Thank you. Although, after thinking about it. I think that converting JPG to PBM in order to get full pixels may be compromising what I am trying to achieve.
The Tesseract doc Improving the quality of the output <https://tesseract-ocr.github.io/tessdoc/ImproveQuality.html#image-processing> mentions “Willus Dotkom” (Under rescaling) with this link Optical Image Resolution <https://groups.google.com/g/tesseract-ocr/c/Wdh_JJwnw94/m/24JHDYQbBQAJ> This page (Optical Image Resolution) is about the pixel height of capital letters/numbers of source documents. I need an accurate count (not adjusted because it's easier) The image I have included in this post shows my measuring 'ruler' on the right of the *14 * I am looking for a rule or method that is an accepted scientific approach regarding the counting of pixels. On Thu, Mar 16, 2023 at 9:06 PM 'Isidore Paris' via tesseract-ocr < tesseract-ocr@googlegroups.com> wrote: > I don't know how big is your "lot of files"… So, sorry if this doesn't > match: > I use IRFANVIEW (free software) to convert JPG either in PBM or in B&W (2 > COLORS) JPG, with the batch option (open an image and then press letter B > on keyboard) – but maybe you already know Irfanview…? > It converts very good and quite quickly. I just converted 224 files (jpg > b&w 256 colors (greys)) in 40 seconds. > If you only have some hundreds of files, it could be a pretty solution… > But if you have thousands or 10.000's, surely it could be heavy… > > > Il giorno martedì 14 marzo 2023 alle 23:25:49 UTC+1 da...@mranderson.co.nz > ha scritto: > >> Thank you for your input. I appreciate the PBM file type has its uses. >> But my source material is JPG. And there are a lot of files! >> >> On Wed, Mar 15, 2023 at 10:41 AM 'Isidore Paris' via tesseract-ocr < >> tesser...@googlegroups.com> wrote: >> >>> I get the best result with PBM images, i.e b&w. Doing that way, there >>> would be no half-tones… (Don't know if this could help…) >>> >>> >>> >>> Il giorno lunedì 13 marzo 2023 alle 23:17:23 UTC+1 >>> da...@mranderson.co.nz ha scritto: >>> >>>> I'm preparing text images (JPG) for Tesseract OCR conversion to text >>>> files (TXT) I note that it is important to resize my image docs so that >>>> capital letters are about 30-32 pixels in height. See Optimal image >>>> resolution (dpi/ppi) for Tesseract 4.0.0 and eng.traineddata? >>>> <https://groups.google.com/g/tesseract-ocr/c/Wdh_JJwnw94/m/24JHDYQbBQAJ?pli=1> >>>> >>>> I am using the Fiji/ImageJ to count capital letter height in pixels. >>>> From https://imagej.nih.gov/ij/docs/pdfs/ImageJ.pdf >>>> >>>> - Open image file >>>> - Enlarge text (zoom in) >>>> - Draw parallel vertical line beside vertical of number or straight >>>> edge letter >>>> - Select Analyze>Set Scale (see image below) >>>> >>>> [image: fiji first.png] >>>> >>>> How to count pixels? Do I count the 'half pixels'? Where the pixel >>>> 'block' is a half-tone? In other words, for my total count, do I estimate >>>> the true height by including these half-tones. >>>> >>>> Does anyone have a better procedure than this? >>>> >>>> My aim is to come up with a resizing ratio that I can apply to a large >>>> collection of text files using a Python script. This being another step >>>> along the way to preparing docs for Tesseract. >>>> >>>> Any suggestions would be appreciated. >>>> >>> -- >>> You received this message because you are subscribed to a topic in the >>> Google Groups "tesseract-ocr" group. >>> To unsubscribe from this topic, visit >>> https://groups.google.com/d/topic/tesseract-ocr/bZh3j_i8MYU/unsubscribe. >>> To unsubscribe from this group and all its topics, send an email to >>> tesseract-oc...@googlegroups.com. >>> To view this discussion on the web visit >>> https://groups.google.com/d/msgid/tesseract-ocr/2434d564-f2b5-40df-b180-8465bc9c5c42n%40googlegroups.com >>> <https://groups.google.com/d/msgid/tesseract-ocr/2434d564-f2b5-40df-b180-8465bc9c5c42n%40googlegroups.com?utm_medium=email&utm_source=footer> >>> . >>> >> -- > You received this message because you are subscribed to a topic in the > Google Groups "tesseract-ocr" group. > To unsubscribe from this topic, visit > https://groups.google.com/d/topic/tesseract-ocr/bZh3j_i8MYU/unsubscribe. > To unsubscribe from this group and all its topics, send an email to > tesseract-ocr+unsubscr...@googlegroups.com. > To view this discussion on the web visit > https://groups.google.com/d/msgid/tesseract-ocr/5e6e70e8-b1ab-4b1d-8923-9f8f357210f2n%40googlegroups.com > <https://groups.google.com/d/msgid/tesseract-ocr/5e6e70e8-b1ab-4b1d-8923-9f8f357210f2n%40googlegroups.com?utm_medium=email&utm_source=footer> > . > -- You received this message because you are subscribed to the Google Groups "tesseract-ocr" group. To unsubscribe from this group and stop receiving emails from it, send an email to tesseract-ocr+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/tesseract-ocr/CAKu11d2herZ-2HmMt2%2B%3DmrT8zD2B_HgwetZG1-2Xm8Avsqo5Kg%40mail.gmail.com.
