Eyebrow mapping

All eyebrow mapping geometry is calculated in full-image pixels, including the image's width and height. A fitted axis uses forehead-to-chin reference points to separate face-horizontal position from vertical height. Brow head and tail are midpoints between corresponding upper and lower endpoints. The peak comes from the highest upper-contour point, refined by a bounded concave curve through its neighbours when that fit is usable. The displayed photo crop changes the view, not the mathematics.

The start, arch and tail values are horizontal offsets from the constructed line at the lower-contour height. The overlay uses a horizontal ruler and a faint connector when the actual point sits at another height. Tail lift is the tail's height relative to the head. Head level compares the two sides; gap compares actual and constructed brow-head separation. Each side is rounded to one decimal before the paired mean is rounded again, so the visible calculation can be checked.

The reference scale is 11.7 × 1.054 = 12.3318 divided by the observed mean horizontal iris diameter in pixels. A diameter below 12 pixels is too small for this worksheet. This calculation assumes a reference iris size; it does not measure your personal iris diameter or calibrate camera perspective. Reference millimetres can shift with distance, eye direction, sharpness and the selected landmark contour. There is no fixed ±1 mm accuracy claim.

An available cheek-depth yaw estimate above 10° withholds the eyebrow mapping. If depth alignment is missing, the eyebrow mapping remains available with an unknown-pose note. This is a computational front-view check, not a clinical measurement. Live tracking uses fresh paired frames; stale lines are cleared. Freeze captures the current mirrored frame, turns the camera off, and requires a new still-image analysis for final readings.

Shape descriptions are independent of the reference intervals. Arch rise divided by horizontal length separates straighter, soft and higher arches at 0.14 and 0.24. Arch position separates earlier, middle and later peaks at 58% and 72%. A tail below −2.5 reference mm is described as lower; above 3 mm it is raised. These are explicit product conventions, not attractiveness grades or comparisons with a population.

Natural brows often differ in height, density and growth direction. A balanced eyebrow mapping result may use different pencil marks on each side rather than identical distances. Try a washable adjustment in good light, step back from the mirror, and compare the overall expression. The map cannot evaluate skin conditions, decide whether a treatment suits you, or guarantee the result of waxing, threading or cosmetic procedures.