convex and concave 中文直譯: 凸凹
下圖為convex例子, xy連線通過一個封閉區域,
任何X,Y連線(集合)都會被包含在這個封閉區域即綠色區域
下圖為concave例子, xy連線通過一個封閉區域,
並不是全部的X, Y連線都會被包含在這個封閉區域(綠色區域),
換句話說,
紅色線段(集合)並不包含在這個封閉區域(綠色區域)
維基百科定義concave
The word concave means curving in or hollowed inward, as opposed to convex.[1]
根據這樣的定義, 所以可以衍生出小時候學過的凹凸透鏡
concave lens 凹透鏡
convex lens 凸透鏡
Concave polygon
A simple polygon that is not convex is called concave,[1] non-convex[2] or reentrant.
一多邊形非凸(convex)可稱作凹(concave)或是非凸(non-convex), 折返(reentrant)
凹多邊形(concave polygon)都會有至少一個內角大於180度(reflex interior angle)
A concave polygon will always have at least one reflex interior angle—
that is, an angle with a measure that is between 180 degrees and 360 degrees exclusive.
reflex angle長得像這樣:
綜合以上, convex和concave應用在影像處理上可以做甚麼用?
值得大家去思考…先寫到這~~~
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