Journal of the Korean Society of Marine Environment and Safety
A sensor is needed to continuously and automatically measure the change in HNS concentration in i... more A sensor is needed to continuously and automatically measure the change in HNS concentration in industrial facilities that directly discharge to the sea after water treatment. The basic function of the sensor is to be able to detect ppb levels even at room temperature. Therefore, a method for increasing the sensitivity of the existing sensor is proposed. First, a method for increasing the conductivity of a film using a conductive carbon-based additive in a nanoparticle thin film and a method for increasing ion adsorption on the surface using a catalyst metal were studied.. To improve conductivity, carbon black was selected as an additive in the film using ITO nanoparticles, and the performance change of the sensor according to the content of the additive was observed. As a result, the change in resistance and response time due to the increase in conductivity at a CB content of 5 wt% could be observed, and notably, the lower limit of detection was lowered to about 250 ppb in an experiment with organic solvents. In addition, to increase the degree of ion adsorption in the liquid, an experiment was conducted using a sample in which a surface catalyst layer was formed by sputtering Au. Notably, the response of the sensor increased by more than 20% and the average lower limit of detection was lowered to 61 ppm. This result confirmed that the chemical resistance sensor using metal oxide nanoparticles could detect HNS of several tens of ppb even at room temperature.
For marine accidents, prompt actions to minimize the casualties and loss of property are crucial.... more For marine accidents, prompt actions to minimize the casualties and loss of property are crucial. Remote sensing using satellites or aircrafts enables effective monitoring over a large area. Hyperspectral remote sensing allows the acquisition of high-resolution spectral information. This technology detects target objects by analyzing the spectrum for each pixel. We present a clustering method of seawater and floating objects by analyzing aerial hyperspectral images. For clustering, unsupervised learning algorithms of K-means, Gaussian Mixture, and DBSCAN are used. The detection performance of those algorithms is expressed as the precision, recall, and F1 Score. In addition, this study presents a color mapping method that analyzes the detected small object using cosine similarity. This technology can minimize future casualties and property loss by enabling rapid aircraft and maritime search, ocean monitoring, and preparations against marine accidents.
This paper demonstrates a commercial-level field-portable lens-free cell analyzer called the Navi... more This paper demonstrates a commercial-level field-portable lens-free cell analyzer called the NaviCell (No-stain and Automated Versatile Innovative cell analyzer) capable of automatically analyzing cell count and viability without employing an optical microscope and reagents. Based on the lens-free shadow imaging technique, the NaviCell (162 × 135 × 138 mm 3 and 1.02 kg) has the advantage of providing analysis results with improved standard deviation between measurement results, owing to its large field of view. Importantly, the cell counting and viability testing can be analyzed without the use of any reagent, thereby simplifying the measurement procedure and reducing potential errors during sample preparation. In this study, the performance of the NaviCell for cell counting and viability testing was demonstrated using 13 and six cell lines, respectively. Based on the results of the hemocytometer (de facto standard), the error rate (ER) and coefficient of variation (CV) of the NaviCell are approximately 3.27 and 2.16 times better than the commercial cell counter, respectively. The cell viability testing of the NaviCell also showed an ER and CV performance improvement of 5.09 and 1.8 times, respectively, demonstrating sufficient potential in the field of cell analysis.
The refractive index (RI), an important optical property of a material, is measured by commercial... more The refractive index (RI), an important optical property of a material, is measured by commercial refractometers in the food, agricultural, chemical, and manufacturing industries. Most of these refractometers must be equipped with a prism for light dispersion, which drastically limits the design and size of the refractometer. Recently, there have been several reports on the development of a surface plasmon resonance (SPR)-based RI detector, which is characterized by its high sensitivity and simplicity. However, regardless of the prism, an expensive spectrometer is required to analyze the resonance wavelength or angle of incidence. This paper proposes a method that eliminates the need for the prism and other conventional spectrometer components. For this purpose, total internal reflection SPR technology was used on an Ag thin film, and RI analysis was combined with a lens-free CMOS image sensor or a smartphone camera. A finite-difference time-domain (FDTD) numerical simulation was pe...
