如何根据Photoshop步骤使用CoreImage制作素描图像？

Question

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I want to make a sketch image use CoreImage, first i use photoshop to make it, the steps are as follows: Mono, ColorInvert, DodgeBlend and so on.but next step is that i should use Filter -> Other -> min as the photoshop tell me.i don't know what is the meaning of the CoreImage.the photoshop steps is enter link description here thank you!