Keycap characters on keyboards are key elements that identify the function of each key. Formed through processes like injection molding, laser engraving, or pad printing, they are commonly found on computer keyboards, mechanical keyboards, and various input devices. They mainly consist of a keycap base (mostly made of ABS or PBT plastic) and a character layer on the surface, where the clarity of characters directly affects user experience.
Its inspection pain points are significant: characters are small in size and diverse in form (letters, symbols, icons, etc.), prone to defects such as missing strokes, blurriness, discoloration, or missing prints; reflections or texture interference on the plastic keycap surface lead to low imaging contrast; traditional manual inspection is inefficient and subjective, while conventional vision algorithms lack sufficient accuracy in identifying subtle character defects, making it difficult to ensure consistent character quality.
