PCB Patterns Research Articles

Contamination status by persistent organic pollutants of the Atlantic spotted dolphin (Stenella frontalis) at the metapopulation level.

The Atlantic spotted dolphin (Stenella frontalis) is an endemic species of the tropical-temperate Atlantic Ocean with widespread distribution. Although this species has been the subject of a large number of studies throughout its range, it remains in the "data deficient" category of the International Union for Conservation of Nature (IUCN). Chemical pollution by persistent organic pollutants (POPs) has been listed as one of the major threats to this species, however, there is no information on a wide scale. Thus, the aim of the present study was to investigate the contamination status of spotted dolphins on the metapopulation level as well as determine spatial and temporal variations in POP concentrations and bio-accumulation. A total of 115 blubber samples collected from a large part of the Atlantic basin were analysed for PCBs, DDTs, PBDEs, chlordanes, HCB and mirex. Although PCBs and DDTs were the predominant compounds in all areas, inter-location differences in POP concentrations were observed. Dolphins found at São Paulo, southeastern coast of Brazil, had the highest PCB concentrations (median: 10.5 μg/g lw) and Canary Islands dolphins had the highest DDT concentrations (median: 5.13 μg/g lw). Differences in PCB patterns among locations were also observed. Dolphins from the Azores and São Paulo demonstrated a similar pattern, with relatively highly contributions of tetra- (6.8 and 5.2%, respectively) and penta-CBs (25.6 and 23.8%, respectively) and lower contributions of hepta-CBs (20.8 and 23.5%, respectively) in comparison to other areas. Moreover, the sex of the animals and the year in which sampling or capture occurred exerted an important influence on the majority of the POPs analysed. Comparisons with toxicity thresholds available in the literature reveal that the São Paulo and Canary Island dolphins are the most vulnerable populations and should be considered in future conservation and management programs for the Atlantic spotted dolphin.

Reprint of: Long-range atmospheric transport of PAHs, PCBs and PBDEs to the central and eastern Mediterranean and changes of PCB and PBDE congener patterns in summer 2010

The central and eastern Mediterranean is a receptor area for persistent organic pollutants (POPs) emitted in western, central and eastern Europe, particularly during summer. Atmospheric concentrations of PCBs, DDXs, PBDEs, penta- and hexachlorobenzene were measured during a ship-borne survey in the summer of 2010. The concentration of PCBs (sum of 7 congeners) was 3.61 (2.08–7.72) pg m−3, of which 6.7% was associated with the particulate phase. The mean concentration of DDT isomers and their metabolites, DDE and DDD, was 2.60 (0.46–7.60) pg m−3 (particulate mass fraction θ = 0.097), of penta- and hexachlorobenzene 0.22 (<0.39–2.80) pg m−3 and 6.29 (2.48–24.16) pg m−3, respectively, and of PBDEs (sum of 8 congeners) 7.31 (2.80–19.89) pg m−3. The air masses studied had been transported mostly across central Europe, some crossing western Europe. The observed changes of PCB congener patterns along transport routes are in agreement with the perception that the reaction with the OH radical is dominating PCB atmospheric lifetime, and indicate an overestimation of the second order gas-phase reaction rate coefficient of PCB153 with OH by structure-activity relationship.

Long-range atmospheric transport of PAHs, PCBs and PBDEs to the central and eastern Mediterranean and changes of PCB and PBDE congener patterns in summer 2010

The central and eastern Mediterranean is a receptor area for persistent organic pollutants (POPs) emitted in western, central and eastern Europe, particularly during summer. Atmospheric concentrations of PCBs, DDXs, PBDEs, penta- and hexachlorobenzene were measured during a ship-borne survey in the summer of 2010. The concentration of PCBs (sum of 7 congeners) was 3.61 (2.08–7.72) pg m−3, of which 6.7% was associated with the particulate phase. The mean concentration of DDT isomers and their metabolites, DDE and DDD, was 2.60 (0.46–7.60) pg m−3 (particulate mass fraction θ = 0.097), of penta- and hexachlorobenzene 0.22 (<0.39–2.80) pg m−3 and 6.29 (2.48–24.16) pg m−3, respectively, and of PBDEs (sum of 8 congeners) 7.31 (2.80–19.89) pg m−3. The air masses studied had been transported mostly across central Europe, some crossing western Europe. The observed changes of PCB congener patterns along transport routes are in agreement with the perception that the reaction with the OH radical is dominating PCB atmospheric lifetime, and indicate an overestimation of the second order gas-phase reaction rate coefficient of PCB153 with OH by structure-activity relationship.

