How to detect letters or numbers in MATLAB?

I'm working on a college project, I need to detect letters or numbers. I used OCR and it worked with this image that I captured with the camera:

Code:

   %%Find and Highlight Text in an Image
    % Copyright 2015 The MathWorks, Inc.
    businessCard = imread('texto_1.png');
    ocrResults = ocr(businessCard);
    bboxes = locateText(ocrResults, 'C', 'IgnoreCase', true);
    Iocr = insertShape(businessCard, 'FilledRectangle', bboxes);
    figure; imshow(Iocr);

but when I tried with this image, it did not work:

Does anyone know how I can solve this problem? Or do you have any code so I can mirror?

I'm grateful already!

[Image Analyst]

Try the color thresholder app on the Apps tab of the tool ribbon, or see some color segmentation demos in my File Exchange: https://www.mathworks.com/matlabcentral/fileexchange/?term=authorid%3A31862&sort=downloads_desc

Answer 1

[Image Analyst]

ocr() says that the characters must be at least 20 pixels high. Yours are right at that, so it's possible that you don't have enough resolution.

You might try deep learning instead.

[Raphael Ferreira]

Can you suggest me some way to learn this subject deeply?

[Raphael Ferreira]

I see you must know how to detect colors. Do you have any lyrics that can guide me? Because I tried to detect directional colors like pink, purple, lime green but I could not tell. That's why I'm trying with letters or numbers.

[Raphael Ferreira]

Understand! I'll try.

But if you know and can help me privately, here is my email: [e-mail]

[Florian Morsch]

To detect colors i would recommend to use the HSV (or HSL) color space. Its easier to detect colors here, because you have a specific range in which a color appears. You can then filter you image for that specific color range and detect it. This for example might help: https://de.mathworks.com/matlabcentral/fileexchange/18440-color-detection-using-hsv-color-space--training-and-testing-

[Image Analyst]

Try the Color Thresholder on the Apps tab of the tool ribbon.

[Raphael Ferreira]

I think I'm beginning to understand. Soon I will post the result. Thank you both!