[jira] [Commented] (TIKA-2235) Use Tesseract's recommended DPI for PDF images

["Tim Allison (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/TIKA-2235?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15890073#comment-15890073 ] 

Tim Allison commented on TIKA-2235:
-----------------------------------

[~mcaruanagalizia], I'm doing a pdf image degradation study to sanity check tika-eval's common tokens metric.  I found that with the default image type ("png"), dpi doesn't apply. I also found that dpi didn't have an effect on jpeg...image quality, though, does.  What image types are you using? 

> Use Tesseract's recommended DPI for PDF images
> ----------------------------------------------
>
>                 Key: TIKA-2235
>                 URL: https://issues.apache.org/jira/browse/TIKA-2235
>             Project: Tika
>          Issue Type: Improvement
>          Components: parser
>    Affects Versions: 1.14
>            Reporter: Matthew Caruana Galizia
>            Priority: Minor
>              Labels: ocr, pdf
>             Fix For: 2.0, 1.15
>
>
> From the [Tesseract wiki|https://github.com/tesseract-ocr/tesseract/wiki/ImproveQuality]:
> {quote}
> Tesseract works best on images which have a DPI of at least 300 dpi....
> {quote}
> PDFParserConfig is currently initialised with a value of 200 for ocrDPI.



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