Distribution and sources of PCBs (Aroclor 1268) in the Sapelo Island National Estuarine Research Reserve

Aroclor 1268 is a highly chlorinated PCB mixture that was released into the aquatic environment near Brunswick, GA (BR), as a result of decades of local industrial activity. This extensive contamination has led to US EPA Superfund designation in estuarine areas in and around Purvis Creek, GA. Roughly 50km to the northeast is the Sapelo Island National Estuarine Research Reserve (SI) where previous studies have documented unexpectedly high Aroclor 1268-like PCB levels in blubber and plasma samples of resident bottlenose dolphins. This result led to a collaborative effort to assess the PCB patterns and concentrations in SI sediment and fish (as potential vectors for PCB transfer to SI resident dolphins). Thirty SI randomly assigned stations were sampled for sediment PCB levels. Additionally, fish were collected and analyzed from SI (n = 31) and BR (n = 33). Results were pooled with regional assessments of PCB concentrations from South Carolina and North Carolina in an effort to determine the association of Aroclor 1268 levels in SI samples. Results indicated that PCB levels in sediment and fish are much lower in the SI estuary compared to BR sediment and fish concentrations. However, PCB congener profiles for both sediments and fish were similar between the two locations and consistent with the Aroclor 1268 signature, indicating possible transport from the Brunswick area. A likely source of Aroclor 1268 in dolphins from SI is contaminated fish prey.

The role of diet on long-term concentration and pattern trends of brominated and chlorinated contaminants in western Hudson Bay polar bears, 1991–2007

Adipose tissue was sampled from the western Hudson Bay (WHB) subpopulation of polar bears at intervals from 1991 to 2007 to examine temporal trends of PCB and OCP levels both on an individual and sum-(∑-)contaminant basis. We also determined levels and temporal trends of emerging polybrominated diphenyl ethers (PBDEs), hexabromocyclododecane (HBCD), polybrominated biphenyls (PBBs) and other current-use brominated flame retardants. Over the 17-year period, ∑ DDT (and p,p′-DDE, p,p′-DDD, p,p′-DDT) decreased (−8.4%/year); α-hexachlorocyclohexane (α-HCH) decreased (−11%/year); β-HCH increased (+ 8.3%/year); and ∑ PCB and ∑ chlordane (CHL), both contaminants at highest concentrations in all years (> 1 ppm), showed no distinct trends even when compared to previous data for this subpopulation dating back to 1968. Some of the less persistent PCB congeners decreased significantly (−1.6%/year to −6.3%/year), whereas CB153 levels tended to increase (+ 3.3%/year). Parent CHLs ( c-nonachlor, t-nonachlor) declined, whereas non-monotonic trends were detected for metabolites (heptachlor epoxide, oxychlordane). ∑ chlorobenzene, octachlorostyrene, ∑ mirex, ∑ MeSO 2-PCB and dieldrin did not significantly change. Increasing ∑ PBDE levels (+ 13%/year) matched increases in the four consistently detected congeners, BDE47, BDE99, BDE100 and BDE153. Although no trend was observed, total-(α)-HBCD was only detected post-2000. Levels of the highest concentration brominated contaminant, BB153, showed no temporal change. As long-term ecosystem changes affecting contaminant levels may also affect contaminant patterns, we examined the influence of year (i.e., aging or “weathering” of the contaminant pattern), dietary tracers (carbon stable isotope ratios, fatty acid patterns) and biological (age/sex) group on congener/metabolite profiles. Patterns of PCBs, CHLs and PBDEs were correlated with dietary tracers and biological group, but only PCB and CHL patterns were correlated with year. DDT patterns were not associated with any explanatory variables, possibly related to local DDT sources. Contaminant pattern trends may be useful in distinguishing the possible role of ecological/diet changes on contaminant burdens from expected dynamics due to atmospheric sources and weathering.

