Rating captchas

rate_captcha.R

# install.packages(c("magick", "tesseract"))
stopifnot(packageVersion('magick') >= 2.0)
stopifnot(packageVersion('tesseract') >= 4.0)

# Use in rstudio to see captcha images 
rate_captcha <- function(n = 10){
  success <- rep(NA, n)
  for(i in seq_len(n)){
    repeat{
      img <- magick::image_read('https://issues.apache.org/jira/captcha')
      text <- tesseract::ocr(img)
      if(nchar(text)) break
    }
    print(img)
    cat("Tesseract guess:", text, "\n")
    success[i] <- askYesNo("Is this correct?", prompts = c("Yes", "No", "Cancel"))
  }
  cat(sprintf("Tesseract Success rate: %d%%\n", mean(success) * 100))
}