Selection of the subsection point is the key to enhance low contrast image under light background by subsection linear transformation.

采用分段线性变换对白天亮背景下低对比度图像序列进行对比度增强，最关键的是分段点的选取。

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When you use a selection tool, the Transparent Background and Opaque Background options appear in the option selector on the Image Editor toolbar (as seen below).

当使用选择工具时，“透明背景”和“不透明背景”选项出现在“图像编辑器”工具栏上的“选项”选择器中(如下所示)。

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Opaque Background (o) : Existing image is obscured by all parts of the selection.

不透明背景(O)：现有图像被选定内容的所有部分遮掩。

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