Those creatures have long had four-color vision, but a key difference is that their fourth type of color detector is in the high-frequency ultraviolet range, beyond where humans can see.
这些动物早已拥有四色觉，但关键的区别是，他们的第四种颜色位于高频的紫外线区域，在人类可视范围之外。
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This new way bases on the principle of pyroelectric detector and defines the quantity of compensation according to the temperature difference between target and its surrounding.