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No image in this slot Load a PNG or another lossless file. JPEG compression alters pixel values.
To try it out, use generate example blot on the right.
Click a band to measure itClick a box to select Corners resizeBottom handle rotates× or Delete removes Arrows moveAlt+arrows resizeCtrl+Z undoes
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net = Σ(signal) − median(surrounding ring) × area, where signal is 255−brightness for dark bands and brightness for bright ones. Polarity is detected from each image, so nothing to set. Rotated boxes sample the original pixels directly — the image is never rotated, so no interpolation changes a value. Lanes are numbered by x position, not click order. A box edge turns red where it cuts through the band.