Training Tesseract 4.1.1 from scratch for Urdu

[sameearif88]

At iteration 144912/245400/245403, Mean rms=0.863%, delta=1.017%, char train=2.05%, word train=12.389%, skip ratio=0.1%,  wrote checkpoint.

At iteration 144959/245500/245503, Mean rms=0.862%, delta=1.018%, char train=2.103%, word train=12.508%, skip ratio=0.1%,  wrote checkpoint.

At iteration 145004/245600/245603, Mean rms=0.867%, delta=1.047%, char train=2.135%, word train=12.522%, skip ratio=0.1%,  wrote checkpoint.

At iteration 145048/245700/245703, Mean rms=0.869%, delta=1.05%, char train=2.158%, word train=12.616%, skip ratio=0.1%,  wrote checkpoint.

At iteration 145100/245800/245803, Mean rms=0.879%, delta=1.099%, char train=2.245%, word train=12.822%, skip ratio=0.1%,  wrote checkpoint.

At iteration 145146/245900/245903, Mean rms=0.881%, delta=1.088%, char train=2.331%, word train=13.066%, skip ratio=0.1%,  wrote checkpoint.

At iteration 145190/246000/246003, Mean rms=0.881%, delta=1.103%, char train=2.372%, word train=12.986%, skip ratio=0%,  wrote checkpoint.

UpdateSubtrainer:Sub:At iteration 143875/244300/244302, Mean rms=0.867%, delta=1.051%, char train=2.271%, word train=13.103%, skip ratio=0%, 
UpdateSubtrainer:Sub:At iteration 143914/244400/244402, Mean rms=0.861%, delta=1.049%, char train=2.163%, word train=12.783%, skip ratio=0%, 
UpdateSubtrainer:Sub:At iteration 143961/244500/244502, Mean rms=0.861%, delta=1.054%, char train=2.194%, word train=12.922%, skip ratio=0%, 
UpdateSubtrainer:Sub:At iteration 143997/244600/244602, Mean rms=0.862%, delta=1.059%, char train=2.154%, word train=12.906%, skip ratio=0%, 
UpdateSubtrainer:Sub:At iteration 144039/244700/244702, Mean rms=0.85%, delta=1.027%, char train=2.106%, word train=12.496%, skip ratio=0%, 
UpdateSubtrainer:Sub:At iteration 144082/244800/244802, Mean rms=0.842%, delta=0.995%, char train=2.069%, word train=12.274%, skip ratio=0%, 
UpdateSubtrainer:Sub:At iteration 144117/244900/244902, Mean rms=0.835%, delta=0.988%, char train=1.973%, word train=11.892%, skip ratio=0%, 
Compute CTC targets failed!
UpdateSubtrainer:Sub:At iteration 144161/245000/245003, Mean rms=0.834%, delta=0.99%, char train=1.963%, word train=11.918%, skip ratio=0.1%, 
UpdateSubtrainer:Sub:At iteration 144211/245100/245103, Mean rms=0.833%, delta=0.991%, char train=1.948%, word train=11.883%, skip ratio=0.1%, 
UpdateSubtrainer:Sub:At iteration 144249/245200/245203, Mean rms=0.815%, delta=0.917%, char train=1.82%, word train=11.36%, skip ratio=0.1%, 
UpdateSubtrainer:Sub:At iteration 144290/245300/245303, Mean rms=0.809%, delta=0.907%, char train=1.849%, word train=11.396%, skip ratio=0.1%, 
UpdateSubtrainer:Sub:At iteration 144333/245400/245403, Mean rms=0.813%, delta=0.91%, char train=1.831%, word train=11.293%, skip ratio=0.1%, 
UpdateSubtrainer:Sub:At iteration 144375/245500/245503, Mean rms=0.817%, delta=0.908%, char train=1.866%, word train=11.297%, skip ratio=0.1%, 
UpdateSubtrainer:Sub:At iteration 144418/245600/245603, Mean rms=0.823%, delta=0.931%, char train=1.936%, word train=11.454%, skip ratio=0.1%, 

I am getting "Compute CTC targets failed errors on some iterations.

[stweil]

Please look for other issues with the same error message. There are lots of them. I also suggest to use Tesseract 5.0.1 for training.

[sameearif88]

@stweil I tried training with Tesseract 5.0.1 and figured out the files which where causing this problem. Previously posted issues suggest that there might be some formatting problem in the box file, however I checked the box files, which were causing the problem, in jTessBoxEditor and the rendered box looks fine. I have also attached box/tif pair.

https://drive.google.com/file/d/1E0NhtHC5GGDCywnA0xT3WxhnxSLNQcg0/view?usp=sharing