to Sakato Plate Dance. Audio Recorder, this tool is used to record information about dance history, background, dance music and other information from informants and sources about Piring Sakato Dance. Primary data, namely data obtained from the main source, namely the choreographer of Sakato Plate Dance. Secondary data, which is supporting research data obtained through data that has been collected or the results of relevant research, then the data is also obtained from documentation owned by the Sakato Plate Dance choreographer in the form of photos, video recordings and others. The analysis steps taken are, the data is selected as needed and related to the problem posed, namely about the Sakato Plate Dance Choreography then arranged systematically and descriptively. The energy aspect used in this Sakato Plate Dance is that there is slow, medium, and strong energy this aspect aims to beautify the Sakato Plate Dance. As for the interaction that occurs in the Sakato Plate Dance, the property used in this Sakato Plate Dance is a plate with a plate size of 5. The clothes used in the Sakato Plate Dance are costumes that have been created so that dancers are easy to make movements and are not disturbed when holding plates.

Comparative study of means of mathematical communication in Japan, Laos, and Thailand

This comparative study analyzed the similarities and differences in the mathematical communication used by teachers and primary school students in Japanese, Lao, and Thai mathematics classrooms. It adopted a qualitative research design, and the targets were teachers and students in Grades 1 - 6 at a selected school in each of the three countries. The data were collected from one classroom at each grade level from the three schools, so eighteen classrooms were involved in the study. The research tools included video recorders, photo cameras, and a field notes form. The data were analyzed by employing the analytical descriptive method based on Pirie's conceptual framework of the means of mathematical communication (1998). The findings revealed that the means of mathematical communication in the three countries were similar in their use of ordinary, mathematical, verbal, and symbolic language—differences in the means of mathematical communication related to how varied the learning materials were. The Japanese classrooms used the most varied means of mathematical communication, demonstrating all six means, while the Thai classrooms used only 5, and the Lao PDR classrooms used only 4. The Japanese classrooms were shown to be focused on the students' diverse self-solution concepts, while some of the Thai and Lao PDR classrooms were based on question-answer interactions between the teachers and students.

Smartphone-based spectroscopy as a tool to estimate soil attributes for the citizen science concept

This study explores the potential of using smartphone cameras to estimate soil attributes as a field-based alternative to traditional sampling and lab analyses that are time-consuming, expensive, and non-friendly to the environment. It aims to investigate whether the color information captured by smartphone cameras could provide spectral information that can be utilized for soil attribute estimation using regression techniques. The DN values from smartphone camera photos were transformed into reflectance using colored plastic plated marker (PPM) reference panels. The spectral information of the PPM keys, obtained using a laboratory spectrometer, was convolved into 3 RGB smartphone bands. Using the legacy soil spectral library (SSL) of Israel on the 3-reflectance calibrated RGB smartphone bands, a good agreement with the reflectance of the laboratory spectrometer was obtained. The soil properties were modeled with the converted reflectance using the multiple linear regression (MLR), partial least square regression (PLSR), and ridge regression (RR) algorithms. The models created using the smartphone data (RGB and 6 synthetic bands) predicted six soil properties: i.e., soil organic matter (OM%), CaCO3, free iron oxides (Fe-dithionite), Al2O3, soil surface area (SSA), and hygroscopic moisture with the coefficient of determination (R2) values of 0.58, 0.54, 0.60, 0.55, 0.55 and 0.64, respectively. The quality of predictions was also evaluated using root mean square error (RMSE) and the ratio of prediction to interquartile distance (RPIQ). This research provides the results of an experiment to convert a personal smartphone camera to a spectrometer with the help of SSL. Despite the low spectral resolution of smartphone cameras, the models achieved fair results in predicting six soil properties. These findings could promote the adoption of citizen science methodologies for sustainable soil management as smartphone devices that are available to all can be simply calibrated to reflectance and used for proximal sensing of soils.

Technology to Automatically Record Eating Behavior in Real Life: A Systematic Review.

