What it does
ELlipserWeb calibrates photos, measures distances and angles, and fits ellipses to bloodstains so you can record impact angle (alpha) and travel direction (gamma). Images and measurements stay on this device.
Getting started
- File → New to name the case, or File → Open to load a saved
.elp project.
- File → Import → Images to add photographs.
- Draw a Scale on a known length so later values are in real units (otherwise lengths stay in pixels). Draw at most one Scale and one Plumb per image.
- Optional: draw a Plumb vector pointing the way gravity acts if the camera was rolled. With Align image to gravity on, the photo rotates to vertical; gamma is always corrected by the plumb offset.
- Use the left tools to measure. Ellipse → Assisted finds stain centers and fits half-ellipses.
- Open the chart icon on a Stains session in Structure for distributions and the stain table.
- File → Save writes the project. File → Export makes a CSV report, Measurements CSV, a printable PDF report, or a marked PNG of the current photo.
Tools and shortcuts
- Scale, Plumb, Measure, Circle, Ellipse, Polyline, Polygon, Text — click a tool, then draw on the photo. Plumb is B.
- Wheel zooms, right-drag pans, Delete removes the selection, F flips an ellipse, Ctrl+Z / Ctrl+Shift+Z undo and redo.
- Per-stain arrows at centers set travel direction; Fit stays near each arrow within the Settings angle tolerance.
- View shows or hides Structure, Properties, Project, and Measurements. Drag a panel heading to float it over the canvas or dock it left/right.
Assisted fitting sliders
On the last assisted-wizard step (and on a Stains session in Properties), three sliders tune Find Centers and Fit Ellipses. Change a value, then run Find Centers or Fit again.
- Color Threshold — How strongly pixels must match your stain color samples versus the background. Raise it to ignore faint or off-color marks; lower it to pick up lighter or less distinct stains.
- Size Threshold — How closely detected blobs must match the small and large size samples from setup. Raise it to keep only stains near those sizes; lower it to allow a wider size range.
- Front / fill — How solid a blob must be (how much of its bounding box is filled). Raise it to drop thin, broken, or sparse patches; lower it if real stains are being filtered out. Larger stains skip this filter.
Capabilities
- Calibrated length, width, alpha, and gravity-corrected gamma for each stain.
- Optional plumb line to correct camera roll and align the image to gravity.
- Assisted detection with dark and light stain samples, detect/exclude regions, and manual marking.
- Stain charts: impact-angle and width histograms, direction rose, width/length vs alpha, and a location map.
- Project metadata, structure tree, and per-object styles.