With an increase in the overseas maritime transport of hazardous and noxious substances (HNSs), H... more With an increase in the overseas maritime transport of hazardous and noxious substances (HNSs), HNS-related spill accidents are on the rise. Thus, there is a need to completely understand the physical and chemical properties of HNSs. This can be achieved through establishing a library of spectral characteristics with respect to wavelengths from visible and near-infrared (VNIR) bands to shortwave infrared (SWIR) wavelengths. In this study, a ground HNS measurement experiment was conducted for artificially spilled HNS by using two hyperspectral cameras at VNIR and SWIR wavelengths. Representative HNSs such as styrene and toluene were spilled into an outdoor pool and their spectral characteristics were obtained. The relative ratio of HNS to seawater decreased and increased at 550 nm and showed different constant ratios at the SWIR wavelength. Noise removal and dimensional compression procedures were conducted by applying principal component analysis on HNS hyperspectral images. Pure HN...
IGARSS 2020 - 2020 IEEE International Geoscience and Remote Sensing Symposium, 2020
Hazardous Noxious Substance (HNS) is transported entirely through large vessels, so there is alwa... more Hazardous Noxious Substance (HNS) is transported entirely through large vessels, so there is always a potential risk of marine HNS spills. In the event of an HNS accident, it can cause enormous human and property damage, so prompt detection is required. However, there is a limit to human access by ship, we need to use remote sensing data. In this study, ground experiments using hyperspectral cameras were performed to construct a spectral library of HNS. We classified the HNS and non-HNS by applying the hyperspectral mixture algorithm, and presented the HNS detection probability for every pixel by calculating the spectrum-based abundance fraction. The results of this study are expected to be used to estimate the extent of HNS spill in the event of a marine HNS accident.
Crude oil detection in the sea is an important task for the prevention of oil spill and the ocean... more Crude oil detection in the sea is an important task for the prevention of oil spill and the oceanic environment management. To measure the crude oil which is dissolved in the seawater, a sensor based on the fluorescence spectroscopy is widely used, because it is made up of hydrocarbon compounds. However, most of these sensors use an ultraviolet mercury lamp, several optical filters, and the photomultiplier tube (PMT). These components make the sensing platform large and expensive. To address these issues, we have developed the fluorometer, which is composed of optical devices having cost effectiveness and compact size, such as complementary metal-oxide-semiconductor (CMOS) image sensor and ultraviolet (UV) light-emitting diode (LED). In this paper, we provide the sensing platform, the principal sensing mechanism and the test results, which were obtained by an experiment using two different crude oils. Through these results, we can show the sensing performance of our novel fluoromete...
IGARSS 2019 - 2019 IEEE International Geoscience and Remote Sensing Symposium, 2019
In this study, the effect of hyperspectral atmospheric correction on accuracy of the ship detecti... more In this study, the effect of hyperspectral atmospheric correction on accuracy of the ship detection was investigated. We applied two atmospheric correction algorithms on airborne hyperspectral data and then detected ship features from reflectance corrected by each algorithms with an unsupervised target detection method. Both ATREM and FLAASH algorithms produce comparable atmospheric correction results but the algorithm which applied with further correction options optimized for coastal monitoring purpose reveals better detection results for ship detection. Compared to the result from ATREM, the result from FLAASH-corrected reflectance shows a distinct contrast between the ship and surrounding background seawater. Mean values of spectral angles between target and endmember spectra were 0.2388 (ATREM) and 0.2169 (FLAASH). This implies a further optimization of the atmospheric correction can improve the performance of target detection using airborne hyperspectral data, especially for maritime search purpose.
A new optical sensing method is proposed to detect hydrocarbon oil in the sea. As a sensing metho... more A new optical sensing method is proposed to detect hydrocarbon oil in the sea. As a sensing methodology, a light absorption analysis is used with a laser source and two different types of photodiode sensors. To obtain information about the presence of oil on water and the thickness of oil, the intensity of the penetrating light through the oil–water mixtures is measured. In the experiment, bunker C and lubricating oil are used, and three different lasers having different wavelengths are applied and compared for the selection of an optimal light source. By using a photodiode sensor, we can convert the intensity of the penetrating light through a liquid into an electrical signal. As a result, it is observed that the intensity of the light on the optical sensor decreases with an increase in the oil thickness. Through this relation, both the presence of oil and the thickness of oil can be determined. This result shows the applicability of a hydrocarbon detection sensor. Keywords—Optical...
