Automatic exposure compensation using an image segmentation method for single-image-based multi-exposure fusion

We have grown blue light-emitting diodes (LEDs) with low threading dislocation densities (TDDs) by using SiN interlayers on Si (111) substrates. Our growth technique using SiN layers makes it possible to decrease twist components (edge-type threading dislocation components). The edge-type TDDs are almost the same values as those of LEDs grown on Al₂O₃ (0001) substrates. EQE of LEDs grown on Si (111) substrates increases with decreasing edge-type dislocation in the low-current-density region, and the EQE of the sample with low TDD is almost as high as that of the LED grown on an Al₂O₃ (0001) substrate at room temperature. It is found that the hot/cold factors (HCFs) of LEDs grown on Si (111) substrates increase with decreasing edge-type dislocations in the low-current-density region, but are less than those of an LED grown on an Al₂O₃ (0001) substrate. Time-resolved photoluminescence (TRPL) shows that the dominant origin of the thermal quenching is edge-type dislocations in our samples, but other defects such as screw-type dislocations also contribute to it. We also found the fluctuated emission patterns consisting of bright and dark areas originated from the difference of Shockley–Read–Hall (SRH) type defect densities in the multi-quantum wells (MQWs) grown on Si (111) substrates. The bright areas spread, and the configurations of the bright areas change into ring-like patterns with reducing edge-type TDDs. We suggest that the internal quantum efficiency (IQE) of dark areas should be promoted to improve the performance of the MQWs grown on Si (111) substrates.

The Martian Surface

Observations of apparent frost phenomena, occurring preferentially in the Martian bright areas, have in the past led to the conclusion that the bright areas are elevations. The argument hinges on the implicit assumption that, near midday, highlands should be at lower temperatures than lowlands. On the earth, this assumption is valid, because of adiabatic cooling of rising air, a diminished greenhouse effect, and a greater inclination of surfaces to the sun's rays for highlands than for lowlands. It is shown that these factors are unlikely to be important on Mars and that the polar cap recession data, in particular, suggests that the dark areas are highlands. From the radar Doppler spectra, it is found that the Martian dark areas tend to have higher elevations than the adjacent bright areas. Slopes of a few degrees are deduced, and peak elevation differences between 4 and 17 km are inferred. These results may bear on the discrepancies between ground-based spectrometric values and Mariner 4 occultation values of Martian surface pressure and on the discrepancies between the optical and the dynamical oblateness of Mars. They suggest that pressures ∼20 mb are typical of the centers of bright areas, and 6 mb is a typical dark area pressure.

In this paper, we have investigated the scan mura due to the difference of spacer position in each nozzle of inkjet heads for inkjet spacer process. It was found that the difference of the cell gap was about 0.051 µm between a bright area and a dark area in panel with strong scan mura. The difference of the cell gap means the subtracted value of the cell gap in the dark area from the cell gap in the bright area. In the case of adjusting of dropped ink velocity on each nozzle, the scan mura is improved, but is not perfect. On the other hand, the scan mura is drastically improved by the randomization of spacer position using nozzle mixing method (NMM), where the difference of cell gap is only 0.009 µm. It is considered that the scan mura is strongly influenced by ink dropped position, the inkjet process.

In recent years, the use of computerized tomography (CT) to characterize two-phase fluid flow through porous media has become increasingly popular. This paper describes a different application of CT: it use as a core analysis tool. The advantages and disadvantages of the different technological generations of commercial medical CT scanners available as core analysis instruments are also discussed. Additionally, methods are presented for improving images and reducing CT-number errors inherent in the scanning of high-density rock samples on instruments whose software was designed for the scanning of the low-density human patients.

