text: Title: Very strange behavior of two-number ocr
  Body: Hi, I'm trying to apply OCR to a captcha image and I'm getting some strange results to share.
  
  When I use `reader = easyocr.Reader(['en'])`, the original captcha image is not recognized at all, but the `255-image` is recognized just fine. Intuitively, this is very strange behavior.
  
  ![original](https://github.com/JaidedAI/EasyOCR/assets/26109705/3876c956-72ec-4780-9725-4ffc56e7fbb8) : original image
  ![inverted](https://github.com/JaidedAI/EasyOCR/assets/26109705/8bae1dac-2f4b-48c6-8be5-b3616cb506b2) : inverted image
  
  `reader.readtext(image, detail = 0, allowlist="0123456789")` returns `['27']`, which is accurate for inverted image but `[]`(nothing detected) for original image.
  
  Is there any guess for why this strange phenomena occurs?