Organochlorine Compounds and Their Metabolites in Seven Icelandic Seabird Species - a Comparative Study

The present study is designed to assess the occurrence of a few organochlorine contaminants and their metabolites in eggs of different marine bird species in Iceland, a country located in the sub-Arctic of the North-Western Atlantic. Previous investigations from e.g. Sweden and The Netherlands have shown some obvious differences in contaminant concentrations, including e.g. hydroxylated polychlorinated biphenyl metabolites (OH-PCBs) in guillemot (Uria aalge) and other bird species. Eggs from seven marine bird species, Arctic tern (Sterna paradisaea), common eider (Somateria mollissima), guillemot, fulmar (Fulmarus glacialis), great black-backed gull (Larus marinus), lesser black-backed gull (Larus fuscus), and great skua (Stercorarius skua), that all breed in Iceland, were collected and analyzed for several persistent organic compounds and their metabolites. The contaminant levels varied between the species investigated. The highest concentrations were found in eggs from the great skua (18 and 23 microg/g l.w. of CB-153 and 4,4'-DDE, respectively). The concentration difference was generally 2 orders of magnitude higher in great skua for all organochlorine compounds analyzed with the exception of HCB. HCB did not vary as much between the seven species (ranging from 34 to 710 ng/g l.w). OH-PCB and MeSO(2)-PCB metabolites congener concentrations and patterns showed differences in metabolic capacity between bird species. Guillemot and great skua seem to distinguish themselves most from other species i.e. with the absence of 4-OH-CB187 and low relative levels of 4-OH-CB146 in guillemot and the low abundance of OH-PCBs in great skua.

PCB 휨의 최소를 위한 더미 패턴의 최적 설계

In this work, a design method that minimizes PCB warpage is proposed. This work suggests that narrow dummy patterns are placed on the discetized location along the periphery of the PCB to control the warpage. The warpage is numerically simulated base on direct modeling of PCB patterns. The optimal pattern that minimizes warpage is determined using the human-based genetic algorithm.

PCB accumulation in osprey exposed to local sources in lake sediment

We examined the accumulation of PCBs in ospreys (Pandion haleaetus) that were exposed to local sediment sources. Eggs, chick plasma, and sediment samples were collected over a range of 14 km (0.2-14.2 km) from a PCB source in Sturgeon Lake, ON. Sum PCB concentrations declined in chick plasma (range 422.5-58.3 ng/g) as distance from the PCB source increased, but there was a poor relationship with sum PCBs in eggs. Both tissues indicated an Aroclor 1248/1254 source. Aroclor 1254 comprised an average of 66.9% of sum PCBs in chick plasma from Sturgeon Lake, but comprised only from 27.0 to 44.4% in plasma from other Great Lake colonies. Dietary differences among osprey colonies were not sufficient to explain the PCB patterns observed. There was weak evidence that the ability to metabolize PCBs may differ between juveniles and adults, based upon the PCB profile in eggs and chick plasma.

Tissue-specific congener composition of organohalogen and metabolite contaminants in East Greenland polar bears ( Ursus maritimus)

Congener patterns of the major organohalogen contaminant classes of PCBs, PBDEs and their metabolites and/or by-products (OH-PCBs, MeSO 2-PCBs, OH-PBDEs and MeO-PBDEs) were examined in adipose tissue, liver, brain and blood of East Greenland polar bears ( Ursus maritimus). PCB, OH-PCB, MeSO 2-PCB and PBDE congener patterns showed significant differences ( p ≤ 0.05) mainly in the liver and the brain relative to the adipose tissue and the blood. OH-PBDEs and MeO-PBDEs were not detected in the brain and liver, but had different patterns in blood versus the adipose tissue. Novel OH-polybrominated biphenyls (OH-PBBs), one tri- and two tetra-brominated OH-PBBs were detected in all tissues and blood. Congener pattern differences among tissues and blood are likely due to a combination of factors, e.g., biotransformation and retention in the liver, retention in the blood and blood–brain barrier transport. Our findings suggest that different congener pattern exposures to these classes of contaminants should be considered with respect to potential target tissue-specific effects in East Greenland polar bears.

Concentrations and possible sources of polychlorinated biphenyls in the soils of Hong Kong

A total of 66 surface (0–10 cm) soil samples covering the whole territory of Hong Kong were collected for analysis of the seven PCB congeners. The detectable concentrations of PCBs in the soils of Hong Kong ranged from 0.07 to 9.87 μg kg − 1 , with a higher concentration in the urban area than in the countryside. PCB patterns were dominated by the low chlorinated congeners. PCB118, a dioxin-like congener, was found in samples from Tsuen Wan and Sha Tin and was assumed to be deposited from local sources. Principal component analysis (PCA) revealed that the sources of PCBs were mainly associated with Aroclor 1242 and Aroclor 1248. A significant linear correlation between the concentrations of soil organic matter (SOM) and the sum of 7 PCBs and of SOM and PCB153 was observed. In total, PCBs were not a severe contamination in the soils of Hong Kong from the current results. However, long-term monitoring is still recommended to keeping, especially in the landfill deposits and some urban parks.

