Thermo Fisher Velox saves every STEM and TEM acquisition as an .emd file: an HDF5 container
with one dataset per detector, the camera frames, EDS spectra and, for spectrum images, the raw
stream of X-ray events. Without Velox, the pictures, their calibration and the spectra are hard
to get at. This page turns the file into ordinary TIFF, PNG and CSV files.
How to convert EMD to TIFF
- Upload one or more
.emdfiles, or a.zipof a whole session. - Choose PNG or JPEG for the pictures, the corner and colour of the scale bar, and whether frame series become one averaged picture, the first frame or a picture per frame.
- Download a TIFF and a picture for every detector (HAADF, DF, BF, DPC, camera), named after the file and the detector.
What is kept
- Calibration. Each TIFF carries the pixel size and unit in the form ImageJ and Fiji read, so Analyze, Set Scale shows nanometres straight away. Diffraction patterns are calibrated in 1/nm.
- Values. 8 and 16-bit data stay as recorded; other types are saved as 32-bit float. Drift-corrected frames and image series become one multi-page TIFF.
- Complex images. FFTs are shown as their log magnitude and DPC vector images as a colour wheel picture.
- EDS. Spectra are written as CSV with one column per detector and their sum. For spectrum images you also get the sum spectrum, a total-counts map, a map for each element selected in Velox (or the ones you type), a colour overlay and the maps Velox itself saved.
- Settings. Accelerating voltage, magnification, detector, dwell time, camera length, stage position and every other stored entry, as text and JSON.
Things to watch
- Velox can save spectrum images as "reduced data", without the X-ray event stream. Their pictures, stored maps and spectra are converted, but per-pixel spectra cannot be rebuilt.
- The picture uses an automatic contrast stretch; the TIFF always holds the original numbers, so measure intensities on the TIFF, not on the PNG.
- Test files span Velox format versions 4 to 13, from single images to EDS and EELS spectrum images.
For Gatan files see DM3 and DM4 to TIFF; for EDS maps from Bruker Esprit see Bruker BCF files.
More about what this tool reads and writes: Electron Microscopy File Converter (EMD, DM3, DM4, SER, TIFF).