Jovian LabsSEM scale bar & pixel-size check
Drop a folder of SEM or TEM images: the page reads the pixel size stored by Zeiss and Thermo Fisher (FEI) microscopes, finds and measures the scale bar in the data band, cross-checks the two, flags mixed magnifications and lets you download each image with a clean scale bar. Free, and your images never leave your computer.
Drop images here or
TIFF (8 or 16 bit, uncompressed, LZW or Deflate), PNG, JPG. Original TIFF files keep their calibration.
| Image | Size (px) | Metadata | Scale bar | From bar | Field of view | Check | Clean bar |
|---|
✓ consistent (metadata and bar within 1 %) · ! check (1 to 3 %, or bar length missing) · ✗ problem (over 3 %, or no calibration). The PNG button exports the image without the data band and with a clean, round-length scale bar.
Calibrated images can go straight into the particle size & nanomaterial screening, porosity or fiber diameter tools, which use the same calibration logic.
Questions
Where is the pixel size stored in a Zeiss SEM TIFF?
In the private TIFF tag 34118 (CZ_SEM), a text block written by SmartSEM: the line AP_IMAGE_PIXEL_SIZE is followed by “Image Pixel Size = 2.233 nm”. If the image was saved at a different resolution than it was scanned, DP_IMAGE_STORE gives the stored size and the pixel size must be scaled.
And in a Thermo Fisher (FEI) TIFF?
In tag 34682 (or 34680 on older instruments), an INI-style text: the [Scan] section holds PixelWidth in metres (for example 1.953125e-009) and the [Image] section holds ResolutionX.
Why cross-check with the scale bar?
Images get resized, cropped or exported to PNG and lose their metadata; a mismatch between metadata and bar reveals a wrong file, a resized image or a calibration problem before it ruins a measurement.
Are my images uploaded?
No. Everything runs in your browser with JavaScript; the files are read locally and nothing is sent to a server. You can disconnect from the internet after the page has loaded.
Can it read the number printed next to the bar?
Not yet: type the bar length once for the whole folder (or leave it empty for original Zeiss or Thermo Fisher TIFF files, which carry their calibration).