Environmental and occupational exposures and serum PCB concentrations and patterns among Mohawk men at Akwesasne

A study was conducted to address the question of how fish consumption, occupation, and outdoor air affected serum PCB concentrations and congener patterns among 139 Native American men living near three hazardous waste sites. They were interviewed about their residential, occupational, and dietary histories, and donated 20 ml of venous blood for congener-specific PCB analysis. The similarity in the congener pattern between that found in the serum and that detected in local environmental samples was measured by calculating the Euclidean distance between them. The results indicated that serum PCB concentrations were positively associated with cumulative lifetime exposures to PCBs from local fish consumption and occupation. However, participants who lived in the last 10 years at Raquette Point, which is the area of the Reserve closest to the hazardous waste sites and the only location where elevated levels of PCBs were found in outdoor air, did not have higher serum PCB concentrations than participants who lived elsewhere at Akwesasne. Regarding pattern matching, Mohawk men with the greatest cumulative lifetime exposure to PCBs from local fish consumption had a serum PCB congener pattern that more closely resembled that in fish caught off-shore from one of the hazardous waste sites than did men who ate less local fish. Similarly, Mohawk men who were occupationally exposed to PCBs were more likely than those without occupational exposure to have a serum PCB congener pattern that was similar to that of Aroclor 1248, the commercial PCB mixture used locally. The serum PCB congener pattern of Raquette Point residents more closely resembled the pattern in outdoor air only if the men ate relatively few local fish. The study is among the first to demonstrate that outdoor air may affect serum PCB congener patterns, at least in the absence of heavy fish consumption.

Identification of markers for PCB exposure in plasma from Swedish construction workers removing old elastic sealants

The objective of the present study was to identify PCB-indicators of occupational exposure related to the removal of old elastic sealants. Blood samples were collected from workers involved in removing elastic sealants. Samples were also taken from age- and sex-matched controls. A majority of the exposed workers were re-sampled after 10 months. All samples were analysed for 19 PCBs. The levels in the exposed workers were twice as high as those in the controls, 575 and 267 ng g(-1) lipid, respectively, but were essentially unchanged at the second sampling. The PCB patterns also differed. Levels of many less chlorinated PCBs were much higher in the exposed workers, compared to the controls, and principal component analysis (PCA) revealed that easily metabolized PCBs decreased in the exposed workers during the study. This finding indicates that elimination exceeded uptake during the study period, and that the safety information given to the workers had been effective. PCA was also used to identify exposure markers. The relatively persistent PCBs 56/60 and 66, the easily metabolized PCBs 44, 70 and 110 (with vicinal hydrogens in meta/para-positions) and the very persistent PCBs 153 and 180 were found to be good markers for occupational, recent occupational and background (dietary) exposure, respectively. A PCA model based on these markers was equally effective in differentiating between exposed individuals and controls, and between recent and less recent exposure, as a model based on all PCBs.

Bioaccumulation of PCBs in Arctic seabirds: influence of dietary exposure and congener biotransformation

Four seabird species and their prey (zooplankton or fish) were collected in the Barents Sea to determine how dietary exposure, cytochrome P450 (CYP) enzyme activities and sex influenced their hepatic PCB concentrations and accumulation patterns. Five males and five females from each seabird species (little auk ( Alle alle), Brünnich's guillemot ( Uria lomvia), black guillemot ( Cepphus grylle) and black-legged kittiwake ( Rissa tridactyla)) were analysed. PCB concentrations could not be explained directly by carbon source ( δ 13C) or trophic position ( δ 15N), but by a combination of dietary parameters ( δ 13C, δ 15N, migratory pattern, age) and contaminant metabolism. Contrary to previous studies, the PCB pattern differed among seabirds, with a higher proportion of persistent congeners (% of PCB-153, R PCB-153) in black-legged kittiwake than in auks. The PCB pattern also differed among auks, with little auk as the most efficient biotransformer (highest R PCB-153 values of persistent congeners). Based on high R PCB-153 values, Brünnich's guillemot poorly metabolised ortho– meta-unsubstituted congeners, whereas black guillemot poorly metabolised meta– para unsubstituted congeners. Species-specific differences in PCB biotransformation were confirmed by metabolic indices, where PCB patterns in seabirds were adjusted for PCB pattern in prey. The relative contribution of ortho– meta-unsubstituted congeners to ∑PCBsdecreased with increasing EROD activity. There were no differences in PCB concentrations, PCB patterns or cytochrome P450 enzyme activities between males and females. CYP P450 activities (CYP1A- and CYP2B/3A-like: EROD and testosterone 6β-hydroxylation, respectively) were low and did not correlate with concentrations of non- or mono- ortho Cl-substituted PCBs (NO- and MO-PCBs), or with total toxic equivalent concentrations (TEQs) for dioxin-like effects of NO- and MO-PCBs.

