Anaglyph Images Research Articles

Trabecular rod buckling index in thoraco-lumbar vertebral bone†

The need for improved mechanistic understanding of cancellous bone failure is at the core of important clinical problems such as osteoporosis, as well as basic biological issues such as bone formation and adaptation. Three-dimensional (3D) anaglyphs were produced from 15 T12 and L1 vertebral bodies, which encompass the adult life span in both sexes. The anaglyphs were viewed with red-green stereo glasses, using an image analyzer, and trabecular thickness and trabecular length were measured. From biomechanical principles, the strength of individual trabeculae can be estimated from measurement of trabecular rod thickness and trabecular rod length as the load to buckling index. The distribution of the load to buckling index was best described by a log normal curve. Trabecular rod thickness, trabecular rod length, and load to buckling index for males were consistently greater than for females. With aging, trabecular rod thickness, and the load to buckling index decrease for males while trabecular rod length increases for females. In this study, the load to buckling index for thoraco-lumbar vertebral trabecular rods potentially quantifies a greater risk of vertebral fracture for females. Decreased trabecular rod thickness or increased trabecular rod length result in the strength of trabeculae shifting closer to a putative fracture threshold. The corollary being that there is a reduced safety margin for resistance to mechanical loads for the vertebral bodies. The 3D anaglyph technique for measuring trabecular dimensions provides an accurate and precise methodology by which these morphological studies can be undertaken.

Trabecular rod thickness by direct measurement from 3D SEM anaglyphs.

This study presents a methodology for measuring the thickness of trabecular rods directly from anaglyphs. Macerated sagittal slices of T12 vertebral bodies from 15 subjects were examined by scanning electron microscopy (SEM). Two digital images (the second image tilted 5 degrees ) were recorded, and a 3D anaglyph was created. The thickness of the trabecular rods (Tb.Th((rods))), and the anatomical orientation of the trabecular rods were measured using an image analyser. Conventional 2D histomorphometry was performed on adjacent bone slices. A total of 1559 rod measurements were made from the 15 vertebral bone slices, with a mean Tb.Th((rods)) of 123 +/- 36 microm. The rod thickness in males (128 +/- 34 microm) was significantly greater than that in females (119 +/- 37 microm, P < 0.001). Tb.Th((rods)) changed significantly with age in the males: the thicker rods in the younger men reduced with age to a thickness similar to that in women. 3D measurements were significantly larger than the 2D estimates, and there was no correlation between the two methods of measurement. An inverse correlation was found between the number of rods and the bone volume fraction (BV/TV), indicating that decreased BV/TV is associated with an increased number of rods. The vertical rods (132 +/- 39 microm) were significantly thicker than the horizontal rods (116 +/- 33 microm, P < 0.001). The determination of rod numbers, and their orientation and individual thicknesses enables a greater understanding of cancellous bone architecture in both individuals and populations, and will allow more reliable finite element modelling. Direct measurements from 3D anaglyphs of intact specimens provide new data that show previously unrecognised age- and sex-related changes.

DIRTCam in the desert: The Silver Lake field test of the Robotic Arm Camera

The Robotic Arm Camera (RAC) is a panchromatic imager included as part of the Mars Volatiles and Climate Surveyor (MVACS) science experiment on Mars Polar Lander and on the Mars 2001 lander. It is designed to take both panoramic and microscopic images in order to gather data on the morphology and mineralogy of surface materials. In order to demonstrate these capabilities, a field test was conducted at Silver Lake playa in the Mojave Desert. The test consisted of going to a remote site unknown to the science team and providing that team with a data set of RAC panoramic, anaglyph, and microscopic images similar to what would be available during an actual landing. With only this information the science team attempted a determination of the position and the geology of the field test site. Using panoramic and anaglyph images provided by RAC, in conjunction with overflight images simulating data from a descent camera, the landing site for the field test was determined within 50 m of the actual site as lying near both a playa and an alluvial fan. Images of samples from the surface and within the trench revealed grain morphology, texture, and mineralogy indicating a soil dominated by quartz and feldspar, interspersed with a minor mafic component. Grain‐size distribution was bimodal, with small, rounded to subrounded grains dominant at lower depths and larger, more angular grains more plentiful near the surface. This mineralogy is confirmed by the geology of the site and the data provided by the descent images and mid‐IR measurements. RAC has demonstrated its ability to image the local geology and identify the major mineralogic components of an unknown site. These abilities will be crucial in understanding both the macroscopic and the microscopic geology of future Mars landing sites. This test also has demonstrated the crucial link between RAC data and complementary data sets such as context images and compositional data that can support the mineralogic observations made by RAC.

Low Cost 3-D Viewing of Chemical Structures

This paper discusses the procedures used to generate the anaglyphic images of chemical structures with molecular modeling programs and desktop image processing software (such as Adobe Photoshop). The approach provides a low-cost delivery system for stereoscopic molecular viewing.