如何检测扫描文档的方向？ [英] how to detect orientation of a scanned document?

问题描述

我会检测并在必要时更正扫描的文档图像的方向。我已经能够校正文档，但仍然可能发生，文档是颠倒的，需要旋转180°。

I'd to detect and, if necessary, correct the orientation of a scanned document image. I am already able to deskew documents, however it still might occur, that a document is upside down and it needs to be rotated by 180°.

使用 tesseract '可以使用以下代码确定文档的方向：

Using tesseract's layout analysis feature it should be possible to determine a document's orientation using this code:

    tesseract::TessBaseAPI api; 
    api.Init(argv[0], "eng");
    api.SetImage(img); 
    api.SetPageSegMode(tesseract::PSM_AUTO_OSD); 
    tesseract::PageIterator* it = api.AnalyseLayout();

    tesseract::Orientation orient;
    tesseract::WritingDirection dir;
    tesseract::TextlineOrder order; 
    float f;
    it->Orientation(&orient, &dir, &order, &f); 

    if(orient == tesseract::Orientation::ORIENTATION_PAGE_UP)
        std::cout << "Page Up\t"; 
    else if(orient == tesseract::Orientation::ORIENTATION_PAGE_LEFT)
        std::cout << "Page Left\t"; 
    else if(orient == tesseract::Orientation::ORIENTATION_PAGE_DOWN)
        std::cout << "Page Down\t"; 
    else if(orient == tesseract::Orientation::ORIENTATION_PAGE_RIGHT)
        std::cout << "Page Right\t";

然而，代码似乎不能正常工作，因为它总是返回 ORIENTATION_PAGE_UP ，当文档为纵向格式时， ORIENTATION_PAGE_LEFT （可以使用 ORIENTATION_PAGE_DOWN 和 ORIENTATION_PAGE_RIGHT ，但不会返回）。

However the code doesn't seems to work correctly as it always returns ORIENTATION_PAGE_UP when a document is in portrait format and ORIENTATION_PAGE_LEFT when it is in landscape format. (ORIENTATION_PAGE_DOWN and ORIENTATION_PAGE_RIGHT can be used, but are never returned).

A。）上面的代码有什么问题吗？

推荐答案

如何确定文档的方向？检测率然后做同样的事情翻转？更好的速度给出了正确的方向。

What about just running your detection evaluate the detection rate and then doing the same thing flipped ? The better rate gives the right direction.

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