Look only for digits not working

[illera88]

Environment

• Tesseract Version: 4.1.1#1
• Platform: Win 64 bits

    tessaretAPI = std::make_shared<tesseract::TessBaseAPI>();

    tessaretAPI->SetPageSegMode(tesseract::PageSegMode::PSM_SINGLE_LINE);
    tessaretAPI->SetVariable("tessedit_char_blacklist", "\n!?@#$%&*()<>_-+=/:;'\"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz");
    tessaretAPI->SetVariable("tessedit_char_whitelist", "0123456789");
    tessaretAPI->SetVariable("classify_bln_numeric_mode", "1");

    if (tessaretAPI->Init(".", "eng", tesseract::OEM_DEFAULT)) {
        fprintf(stderr, "Could not initialize tesseract.\n");
        // throw error
        exit(1);
    }
    tessaretAPI->SetPageSegMode(tesseract::PageSegMode::PSM_SINGLE_LINE);
    tessaretAPI->SetVariable("tessedit_char_blacklist", "!?@#$%&*()<>_-+=/:;'\"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz");
    tessaretAPI->SetVariable("tessedit_char_whitelist", "0123456789");
    tessaretAPI->SetVariable("classify_bln_numeric_mode", "1");

// Later

std::string OpenCV_sensor::detect_text(const cv::Mat& img)
{
    tessaretAPI->SetImage((uchar*)img.data, img.size().width, img.size().height, img.channels(), (int)img.step1());
    return tessaretAPI->GetUTF8Text();
}

I'm trying just to detect numbers with tesseract but I'm still getting other than just numeric results.

I've tried to set the restrictions to tessaret before and after calling Init but the results still are alphanumeric.

[Moldoteck]

Check the return of SetVariable. Is it true or false?

[GerfriedC]

Is there a possibility to include a lean unpkg .js only focusing on digit recognition, correcting glare and odd horizon angles?