In this chapter, we provided a deeper view of the highgui module functionality to enrich the user experience. The main elements supplied by OpenCV to build graphical user interfaces are shown in some code samples. Moreover, we reviewed the new Qt functionality inside OpenCV.

The chapter's examples cover topics such as tbarContrast, tbarContrastCallB, drawThings, drawRs, and propertyDlgButtons.

The next chapter will cover the implementation of the most usual methods used for image processing, such as brightness control, contrast and color conversion, retina filtering, and geometrical transformations.