Implementing your OpenCV filters

Now that your development environment is ready, we can begin the fun part! We will implement three filters using OpenCV:

• FilterOriginal: Does nothing and returns the same picture (lazy!)
• FilterGrayscale: Converts a picture from color to grayscale
• FilterBlur: Smooths the picture

The parent class of all these filters is Filter. Here is the abstract class:

//Filter.h
class Filter
{
public:
    Filter();
    virtual ~Filter();

    virtual QImage process(const QImage& image) = 0;
};

//Filter.cpp
Filter::Filter() {}
Filter::~Filter() {} 

As you can see, process() is a pure abstract method. All filters will implement a specific behavior with this function. Let's begin with the simple FilterOriginal class. Here is FilterOriginal.h:

class FilterOriginal : public Filter
{
public:
 FilterOriginal();
 ~FilterOriginal();

QImage process(const QImage...