Graphics mini manual

The computer graphics capabilities available at the Center are introduced and their use is explained. More specifically, the manual identifies and describes the various graphics software and hardware components, details the interfaces between these components, and provides information concerning the use of these components at LaRC

Identification of Terrestrial Reflectance From Remote Sensing

Correcting for atmospheric effects is an essential part of surface-reflectance recovery from radiance measurements. Model-based atmospheric correction techniques enable an accurate identification and classification of terrestrial reflectances from multi-spectral imagery. Successful and efficient removal of atmospheric effects from remote-sensing data is a key factor in the success of Earth observation missions. This report assesses the performance, robustness and sensitivity of two atmospheric-correction and reflectance-recovery techniques as part of an end-to-end simulation of hyper-spectral acquisition, identification and classification

Gray matter heterogeneity in Asperger syndrome assessed by MR texture analysis and its impact on regional gray matter volume

Brain imaging studies contribute to the neurobiological understanding of Autism Spectrum Conditions (ASC). Herein, we tested the prediction that distributed neurodevelopmental abnormalities in brain development impact on the homogeneity of brain tissue measured using texture analysis (TA; a morphological method for surface pattern characterization). TA was applied to structural magnetic resonance brain scans of 54 adult participants (24 with Asperger syndrome (AS) and 30 controls). Measures of mean gray-level intensity, entropy and uniformity were extracted from gray matter images at fine, medium and coarse textures. Comparisons between AS and controls identified higher entropy and lower uniformity across textures in the AS group. Data reduction of texture parameters revealed three orthogonal principal components. These were used as regressors-of-interest in a voxelbased morphometry analysis that explored the relationship between surface texture variations and regional gray matter volume. Across the AS but not control group, measures of entropy and uniformity were related to the volume of the caudate nuclei, whereas mean gray-level was related to the size of the cerebellar vermis. Similar to neuropathological studies, our study provides evidence for distributed abnormalities in the structural integrity of gray matter in adults with ASC, in particular within corticostriatal and corticocerebellar networks. Additionally, this in-vivo technique may be more sensitive to fine microstructural organization than other more traditional magnetic resonance approaches and serves as a future testable biomarker in AS and other neurodevelopmental disorders