Improve quality of tesseract / DPI of an image
Vahagn Martirosyan
Tesseract works best on images which have a DPI of at least 300 dpi, so it may be beneficial to resize images. For more information see the FAQ.
The problem is that image does not have DPI unless it has no size. The size here does not mean resolution, for example 600x400 pixels. The size means how many inches it has vertically and horizontally, and that how we calculate the DPI (dot per inch). It means if I zoom in or zoom out exactly the same image its DPI will decrease and increase correspondingly. So here is the question, how tesseract opens the image, how tesseract measure the size of iameg and what kind of size that image has at the time when tesseract starts reading and calculate the DPI. It is meaningless to say that image has fixed DPI, it has DPI depending to its size.
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