ＥＣＴ応用を目指したＳＶ−ＧＭＲセンサの高周波数微小磁界振幅特性

The eddy-current testing technique is an interesting method for detecting defects on bare printed circuit boards. This technique detects various defects without mechanical stress to PCB patterns. Usually various pickup coils are used in an ECT probe as a magnetic sensor. Pickup coil sensors, however, do not show enough S/N ratio to detect defects in high-density PCBs, whose conductors are less than 100μm. We propose a new ECT probe with a spin-valve giant magnetoresistive (SV-GMR) sensor for inspection of PCBs. SV-GMR sensors show high sensitivity to a small magnetic field in one direction. This sensor senses a magnetic field as varying its resistance unlike inductive sensors such as a pickup coil.In this paper, we investigated the sensing properties of a SV-GMR sensor with changing axes, frequencies, and magnetic field amplitudes, and discussed problems that could occur in replacing a pickup coil with SV-GMR.

PCB and PCDD/F totals, TEQs, and congener patterns in Korean coastal marine environments, 1987, 1988, 1990, and 1996-1999.

Various mussel and oyster samples and select top sediment samples were taken over 27 industrial and pristine coastal sites form South Korea's west, south, and east coasts. Site-specific total PCB, PCDD/F, and organochlorine TEQ levels in biota were 1-306 ng/g ww, 3-9,400 pg/g ww, and 0.3-200 pg/g ww, respectively. Temporal trends showed a general decrease in total TEQ with an increase in TEQ contribution by PCDD/Fs at most locations over the past decade. Linear regression was used to establish a relationship between each contaminant total and the respective TEQ contribution. Principal component analysis was used to model the congener-specific PCB and PCDD/F data, and two three-component models were developed that describe the congener-specific patterns based on the variance between samples over the entire data set. Unique PCDD/F patterns were identified and discussed with respect to outliers identified in the previously established TEQ regressions and a distinct PCDD/F pattern was found that related to a single industrial source (i.e., steel mill). PCB patterns were explored in relation to those of common commercial mixtures of PCBs (i.e., Aroclors) and patterns were discussed with respect to TEQ. It was found that sites with relatively high PCB-TEQs showed an Aroclor 1254-like contamination.

Source apportionment of polychlorinated biphenyls using compound specific isotope analysis

Reported here are results of the compound specific carbon isotopic analysis (CSIA) of individual PCB congeners. This investigation was designed to determine the suitability of CSIA on this class of compounds in natural materials. Samples of duck tissue, duck liver, duck egg and grass carp were collected from the Housatonic River, Massachusetts, and compared with samples of fresh Aroclor® 1242, 1254,1260, and 1262. Twenty congeners were selected for isotopic analysis based on their ability to be separated chromatographically and their expected abundance in tissue samples. Animal tissue samples showed variable PCB patterns and abundances although all animals were expected to have been exposed to Aroclor® 1260. These characteristics are thought to be related to the structure of the food web or metabolic and physiological features of the individual animals. Grass carp samples had excellent correlation in the isotopic compositions of the congeners. Although the correspondence of δ 13C in congeners from fresh Aroclor 1260 to congeners from tissue samples may not be expected to be identical, the patterns of similarity were very supportive of the maintenance of the isotopic signal into the food chain. The patterns observed in these and other samples suggest a fractionation process where residual congener pools can become progressively enriched while the congeners produced from degradation are more depleted. The isotopic patterns provide insight to degradation processes and into relative metabolic stability of the various congeners in different animals. The results of this study suggest that CSIA analysis of PCBs at natural abundance can provide significant insight into tracing these compounds through the natural environment. The data also suggest that tracking PCB mixtures may be possible using CSIA techniques after standard chromatographic matching or other fingerprinting techniques become blurred.

