Digital Image Processing


Outline and Learning Guide




Learning Objectives

  1. Explain why the ability to perform digital processing of radiographic images is a significant advantage.

  2. Identify the quality characteristics of medical images that can be changed by digital processing.

  3. Describe the general relationship between image contrast and pixel values.

  4. Describe the general process of changing image contrast by using look up tables (LUT).

  5. Describe and illustrate how the contrast characteristics produced by LUT processing can be represented by graphs.

  6. Draw and explain graphs comparing LUT processing that produces different image contrast characteristics.

  7. Describe how LUT processing can produce an image with an inverted brightness scale.

  8. Briefly describe the possible advantages of viewing radiographs in the inverted form.

  9. Identify the operator controlled functions on a digital radiography system that selects a specific LUT for image processing.

  10. Draw a simple scale representing the range of pixel values in a recorded digital image and use it to illustrate and describe the process of windowing.

  11. Define and illustrate the concepts of window center and window width.

  12. Describe the general relationship between window with and the contrast in a displayed image.

  13. Describe a possible clinical advantage of changing window level (center) when viewing an image.

  14. Briefly describe the image contrast characteristics in the three segments or regions of the pixel value scale produced by the window.

  15. Describe how the process of blurred (un-sharp) mask subtraction can increase the visibility of detail in images.

  16. Identify some clinical applications in which the blurred mask subtraction process might be useful.



Text Reference

Physical Principles of Medical Imaging, 2nd Ed
Chapter 22

Medical Physics Publishing,



Mind Map