Choi et al used image analysis to determine the severity of nasolabial wrinkles. This is an objective method if photographs are taken in a standardized manner. The authors are from Seoul National University in South Korea.
Patient selection: nasolabial wrinkle
Software: ImageJ
Picture: 8-bit RGB, JPEG format, 2152x2740 pixels, taken under standard lighting conditions.
Grey scale measurement gives values ranging from 255 (pure white) to 0 (pure black).
Grey scale readings were taken along a line running from the philtrum to the cheek and perpendicular to the wrinkle.
Theory: The deeper the wrinkle the darker it is and the lower the grey scale reading. This results in a greater difference with the surrounding non-wrinkled skin.
The baseline grey scale value was taken as the maximum value for the average grey scale readings over the philtrum and cheek.
wrinkle grey scale =
= (baseline grey scale value) - (minimum grey scale value in the wrinkle)
Interpretation:
• The greater the WGS the deeper the wrinkle.
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