We present adaptive optics data from the Keck telescope, taken while the Huygens probe descended through Titan's atmosphere and on the days following touchdown. No probe entry signal was detected. Our observations span a solar phase angle range from 0.05° up to 0.8°, with the Sun in the west. Contrary to expectations, the east side of Titan's stratosphere was usually brightest. Compiling images obtained with Keck and Gemini over the past few years reveals that the east‐west asymmetry can be explained by a combination of the solar phase angle effect and an enhancement in the haze density on Titan's morning hemisphere. While stratospheric haze was prominent over the northern hemisphere, tropospheric haze dominated the south, from the south pole up to latitudes of ∼45°S. At 2.1 μm this haze forms a polar cap, while at 1.22 μm it appears in the form of a collar at 60°S. A few small clouds were usually present near the south pole, at altitudes of 30–40 km. Our narrowband J,H,K images of Titan's surface compare extremely well with that obtained by Cassini ISS, down to the small‐scale features. The surface contrast between dark and bright areas may be larger at 2 μm than at 1.6 and 1.3 μm, which would imply that the dark areas may be covered by a coarser‐grained frost than the bright regions and/or that there is additional 2 μm absorption there.

The light curve of Pluto is analyzed in terms of a geometrical model consisting of bright and dark areas which are assumed to exhibit either a diffuse or a geometrical type of reflectivity. A Fourier analysis method is used to invert the observed light curve to obtain the longitudinal distribution of bright and dark areas for any combination of albedos selected for the two types of terrain. The analysis indicates that the light curve of Pluto can be readily understood in terms of a surface consisting of bright and dark areas. However, on the basis of the presently available photometric data, the existence or absence of limb-darkened material cannot be established.

Haze scatters light transmitted in the air and reduces image quality, which greatly decreases the interpretability and intelligibility of an image. To solve these problems, we propose an improved real-time image dehazing algorithm based on dark channel prior and fast weighted guided filtering. First, the image is divided into dark areas and bright areas by the K-means clustering algorithm, and the atmospheric light value is calculated according to the proportion of the bright area in the whole image. Second, the fast weighted guided filtering algorithm is employed to generate a refined transmission map, which removes the halo artifact from around the sharp edges. Finally, the gamma correction and automatic contrast enhancement algorithms are used to adjust the brightness and contrast of the dehazing image. Experimental results demonstrate that the proposed method can effectively remove the halo artifacts, improve the color deviation, and retain more details in the images.

Structure of the carbon layer deposited on the steel surface after low pressure carburizing

Demarcation of nonmelanoma skin cancer margins in thick excisions using multispectral polarized light imaging.

This paper is an analysis of radar observations of Mars, particularly at 12.5-cm wavelength, performed at the Goldstone facility of the Jet Propulsion Laboratory, during the 1965 opposition. Then the entire range of Martian longitudes at north latitude 21?6 was observed with an effective topographical resolution in the quasi-specular component of some 6 planetocentric degrees. Both for the 1963 and for the 1965 oppositions a very striking correlation is noted between high reflectivity at radar frequencies, and dark areas at optical frequencies. The correlation applies to the central longitude of the Martian features, to the extent of the features, and to their relative reflectivity rankings at the two frequencies. Despite these correlations, there are occasional displacements between the reflectivity maxima and the centers of dark areas of the order of 10 . This is greater than the expected errors in Martian cartography and in the location of the radar sub- terrestrial point on Mars. For example, Syrtis Major appears as a radar reflectivity relative minimum, while the 10 longitude strips east and west of Syrtis Major appear as relative maxima. Such observations can be explained-while retaining the hypothesis that the Martian dark areas are intrinsically more reflective at microwave frequencies-if the dark areas have slopes of several degrees. On this basis alone the dark areas might be either elevations or depressions. Conditions on slopes can also be set for those cases in which strong radar reflection comes from a bright area adjacent to a dark area. In this case, a dark area must have an appropriate two-dimensional alignment (in the plane of the sky) with respect to the radar station. From the fact that only the near sides of elevations, but the far sides of depressions, are suitably oriented for specular backscattering, the comparative alignments of near and far sides make it unlikely that dark areas are depressions, a conclusion also supported by other radar evidence. The hypothesis that the dark areas are elevations is systematically examined in the 36 Doppler spectrograms of the 1965 opposition, and is found to be consistent with these data. The radar data suggest that the dark areas examined in the 1965 opposition were generally not truncated, but rather sloped gently downward from the center of the dark area scanned. From this fact elevations can be deduced from slopes. It is found that some regions that characteristically undergo marked secular changes have very shallow slopes (t-2 ) and elevations 6 km; classical canals have steeper slopes (>4 ) but elevations of the same order; and large dark areas such as Syrtis Major and Moeris Lacus may have elevations between 10 and 20 km. These elevations and slopes are inconsistent neither with optical searches for elevations at the limb, nor with the yield and tensile strengths of ordinary solids under the reduced gravitational acceleration of Mars. The general picture of Mars that emerges is simi- lar to that expected for the earth, were the oceans removed, the effects of water erosion eliminated, and the relief enhanced by the ratio of the gravitational accelerations on the two planets. The dark areas are similar to continental blocks and the bright areas to dry ocean basins. This conclusion bears adversely on those theories of continental origins that depend on the existence of a liquid planetary core.

