Dear piggy, can you elaborate what you did with the images please? The tools you used; and the modifications you did. I was trying to replicate what you did. But, I am not getting what you get. Is scaling up the image the same thing as increasing the DPI of the image?
On Friday, November 3, 2023 at 4:28:49 PM UTC+3 piggy wrote: > I think the biggest improvement came from the blur followed by the right > thresholding. That improves the division of the page into separate letters. > > The added border allowed tesseract to pick up the right-hand side of the > numbers better. I was hoping to pick up the 1's down the left-hand side, > but that didn't work. > > Scaling up is a heuristic trick I've used in the past, and it helped here. > > On Thu, Nov 2, 2023 at 6:36 PM Slartybartfast <[email protected]> > wrote: > >> Thank you! The original has much more border around it. I just cropped it >> for easier viewing here. I already did a little bit of pre-processing but >> looks like I need to do more. Interesting that scaling up improved things. >> According to one analysis done, accuracy depends on character height. >> According to that - I had the optimum character height, but maybe things >> have changed. The original scan was done at 300 dpi. I'll try 600. >> >> Incidentally ... I got so frustrated I wrote my own OCR program today. >> Only took me a few hours. Much more accurate than Tesseract, though working >> with fixed-width fonts makes life a lot easier!! Just divide the image up >> into a grid, and pattern match each "cell". As I was only interested in the >> numbers, I only had 16 (hex digits) to match against. >> >> Cheers >> >> >> On Thursday, November 2, 2023 at 12:43:12 PM UTC piggy wrote: >> >>> I added more white space around the target text by scaling the canvas to >>> 500 pixels wide, and then scaled up the whole image by a factor of 2. >>> >>> -230 6 5O >>> >>> 90 6 50 >>> >>> 90 6 -100 >>> 130 6 -100 >>> 130 6 -150 >>> >>> On Thu, Nov 2, 2023 at 8:35 AM La Monte H. P. Yarroll < >>> [email protected]> wrote: >>> >>>> I had a little success applying 2.5 pixels of blur and then >>>> thresholding at 217-255. FWIW, I used gimp for the preprocesing. Here's >>>> what I got after just a few minutes: >>>> a i @) >>>> >>>> -230 & 50 >>>> 90 6 50 >>>> 90 6 -100 >>>> >>>> 130 6 >>>> 130 6 >>>> >>>> ~100 >>>> -130 >>>> >>>> I don't know what happened to the first column or why the last 2 lines >>>> got split the way they did. >>>> >>>> >>>> On Wed, Nov 1, 2023 at 4:30 PM Slartybartfast < >>>> [email protected]> wrote: >>>> >>>>> Doesn't anybody have any ideas? :-( >>>>> >>>>> On Tuesday, October 24, 2023 at 5:40:20 PM UTC+1 Slartybartfast wrote: >>>>> >>>>>> Hi >>>>>> I am a new tesseract user, and I'm really struggling to get it to >>>>>> produce any kind of sensible results, especially with numerical text. I >>>>>> have some text that looks like this: >>>>>> [image: example_input.jpg] >>>>>> I've read the documentation, and looked through the parameter list, >>>>>> and I added the following to the command line: >>>>>> --psm 6 >>>>>> -c preserve_interword_spaces=1 >>>>>> -c textord_dotmatrix_gap=6 >>>>>> -c classify_bln_numeric_mode=1 >>>>>> -c rej_alphas_in_number_perm=1 >>>>>> >>>>>> But I just get garbage out: >>>>>> >>>>>> Oo -250 6 3a >>>>>> 190 & So >>>>>> 190 6 -100 >>>>>> 1 $1290 6 ~140 >>>>>> 1 $130 6 ~150 >>>>>> >>>>>> I've tried all sorts of additional image processing to try and >>>>>> improve the look of the text, but none of it works. In fact, this is the >>>>>> best output of seen. It's usually worse. I'm really hoping someone who >>>>>> has >>>>>> worked with dot-matrix input can offer some magic incantation to make >>>>>> tesseract come to its senses. Thanks. >>>>>> >>>>> -- >>>>> 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 [email protected]. >>>>> To view this discussion on the web visit >>>>> https://groups.google.com/d/msgid/tesseract-ocr/15797f86-58c9-4e71-b316-54f663d04cbfn%40googlegroups.com >>>>> >>>>> <https://groups.google.com/d/msgid/tesseract-ocr/15797f86-58c9-4e71-b316-54f663d04cbfn%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 [email protected]. >> > To view this discussion on the web visit >> https://groups.google.com/d/msgid/tesseract-ocr/5c364cf1-076a-43e4-86f2-61b925b9d6c3n%40googlegroups.com >> >> <https://groups.google.com/d/msgid/tesseract-ocr/5c364cf1-076a-43e4-86f2-61b925b9d6c3n%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 [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/tesseract-ocr/6d8cefec-0521-4b83-8a0f-74ba85a10bc7n%40googlegroups.com.