In this research, we describe the concept of underwater oil spill imaging technology based on the... more In this research, we describe the concept of underwater oil spill imaging technology based on the UVinduced fluorescence. This imaging system is composed of the ultraviolet LED (Light Emitting Diode) lights and the CCD (Charge-Coupled Device) image sensor. For the identification of the proposed imaging system, we conducted the lab-scale validation tests to classify the difference between the oil samples and the background. For the comparison between oil samples and seawater, we analyzed the images acquired from tests which were performed in different conditions. Through these tests, we can visualize the shape of underwater oil and also distinguish the oil samples from seawater. From this experiment using the proposed setup, we can confirm the possibility of this system for the underwater oil spill imaging system by UV LEDinduced fluorescence. Keywords-Underwater oil; Oil spill imaging; UV LED; Fluorescence
As marine traffic has increased, the importance of ship detection using remote sensing images has... more As marine traffic has increased, the importance of ship detection using remote sensing images has been emphasized. Especially, with a better performance for discrimination of target, the usage of hyperspectral data for marine surveillance has been increasing recently. In this study, we detected the vessels on airborne hyperspectral images and quantitatively analyzed the detection results. To obtain the airborne hyperspectral images and auxiliary data for the quantitative validation, the in-field airborne imaging experiment was carried out. In addition, four different end-member extraction techniques including N-FINDR, PPI, ICA, and VCA were applied for comparison of detection performance with hyperspectral unmixing methods. Detection results present significant differences by endmember extraction techniques. The N-FINDR and VCA techniques presented a total of 14 vessels, while the ICA technique detected seven vessels, and the PPI technique detected two vessels. The pixel-based proba...
Journal of the Korean Society of Marine Environment and Safety
A sensor is needed to continuously and automatically measure the change in HNS concentration in i... more A sensor is needed to continuously and automatically measure the change in HNS concentration in industrial facilities that directly discharge to the sea after water treatment. The basic function of the sensor is to be able to detect ppb levels even at room temperature. Therefore, a method for increasing the sensitivity of the existing sensor is proposed. First, a method for increasing the conductivity of a film using a conductive carbon-based additive in a nanoparticle thin film and a method for increasing ion adsorption on the surface using a catalyst metal were studied.. To improve conductivity, carbon black was selected as an additive in the film using ITO nanoparticles, and the performance change of the sensor according to the content of the additive was observed. As a result, the change in resistance and response time due to the increase in conductivity at a CB content of 5 wt% could be observed, and notably, the lower limit of detection was lowered to about 250 ppb in an experiment with organic solvents. In addition, to increase the degree of ion adsorption in the liquid, an experiment was conducted using a sample in which a surface catalyst layer was formed by sputtering Au. Notably, the response of the sensor increased by more than 20% and the average lower limit of detection was lowered to 61 ppm. This result confirmed that the chemical resistance sensor using metal oxide nanoparticles could detect HNS of several tens of ppb even at room temperature.
For marine accidents, prompt actions to minimize the casualties and loss of property are crucial.... more For marine accidents, prompt actions to minimize the casualties and loss of property are crucial. Remote sensing using satellites or aircrafts enables effective monitoring over a large area. Hyperspectral remote sensing allows the acquisition of high-resolution spectral information. This technology detects target objects by analyzing the spectrum for each pixel. We present a clustering method of seawater and floating objects by analyzing aerial hyperspectral images. For clustering, unsupervised learning algorithms of K-means, Gaussian Mixture, and DBSCAN are used. The detection performance of those algorithms is expressed as the precision, recall, and F1 Score. In addition, this study presents a color mapping method that analyzes the detected small object using cosine similarity. This technology can minimize future casualties and property loss by enabling rapid aircraft and maritime search, ocean monitoring, and preparations against marine accidents.
