Hi Alex, you need to pre process the image a little. First negate it, tesseract expect dark on white background text.
Then use --psm 6 to tell tesseract that this is a single block or text and not a complex page to split in paragraphs. Also try psm 7, single line. tesseract --psm 6 cropped_image.jpg - 1.4 95500>0 Now by stretching the contrast (or and OTSU/adaptive threshold) and straightening the image I get (almost) correct results, see the attached image. 1 4 9 55 0 5 Ideally you want an image as simple as possible, black text on white background. You may also try to crop the black border out, if possible. Have a look here on how to isolate blocks of text: https://www.pyimagesearch.com/2017/07/17/credit-card-ocr-with-opencv-and-python/ https://www.pyimagesearch.com/2017/02/20/text-skew-correction-opencv-python/ Bye Lorenzo Il giorno sab 13 apr 2019 alle ore 19:36 alex kelly <[email protected]> ha scritto: > Hello, > > I'm trying to OCR a small grey scale image, its for a energy meter but it > says the image is to small - the full response is below: > > pi@OCRReader:~ $ tesseract test_images/cropped_image.png out > Tesseract Open Source OCR Engine v3.04.01 with Leptonica > Error in pixGenerateHalftoneMask: pix too small: w = 230, h = 50 > Empty page!! > Error in pixGenerateHalftoneMask: pix too small: w = 230, h = 50 > Empty page!! > > How can I make tesseract-ocr read the value? > > I can send this to google computer vission API but i would rather do this > on the device (rather than sending it to the cloud) and I was recommended > tesseract. > If there is a better solution, please let me know. > > 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 post to this group, send email to [email protected]. > Visit this group at https://groups.google.com/group/tesseract-ocr. > To view this discussion on the web visit > https://groups.google.com/d/msgid/tesseract-ocr/2314d522-ac6d-4abc-8d17-42a198503b7d%40googlegroups.com > <https://groups.google.com/d/msgid/tesseract-ocr/2314d522-ac6d-4abc-8d17-42a198503b7d%40googlegroups.com?utm_medium=email&utm_source=footer> > . > For more options, visit https://groups.google.com/d/optout. > -- 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 post to this group, send email to [email protected]. Visit this group at https://groups.google.com/group/tesseract-ocr. To view this discussion on the web visit https://groups.google.com/d/msgid/tesseract-ocr/CAMgOLLzWRr8FNptY82E9V32-6MhQJs9N9Z1C7rTGO%3DPeUg%3D5ww%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
