Common Interface to perform Detection algorithm - c++

Question

I am stuck in a situation please help me out of this.
Thought:
To have a common Interface among different Detection algorithms(Say Circle, Triangle and Rectangle).
class IDetectionInterface()
{
public:
virtual void PerformDetection(Image & InputImage, DetectionStruct & DetectionData, DetectionParam & DetParam) = 0;
virtual ~IDetectionInterface()
{
}
};
where Image and DetectionStruct is a structure as below:
struct Image
{
unsigned char * pImageData;
int Width;
int Height;
};
struct DetectionStruct
{
Rect BoundingBox;
DectionType DetType;
};
struct Rect
{
int x;
int y;
int width;
int height;
};
enum DectionType
{
Circle = 0,
Triangle = 1,
Rectangle = 2
}
The Problem for me is that of DetectionParam, as Parameters of Detection Algorithms differ. Say for example
struct RectDetectionParam
{
int param1;
float param2;
double param3;
};
struct TriDetectionParam
{
float param1;
float param2;
double param3;
int param4;
};
struct CirDetectionParam
{
int param1;
float param2;
bool param3;
int param4;
float param5;
};
How can i get this to common interface as above.
Note: I don't want to put all the parameters in one structure which is a easiest solution, But it has its drawback if i change the algorithm then its respective parameters changes and we need to re write the structure again.
And Ofcource Yes, I will have the implementation of the interface(Abstract class)
Thanks in advance

Answer 1

Based on your example you could create a discriminated union to make the parameter sets generic:
struct DetectionParams {
DectionType detectionType; // Discriminator
union {
RectDetectionParam rectDect;
TriDetectionParam triDect;
CirDetectionParam cirDect;
};
};
Which of the union parts is used in the implementation is determined by the discriminator.
Another way is to use something like a parameter set based on unique parameter names (key strings):
struct DetectionParams {
std::map<std::string,std::any> params; // Note that std::any is available
// at the not yet official c++17 standard
};