Ecotoxicological suitability of floodplain habitats in The Netherlands for the little owl ( Athene noctua vidalli)

This study describes the actual risks of exposure to contaminants, which little owls ( Athene noctua vidalli) face in Dutch river floodplains. The results indicate that PCBs pose a risk: not only are levels in little owls from floodplains higher than levels found in little owls from a reference site but the PCB patterns in owls from the floodplains also indicate induction of hepatic cytochrome P450 enzymes by dioxin like compounds, possibly PCBs. Of the heavy metals, only cadmium is thought to pose a risk in certain conditions, for example, when little owls are feeding only on earthworms over a prolonged period of time. The results do not indicate any effects on the occurrence of prey items of the little owl like for instance earthworm, beetles and shrews. Hence, it is not expected that little owls will be affected by diminishing prey availability due to contamination.

PCBs in dungeness crab reflect distinct source fingerprints among harbor/industrial sites in British Columbia.

Dungeness crab (Cancer magister) samples were collected from various pulp mill and principal harbor sites on the West Coast of Canada. Full congener PCB analysis was performed on several composite and single hepatopancreas samples from each site, and the spatial variability of PCB patterns was explored. A recently developed direct mixing model (DMM) which relies on iteration of representative Aroclor end-members was used to make source predictions based on congener-specific PCB data from biota. Additionally, factor analysis and principal component analysis (FA/PCA) were applied to examine the intersite variability for potential PCB-source patterns. This unsupervised exploratory analysis (i.e., FA/PCA) revealed three distinct clusters of variables containing either low (di-tetra), moderate (penta-hexa), and high (hepta-nona) levels of chlorination, which were related to common Aroclor mixtures (e.g., A1242, A1248, A1254, and A1260). Overall, the PCA scores for each site qualitatively agreed with the source predictions provided by the DMM, and distinct source compositions were predicted for various sites examined.

Historical Changes in PCB Patterns in Lake Ontario and Green Bay, Lake Michigan, 1971 to 1982, from Herring Gull Egg Monitoring Data

Patterns of PCB congener bioaccumulation were examined in archived herring gull ( Larus argentatus) eggs collected from Big Sister Island in Green Bay, Lake Michigan, and Scotch Bonnet Island in Lake Ontario from 1971 to 1982 as part of the Canadian Wildlife Service's Great Lakes Herring Gull Monitoring Program. Concentrations of 97 PCB congeners were measured. From 1971 to 1982, ecological half-lives of most congeners, particularly the tri- through hexachlorobiphenyls, were greater in eggs from Green Bay than Lake Ontario. Comparing sum PCB levels in eggs collected in 1971 and 1982, concentrations declined 80% at Scotch Bonnet Island and 74% at Big Sister Island. PCB congener patterns were different in eggs from the two colonies. Principal components analysis showed that inter-site differences in congener patterns became more apparent after 1976. This indicated that regional PCB sources were the most influential in determining patterns of biologically-available PCBs during the 1971 to 1982 period in these two lakes, via recycling of historical PCBs from sediments or gradually decreasing loading. Trend analysis of selected congeners specific to Aroclors 1242, 1254, and 1260 revealed that the rapid decline of less chlorinated congeners, observed from 1971 to 1976 in Lake Ontario, was explained by a decrease in loading of Aroclor 1242 to the lake. At both colonies, ecological half life of the congeners was significantly (p < 0.001) correlated with log K ow and with –log HLC. Changes in PCB composition, after 1976 in Lake Ontario and from 1971 to 1982 in Green Bay, could be explained by differences in the physical behavior of individual congeners affecting removal by volatilization and sedimentation.

光学特性を用いた印刷回路基板のパターン検査用照明装置の設計に関する研究

Automated Visual Inspection (AVI) capability has become an important key component in the automated manufacturing system. In such a visual inspection system an intensity image of a scene is quickly affected by optical property of objects, condition and roughness of surface, lens and filters, image sensor property and lighting system. In particular, the lighting system design is the most important factor, since it affects overall performance of the visual system. In this paper, the lighting subsystem of AVI system is analyzed for the inspection of PCB patterns. The reflection property is theoretically obtained by a reflection model and also obtained by experiments which measure intensity with varying the viewing direction of image sensor and the lighting direction of illuminator. The illumination uniformity of a ring-type illuminator is measured with varying the diameter of illuminator and the distance between object and illuminator. The lighting systems designed based upon the experimental results and theoretical analysis.