MLx Home | Contents | MLx menu | MLx buttons | Widgets | Index | What's New | Multivariate Button
These sets of images are small (64x64) quantitated (JEOL) electron probe maps of ceramic superconductor precursor material. The material has several distinct phases which are seen in the maps, and more clearly seen in color overlays and scatter diagrams.
The lines on top of the list are output of the image load ing function listing the images. The list of images has the
Selecting all of the images in the dialog (upon invoking the limits command) and then clicking on the Monitor Window (and perhaps scrolling it) gives this printout.
Note that the printout is in a text window, and could have been cut and pasted to this HTML file as text rather than as an image, but I wished to show exactly what the printout looks like.
Note, for later processing, that all of the images go to zero somewhere, and that all of them have values greater than 255, so that they must be scaled to be displayed.
The file names are printed in this list just as they are in the dimensions list above.
Viewing the Images
Here are a couple of convenient ways to view the images. The small version keeps the original size, the large one, for larger screens, zooms the images.
Immediately after tiling, none of the images is in front, so all of the title bars are white.
|If the images above are clicked on, left to right, in turn and then tiled again, their order is reversed. They are tiled in 'reverse' click order, ie. last clicked first, as this image is in front.|
|Note that the images are not large enough to read the entire titles, but enough is visible to identify each image.|
Color Overlay (also see Kowala example)
Although the regions of different phases (compositions) can be determined by examining the images separately, RGB color overlays make the regions stand out at a glance (Bright 1990, 1991)
The upper left part of the Multivariate Buttons window will then look like this. The image names replace the original button names.
The RGB overlay requires three gray level images of the same dimensions (but not necessarily of the same pixel type or intensity range. The overlay is made from the scaled images, which are always unsigned 8-bit images.) After selecting one image, only those images of the same size as the other two will be presented for selection.
This overlay was zoomed by x1.5 using the zoom menu in order to make it the same size as the others.
There appear to be four phases present.
Another way to see how many phases there are, and quantify them as well, is to use scatter diagrams (see introduction). Using the three images already selected for the color overlay (also see Kowala example)
To see what regions of the images correspond to the features of this scatter diagram, see traceback 1.
The traceback command makes a color labeled image (a traceback map) corresponding to the original images. The color for any pixel is the (automatically assigned) color of the parallelogram shaped region that encloses the corresponding point in the scatter diagram.
Note: when making the parallelograms, you may drag off the image. That is ok. Regions outside the image are ignored.
After closing the pink info line, the traceback mask (zoomed here) will appear.
Note how the regions (but of course not the colors) roughly correspond to the pastel colored regions in the color overlay.
|This is a 'palette' window. It labels the colors of the parallelograms in the scatter diagram and the colored regions in the mask. Option-clicking a color or a label allows you to change it.|
Traceback for the three-dimensional scatter diagrams is identical to that of the two dimensional diagrams. Regions are selected by 'mousing' parallelograms. The selected points appear inside the parallelogram -- physically, they are in a parallelopiped seen end-on. I have not implemented graphics to show side views of the selection region by rotating the scatter diagram. Once the diagram is rotated, the selection regions are not valid.
Try different views of the 3-D scatter diagram to make sure that unwanted bins are not selected because they are along the line of sight of desired bins.
The data were taken by Ryna B. Marinenko, NIST, Gaithersburg, Md. and by Slavko Bernik, currently at the Jozef Stefan Institute, Ljubljana, Slovenia. (see references by Marinenko and Bernik)
The pixel values are weight percent x 100 (the images are 16 bit integers), except for the total map which is percent x 10.
Sets 1 and 2 - mixed phases .Set 3 - appears to have only one phase - the desired superconducting phase, The broadening of the ratio of (Bi+Pb)/(Sr+Ca) is probably due to self shielding in the e-probe.
D. S. Bright, R. B. Marinenko, S. Bernik "Identification of Multiphase Systems Using Compositional X-ray Maps", pp. 203-4 in MICROBEAM ANALYSIS, Proceedings of the 28th Annual MAS Meeting, John J. Friel ed., VCH NY, NY. 1994
Marinenko, R.B., Bright, D.S. and Bernik, S. (1996) "Multiphase Analysis of Bi-Sr-Ca-Cu-O High Tc Superconductors with X-Ray Compositional Mapping", SCANNING (18): 395-400
D.S.Bright (1990),"SOFTWARE TOOLS FOR EXAMINATION OF MICROANALYTICAL IMAGES", Microbeam Analysis 1990:73-78.
Bright, D.S. and Newbury, D.E. (1991) "Concentration Histogram Imaging", Analytical Chemistry 63(4):243A-250A, (Feb. 15) 1991