Resolution Charge Coupled Device Camera Research Articles

Automated geometric correction of multispectral images from High Resolution CCD Camera (HRCC) on-board CBERS-2 and CBERS-2B

China–Brazil Earth Resource Satellite (CBERS) imagery is identified as one of the potential data sources for monitoring Earth surface dynamics in the event of a Landsat data gap. Currently available multispectral images from the High Resolution CCD (Charge Coupled Device) Camera (HRCC) on-board CBERS satellites (CBERS-2 and CBERS-2B) are not precisely geo-referenced and orthorectified. The geometric accuracy of the HRCC multispectral image product is found to be within 2–11km. The use of CBERS-HRCC multispectral images to monitor Earth surface dynamics therefore necessitates accurate geometric correction of these images. This paper presents an automated method for geo-referencing and orthorectifying the multispectral images from the HRCC imager on-board CBERS satellites. Landsat Thematic Mapper (TM) Level 1T (L1T) imagery provided by the U.S. Geological Survey (USGS) is employed as reference for geometric correction. The proposed method introduces geometric distortions in the reference image prior to registering it with the CBERS-HRCC image. The performance of the geometric correction method was quantitatively evaluated using a total of 100images acquired over the Andes Mountains and the Amazon rainforest, two areas in South America representing vastly different landscapes. The geometrically corrected HRCC images have an average geometric accuracy of 17.04m (CBERS-2) and 16.34m (CBERS-2B). While the applicability of the method for attaining sub-pixel geometric accuracy is demonstrated here using selected images, it has potential for accurate geometric correction of the entire archive of CBERS-HRCC multispectral images.

MOIRÉ INTERFEROMÉTRICO APLICADO AO ESTUDO DA ARQUITETURA DE PLANTAS

Plant architecture research subjects are of significant importance to genetics, photosynthesis, tran-spiration, crop-machine mechanical relationship, etc. In this sense, this research work had been carried in developing a new technique to generate the three dimensional view of plant shape. In this work the plant architecture determination will be carried out by means of a phase shift moiré method. The importance of the proposed method is based on the application of a sequence of four grids out of phase by an angle of π/2 radians one from each other. A digital camera was employed to capture the moiré patterns, which will generate the image to be processed. The procedure of image analysis involved softwares as Microsoft Powerpoint, Coreldraw and Idrisi. The use of a highly continuous sinusoidal grid, of a collimated light beam, of a higher resolution Charge Coupled Device Camera, as well as the superposition of image discontinuities during the unwrapping pro-cedure included in the phase shifting method, avoided noise occurrence satisfactorily, improving image quality.The conception of tests leading to height determination to generate a topographic description of a plant model was conceived based on optical moiré techniques. Obtained results reveal a great potential of the proposed method in determining plant architecture with high preci-sion, at low cost and being not time demanding.

Quantitative microtomography of ultrastructure in bones with 1 μm volumetric resolution (abstract)

Refractive and diffractive artifacts can dominate the spatial resolution and affect quantitative measurements by microtomography at the micron level. We have recently developed x-ray computed tomography methods that demonstrated 1 μm resolution in three dimension in the final reconstruction. The first method used a Fresnel zone plate to produce a submicron focal spot which was then rastered across the sample see W. Yun et al., Rev. Sci. Instrum. 70, 2238 (1999). The second method used a collimated beam and a high resolution charge coupled device camera to capture the absorption image of the sample in close proximity see A. Koch et al., J. Opt. Soc. Am. A 15, 1940 (1998). Both methods were applied to study the mineral ultrastructure of individual trabeculae. Using volumetric viewing, the volume, shape, and orientation of osteocyte lacunae and major cannaliculae can be observed. Quantitative measurements and comparison between the two methods will be presented.

Interpretation of capillary generated spatial and angular distributions of x rays: Theoretical modeling and experimental verification using the European Synchrotron Radiation Facility Optical beam line

Using a detailed ray-tracing code for capillary optics, interpretation is given for parallel bore hole and tapered capillary generated far-field images. These images can be used to indicate the presence of various types of surface imperfections (i.e., surface roughness or waviness) or shape distortions of the optical device. The capillary output patterns were recorded at the optical beam line of the European Synchrotron Radiation Facility by using a monochromatic, highly parallel incident synchrotron beam. Capillaries of various dimensions were studied, with inlet diameters in the range of 30–70 μm, outlet diameters of 22–42 μm, and capillary length values ranging from 10 to 23 cm. The far-field images were taken at a distance of 10–11 cm from the capillary exit using a high resolution charge coupled device camera. By comparisons of simulated and experimental capillary output patterns, the effects of surface roughness/waviness, as well as axial distortions are studied with respect to the angular distribution of the generated capillary beam.