Hello, need advice in solving this type of captcha

[celestialhorizon]

Hello, these are my captcha images.

Characters are only from 0 to 8 (no 9)

Please provide at least 10 example images of the CAPTCHA system:

Please provide the full JavaScript source to what you've already tried:

var cbl = new CBL({
  preprocess: function(img) {
      img.debugImage("debugPreprocessed");
      img.cropRelative(70, 2, 70, 2);
      img.debugImage("debugPreprocessed");
      img.binarize(20);
      img.debugImage("debugPreprocessed");
  },
  character_set: "012345678",
  exact_characters: 4,
  pattern_width: 25,
  pattern_height: 25,
  pattern_maintain_ratio: true,
  allow_console_log: true,
  blob_console_debug: true,
  perceptive_colorspace: false,
  blob_debug: "debugSegmented"
});

Result :

I need advice, what else should I do so I can get rid of the lines in the background. I've read some solutions from issue 2019 till now. But what I did actually made it worse, such as using convolute and blur. so this is the only thing I think removes the line to be thinner.

Now there are still some characters sticking together and I'm a bit confused when playing the blob setting.

Thank you for your time.