Photo Stitcher

Finds where overlapping shots match and joins them into one image. Use it to turn scrolling screenshots into one long screenshot, or to join microscope tiles or a document scanned in parts.

How to use

1. Add two or more pictures. Screenshots can be pasted with Ctrl+V; "Sort by name" orders files by the numbers in their names.
2. In "Match overlaps", choose the "Arrangement": "One column (scrolling screenshots)" for screenshots, or "Grid" with "Columns" and "Shooting order" for microscope tiles.
3. Check the overlaps in the "Difference" view and move a picture that is off by dragging it or with the arrow keys.
4. Set "Overlaps", "File type" and "Save size", then press "Download".

How it works

• Only pictures taken by moving sideways or up and down are matched. Landscape panoramas taken by turning the camera are not supported.
• Each neighboring pair is matched by normalized cross-correlation, with a confidence from 0 to 100%. In a grid, the shifts are reconciled by least squares so that errors do not add up.
• Bars that stay in place in scrolling screenshots are detected and cut under "Fixed header and footer".
• A result too large for the browser is saved smaller, and the page says so. Pictures are not uploaded.

Questions and answers

Can I merge scrolling screenshots into one long screenshot?

Yes. Add them in order and choose "One column (scrolling screenshots)". Repeated top and bottom bars are kept only once.

How do I stitch microscope images taken in parts?

Choose "Grid" and set "Columns" and "Shooting order". For pictures with dark edges, turn on "Even out brightness" and "Soften the seam".

Can it stitch landscape panoramas?

No. Pictures taken by turning the camera differ in perspective, so a shift cannot line them up. To place pictures next to each other without matching, use "Place side by side".

What if the automatic match is off?

Find pairs with low confidence in "Shift of each pair" and move the pictures by hand until the overlap looks black in the "Difference" view.