This paper demonstrates a commercial-level field-portable lens-free cell analyzer called the Navi... more This paper demonstrates a commercial-level field-portable lens-free cell analyzer called the NaviCell (No-stain and Automated Versatile Innovative cell analyzer) capable of automatically analyzing cell count and viability without employing an optical microscope and reagents. Based on the lens-free shadow imaging technique, the NaviCell (162 × 135 × 138 mm 3 and 1.02 kg) has the advantage of providing analysis results with improved standard deviation between measurement results, owing to its large field of view. Importantly, the cell counting and viability testing can be analyzed without the use of any reagent, thereby simplifying the measurement procedure and reducing potential errors during sample preparation. In this study, the performance of the NaviCell for cell counting and viability testing was demonstrated using 13 and six cell lines, respectively. Based on the results of the hemocytometer (de facto standard), the error rate (ER) and coefficient of variation (CV) of the NaviCell are approximately 3.27 and 2.16 times better than the commercial cell counter, respectively. The cell viability testing of the NaviCell also showed an ER and CV performance improvement of 5.09 and 1.8 times, respectively, demonstrating sufficient potential in the field of cell analysis.
The refractive index (RI), an important optical property of a material, is measured by commercial... more The refractive index (RI), an important optical property of a material, is measured by commercial refractometers in the food, agricultural, chemical, and manufacturing industries. Most of these refractometers must be equipped with a prism for light dispersion, which drastically limits the design and size of the refractometer. Recently, there have been several reports on the development of a surface plasmon resonance (SPR)-based RI detector, which is characterized by its high sensitivity and simplicity. However, regardless of the prism, an expensive spectrometer is required to analyze the resonance wavelength or angle of incidence. This paper proposes a method that eliminates the need for the prism and other conventional spectrometer components. For this purpose, total internal reflection SPR technology was used on an Ag thin film, and RI analysis was combined with a lens-free CMOS image sensor or a smartphone camera. A finite-difference time-domain (FDTD) numerical simulation was pe...
With an increase in the overseas maritime transport of hazardous and noxious substances (HNSs), H... more With an increase in the overseas maritime transport of hazardous and noxious substances (HNSs), HNS-related spill accidents are on the rise. Thus, there is a need to completely understand the physical and chemical properties of HNSs. This can be achieved through establishing a library of spectral characteristics with respect to wavelengths from visible and near-infrared (VNIR) bands to shortwave infrared (SWIR) wavelengths. In this study, a ground HNS measurement experiment was conducted for artificially spilled HNS by using two hyperspectral cameras at VNIR and SWIR wavelengths. Representative HNSs such as styrene and toluene were spilled into an outdoor pool and their spectral characteristics were obtained. The relative ratio of HNS to seawater decreased and increased at 550 nm and showed different constant ratios at the SWIR wavelength. Noise removal and dimensional compression procedures were conducted by applying principal component analysis on HNS hyperspectral images. Pure HN...
IGARSS 2020 - 2020 IEEE International Geoscience and Remote Sensing Symposium, 2020
Hazardous Noxious Substance (HNS) is transported entirely through large vessels, so there is alwa... more Hazardous Noxious Substance (HNS) is transported entirely through large vessels, so there is always a potential risk of marine HNS spills. In the event of an HNS accident, it can cause enormous human and property damage, so prompt detection is required. However, there is a limit to human access by ship, we need to use remote sensing data. In this study, ground experiments using hyperspectral cameras were performed to construct a spectral library of HNS. We classified the HNS and non-HNS by applying the hyperspectral mixture algorithm, and presented the HNS detection probability for every pixel by calculating the spectrum-based abundance fraction. The results of this study are expected to be used to estimate the extent of HNS spill in the event of a marine HNS accident.
