There are many ways to learn digital image processing, and the best method will depend on your individual learning style and preferences. Here are some suggestions:

1. Online Courses: There are many online courses available that cover digital image processing. Websites like Coursera, Udemy, and edX offer a wide range of courses taught by experts in the field. Some popular courses include "Digital Image Processing" by Rafael C. Gonzalez and Richard E. Woods on Coursera and "Image Processing with MATLAB" by MathWorks on edX.

2. Books: There are many excellent books on digital image processing. Some popular titles include "Digital Image Processing" by Rafael C. Gonzalez and Richard E. Woods, "Introduction to Digital Image Processing" by Alasdair McAndrew, and "Digital Image Processing Using MATLAB" by Rafael C. Gonzalez, Richard E. Woods, and Steven L. Eddins.

3. Tutorials and Videos: There are many tutorials and videos available on YouTube and other websites that cover digital image processing. Some popular channels include "Computerphile," "The Coding Train," and "OpenCV."

4. Practice: One of the best ways to learn digital image processing is to practice it yourself. You can start by working on small projects and gradually work your way up to more complex tasks. You can also participate in online communities and forums to get feedback on your work and learn from others.

5. Attend Workshops or Conferences: Attending workshops or conferences is a great way to learn from experts in the field and connect with others who are interested in digital image processing. You can find information about workshops and conferences on websites like IEEE and SPIE.