Radiation-based dermatological devices and methods

A self-contained, hand-held device for providing a dermatological treatment, the device comprising:

• a device body configured to be handheld by a user;
• a radiation source supported in the device body, the radiation source including a beam source configured to generate an energy beam;
• an application end configured to be manually moved across the surface of the skin during a treatment session;
• a displacement control system including:
• a single-pixel displacement sensor configured to dynamically detect a magnitude of a single parameter, and generate a single time-based signal indicating the detected magnitude of the single detected parameter over time;
• and
• electronics configured to:
• automatically identify a series of a particular type of intrinsic skin feature in the skin based on the single time-based signal generated by the single time-based signal displacement sensor;
• count a number of the identified intrinsic skin features;
• determine a displacement of the device relative to the skin based on the counted number of the identified intrinsic skin features;
• and
• control at least one operational parameter of the device based on the determined displacement of the device relative to the skin;
• wherein the device does not calculate or otherwise determine a speed of movement of the device.