In this work, we discuss a new fundamental PID mechanism that has not been reported. We developed in-situ Kelvin probe force microscopy to monitor the potential evolution at nanometer scale under high-voltage stress. We observed large-area junction degradation during the stressing and junction recovery by heat treatment from the same location. Electron-beam induced current (EBIC) results support the large-area damage, which has a much lower collected current (dark region) and has an abrupt transition between the bright and dark areas, in addition to local shunts. Transmission electron microscopy does not find stacking faults in the dark-EBIC region. Furthermore, time-of-flight secondary-ion mass spectrometry indicates that the large-area damage correlates with more sodium content. The consistent results shed new light on PID mechanisms that are essentially different from the widely reported local-junction shunts.

By using slit observations of solar photospheric lines shifted by 0.4 arcsec, a 2D field on the Sun was scanned to obtain a 16-minute time series of 2D line-parameter variations. The aim was to investigate in detail the occurrence of turbulence that can be measured by line-width variations extracted from the line profiles. The continuum-intensity variation served as a proxy for granular (bright) and intergranular (dark) areas. The results show that turbulence is not limited to the intergranular space but is also produced by horizontal motions that may become supersonic, leading to turbulence. These motions lead to brightenings, as predicted by theoretical models. Thus, enhanced line-width variations are found to occur in both bright and dark areas. A Sobel filter served to detect the areas where strong gradients in the line parameters occur. By applying this filter to the different line-parameter variations over the 2D field observed, we can determine whether there exists a similarity of these strong-gradient patterns with other parameters that characterize granular motions such as intensity variations or velocity fluctuations.

Backscattered electron (BSE) imaging of scanning electron microscopy (SEM) was applied to a study on the mineral density of the bone surface. The neonatal and adult mouse parietal bones freed of the periosteum and covering cells were examined in a field emission scanning electron microscope equipped with a high sensitivity BSE detector at 1-30 kV accelerating voltages. The mineral density of the bone surface was observable in BSE images at 5 kV accelerating voltage while only the topographic structures of the surface were obtained under an accelerating voltage less than 5 kV. As the accelerating voltages increased from 5 kV, the bright areas were extended, probably due to the imaging of the calcified bone matrix under the uncalcified osteoid. The bone surface is usually divided into smooth and rough areas according to its irregularities. BSE images at 5 kV clearly showed that the smooth areas were further divided into dark and bright areas which apparently corresponded to the uncalcified osteoid and calcified bone matrix, respectively. Bright granules, about 1.0-3.0 microns in diameter, were sometimes observed at the border between the osteoid and calcified bone matrix; these granular calcified areas were regarded as the calcifying front forming the calcified bone matrix from the osteoid. The present study demonstrated that the distribution of the osteoid on the mouse parietal bone surface changes depending on age: the osteoid occupied a large area in the parietal bone surface in neonatal mice, but was small in adult mice. Thus, low accelerating voltage SEM using BSE provides new information on the distribution of the osteoid and the bone matrix calcification under both normal and pathological conditions.

This paper describes an efficient image enhancement method based on the multi-scale retinex (MSR) theory for applying to a motion picture pre-processing. The proposed method uses a multi-rate x-y separable Gaussian filter with a polyphase structure and conducts illumination domain MSR composition. Therefore, The processing amount is drastically reduced to 4-order less than that of original MSR. As enhancing dark and bright areas in an image is the main pre-processing purpose, the method modifies an enhancement function so as to improve color rendition of bright areas on an image. Although our approach aims at simple implementation, the proposed method shows similar performance to the original one and better performance than those of histogram equalization approaches.