Using digital anaglyphy to improve the relief effect of SEM micrographs of bloodstains

Three-dimensional surface reconstruction and in situ site-specific cutting of the teliospores of Puccinia miscanthi causing leaf rust of the biomass plant Miscanthus sinensis

The rust fungus Puccinia miscanthi on the naturally infected leaves of eulalia grass were investigated by light and electron microscopy. Many black telia were present on both the adaxial and abaxial leaf surfaces. The telia were often confluent, protruding distinctly from the leaf surface, and had numerous teliospores. Light microscopy revealed that the teliospores were club-like in shape (clavate), chestnut brown, and produced pedicels from one end. They were measured to be approximately 45 μm × 20 μm in size, and slightly constricted at the septa. Using stereo imaging, it was possible to generate images with more three-dimensionality than conventional scanning electron micrographs. Without the need for the mechanical sectioning of telia, the height of telia from the leaf epidermis could be measured at approximately 230 μm using three-dimensional surface reconstruction. Urediniospores were also found on the leaf surface, and possessed spines on the surface (echinulate). The internal features of the nonembedded teliospores could be unveiled using a focused ion beam system with a field emission scanning electron microscope, allowing for the in situ site-specific cutting of the non-embedded teliospores. These results show that three-dimensional surface reconstruction and targeted cutting are a potential alternative to mechanical sectioning of resin-embedded blocks, and have the potential to eliminate the uncertainty involved in selecting the region of interest.

Stereophotography and spatial surface reconstruction using scanning electron microscopy images

Three-dimensional reconstruction technique to fully characterize structural performance of solid materials is suggested. The three-dimensional sample data out of the SEM images taken from different angles were extrapolated, measured and interpreted. In stereometry, the technique of three dimensional SEM imaging is fairly straightforward. Selected specimen area is photographed using SEM imaging tools from two different angles. Tilting is performed using standard SEM manipulation tools. In some cases, the specimen must be rotated to such a position, in which the tilting is done on visual ordinate axis. The resulting images are combined in pairs using any three-dimensional anaglyph software available to produce an anaglyph image, which, in turn, can be analyzed using standard 3D glasses. To achieve finer results, extrapolation of spatial data was done from three or more sample images using visual reconstruction software applications. This technique for recovering spatial data from the SEM pictures (structure-from-motion) is the VisualSFM software, which is an application for spatial reconstruction using structure from sample motion. Using VisualSFM, the images are analyzed for matching points and the camera angle is guessed for each image. Any number of additional viewports can be added to VisualSFM software. Based on this input, a surface is reconstructed where the matching points intersect and a colour value is assigned. The software produces a cloud of points, which has to be processed externally. Freely available software, such as MeshLab can be used to join the point cloud to a mesh and, as a second step of reconstruction, apply surface properties to the mesh polygons. The gold particles were selected as model material for the spatial 3D surface reconstruction.

Using digital colour to increase the realistic appearance of SEM micrographs of bloodstains

Although in the scientific-research literature the micrographs from scanning electron microscopes (SEMs) are usually displayed in greyscale, the potential of colour resources provided by the SEM-coupled image-acquiring systems and, subsidiarily, by image-manipulation free softwares deserves be explored as a tool for colouring SEM micrographs of bloodstains. After acquiring greyscale SEM micrographs of a (dark red to the naked eye) human blood smear on grey chert, they were manually obtained in red tone using both the SEM-coupled image-acquiring system and an image-manipulation free software, as well as they were automatically generated in thermal tone using the SEM-coupled system. Red images obtained by the SEM-coupled system demonstrated lower visual-discrimination capability than the other coloured images, whereas those in red generated by the free software rendered better magnitude of scopic information than the red images generated by the SEM-coupled system. Thermal-tone images, although were further from the real sample colour than the red ones, not only increased their realistic appearance over the greyscale images, but also yielded the best visual-discrimination capability among all the coloured SEM micrographs, and fairly enhanced the relief effect of the SEM micrographs over both the greyscale and the red images. The application of digital colour by means of the facilities provided by an SEM-coupled image-acquiring system or, when required, by an image-manipulation free software provides a user-friendly, quick and inexpensive way of obtaining coloured SEM micrographs of bloodstains, avoiding to do sophisticated, time-consuming colouring procedures. Although this work was focused on bloodstains, well probably other monochromatic or quasi-monochromatic samples are also susceptible of increasing their realistic appearance by colouring them using the simple methods utilized in this study.