To monitor adherence to diets and to design and evaluate nutritional interventions, it is essential to obtain objective knowledge about eating behavior. In most research, measures of eating behavior are based on self-reporting, such as 24-h recalls, food records (food diaries) and food frequency questionnaires. Self-reporting is prone to inaccuracies due to inaccurate and subjective recall and other biases. Recording behavior using nonobtrusive technology in daily life would overcome this. Here, we provide an up-to-date systematic overview encompassing all (close-to) publicly or commercially available technologies to automatically record eating behavior in real-life settings. A total of 1328 studies were screened and, after applying defined inclusion and exclusion criteria, 122 studies were included for in-depth evaluation. Technologies in these studies were categorized by what type of eating behavior they measure and which type of sensor technology they use. In general, we found that relatively simple sensors are often used. Depending on the purpose, these are mainly motion sensors, microphones, weight sensors and photo cameras. While several of these technologies are commercially available, there is still a lack of publicly available algorithms that are needed to process and interpret the resulting data. We argue that future work should focus on developing robust algorithms and validating these technologies in real-life settings. Combining technologies (e.g., prompting individuals for self-reports at sensed, opportune moments) is a promising route toward ecologically valid studies of eating behavior.

High-Speed Flow Visualization by a Nanosecond Volume Discharge during Shock Wave Diffraction on an Obstacle

We study the spatial structure of nonstationary inhomogeneous supersonic airflows as shock wave diffraction on an obstacle occurs in a shock tube of a rectangular cross section. The Mach numbers of shock waves were 2.7–4.4 at initial air pressures of 10–30 Torr. The supersonic flow in the discharge chamber was visualized by high-speed shadowgraphy and by the registration of radiation of combined volume discharge by photo camera and by ICCD camera. In experiments, a combined volume discharge with a current duration of ~ 500 ns was initiated 40–150 μs after the initial shock wave have passed an obstacle. It has been established that the radiation of the volume phase of discharge lasts 400–700 ns, and the displacement of the flow during this time does not exceed 0.6 mm. A correlation is established between the spatial distribution of discharge radiation and the low-density local areas determined as a result of two-dimensional Navier-Stokes based numerical simulation of the flow. As visualized by the glow of the discharge, the shape of the shock wave front is in good agreement with the results of shadowgraphy at different stages of diffraction and with the numerical simulation results.

Abundant off-axis hydrothermal activity in the 29–30 ridge segment of the Southwest Indian Ridge: evidence from ferromanganese crusts

In the ultra-slow spreading mid-ocean ridge, seafloor hydrothermal ventings mostly occur in the off-axis region. The plume of hydrothermal venting provides Fe, Mn and other metal materials for the growth of ferromanganese crust in the surrounding seamounts, showing unique geochemical characteristics that are different from that of hydrogenetic crust. Based on five samples of ferromanganese crusts, major, trace and rare earth element analysis was carried out to identify their material sources. Combined with the investigation data of water column and seafloor camera photos by deep towed hydrothermal detection system, the potential of hydrothermal activity in the 29–30 ridge segment of the Southwest Indian ridge was evaluated. The results showed that the ferromanganese crust in the study area had significantly higher Fe/Mn value (average 1.9), relatively higher Si and Al contents, and significantly higher Ca/P value (average 9.3),without significant phosphorylation. ferromanganese crust in the study area have significantly lower Co and Ni contents (about 1600 mg/kg on average), and relatively lower Sr, Ba, Pb, Cu, Zr and Mo contents (between 100-1000 mg/kg on average). The contents of W, Th and Te are also relatively low (average content between 10–50 mg/kg); The total rare earth element content of the crust in the study area is relatively low (about 928 mg/kg on average), and the light rare earth is relatively enriched. The standardized rare earth curve of the shale shows a left-leaning pattern as a whole, showing the enrichment of heavy rare earth relative to the shale. The Co content and rare earth element content of the ferromanganese crusts in this area are significantly lower than those of hydrogenetic crusts. The discrimination diagrams of ternary and bivariate material sources reveal that they have mixed hydrothermal and hydrogenetic origins. The three crust samples of S1, S2, and S5 are located within 2 km of the known hydrothermal fields, indicating a correlation between ferromanganese crust and the location of hydrothermal activity. There is no known hydrothermal field near the S3 and S4 stations. Altered rocks and water column turbidity anomalies were found near S3 station, and large areas of altered rocks and suspected hydrothermal biological remains were also found near S4 station, indicating that hydrothermal activity may exist in both areas. In addition to the two new hydrothermal fields identified in this article, the spatial frequency of hydrothermal activity in the study area reaches 15 sites/100 km, which is significantly higher than other well investigated oceanic ridges. Out of the eight hydrothermal fields in the study area, seven are located in the off axis region, mainly because the hydrothermal activity in this area is controlled by high angle and large offset normal faults and one-way detachment faults. This also indicates that the off-axis region of the Southwest Indian Ridge has high potential for hydrothermal activity.