Crude oil detection in the sea is an important task for the prevention of oil spill and the ocean... more Crude oil detection in the sea is an important task for the prevention of oil spill and the oceanic environment management. To measure the crude oil which is dissolved in the seawater, a sensor based on the fluorescence spectroscopy is widely used, because it is made up of hydrocarbon compounds. However, most of these sensors use an ultraviolet mercury lamp, several optical filters, and the photomultiplier tube (PMT). These components make the sensing platform large and expensive. To address these issues, we have developed the fluorometer, which is composed of optical devices having cost effectiveness and compact size, such as complementary metal-oxide-semiconductor (CMOS) image sensor and ultraviolet (UV) light-emitting diode (LED). In this paper, we provide the sensing platform, the principal sensing mechanism and the test results, which were obtained by an experiment using two different crude oils. Through these results, we can show the sensing performance of our novel fluoromete...
IGARSS 2019 - 2019 IEEE International Geoscience and Remote Sensing Symposium, 2019
In this study, the effect of hyperspectral atmospheric correction on accuracy of the ship detecti... more In this study, the effect of hyperspectral atmospheric correction on accuracy of the ship detection was investigated. We applied two atmospheric correction algorithms on airborne hyperspectral data and then detected ship features from reflectance corrected by each algorithms with an unsupervised target detection method. Both ATREM and FLAASH algorithms produce comparable atmospheric correction results but the algorithm which applied with further correction options optimized for coastal monitoring purpose reveals better detection results for ship detection. Compared to the result from ATREM, the result from FLAASH-corrected reflectance shows a distinct contrast between the ship and surrounding background seawater. Mean values of spectral angles between target and endmember spectra were 0.2388 (ATREM) and 0.2169 (FLAASH). This implies a further optimization of the atmospheric correction can improve the performance of target detection using airborne hyperspectral data, especially for maritime search purpose.
A new optical sensing method is proposed to detect hydrocarbon oil in the sea. As a sensing metho... more A new optical sensing method is proposed to detect hydrocarbon oil in the sea. As a sensing methodology, a light absorption analysis is used with a laser source and two different types of photodiode sensors. To obtain information about the presence of oil on water and the thickness of oil, the intensity of the penetrating light through the oil–water mixtures is measured. In the experiment, bunker C and lubricating oil are used, and three different lasers having different wavelengths are applied and compared for the selection of an optimal light source. By using a photodiode sensor, we can convert the intensity of the penetrating light through a liquid into an electrical signal. As a result, it is observed that the intensity of the light on the optical sensor decreases with an increase in the oil thickness. Through this relation, both the presence of oil and the thickness of oil can be determined. This result shows the applicability of a hydrocarbon detection sensor. Keywords—Optical...
In this research, we describe the concept of underwater oil spill imaging technology based on the... more In this research, we describe the concept of underwater oil spill imaging technology based on the UVinduced fluorescence. This imaging system is composed of the ultraviolet LED (Light Emitting Diode) lights and the CCD (Charge-Coupled Device) image sensor. For the identification of the proposed imaging system, we conducted the lab-scale validation tests to classify the difference between the oil samples and the background. For the comparison between oil samples and seawater, we analyzed the images acquired from tests which were performed in different conditions. Through these tests, we can visualize the shape of underwater oil and also distinguish the oil samples from seawater. From this experiment using the proposed setup, we can confirm the possibility of this system for the underwater oil spill imaging system by UV LEDinduced fluorescence. Keywords-Underwater oil; Oil spill imaging; UV LED; Fluorescence
As marine traffic has increased, the importance of ship detection using remote sensing images has... more As marine traffic has increased, the importance of ship detection using remote sensing images has been emphasized. Especially, with a better performance for discrimination of target, the usage of hyperspectral data for marine surveillance has been increasing recently. In this study, we detected the vessels on airborne hyperspectral images and quantitatively analyzed the detection results. To obtain the airborne hyperspectral images and auxiliary data for the quantitative validation, the in-field airborne imaging experiment was carried out. In addition, four different end-member extraction techniques including N-FINDR, PPI, ICA, and VCA were applied for comparison of detection performance with hyperspectral unmixing methods. Detection results present significant differences by endmember extraction techniques. The N-FINDR and VCA techniques presented a total of 14 vessels, while the ICA technique detected seven vessels, and the PPI technique detected two vessels. The pixel-based proba...
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