when to normalize data [closed]

edit

Regarding raw image data in opencv at what point am I supposed to normalize the data? While calculating the Normal vector to a plane I get 2 answers depending on when I normalize the data e.g. right away or later. Is there a hard answer for this?

Normal line from normalized points/vectors <a,b,c> =[0, -0, -0.618409]
Normal line from raw points/vectors: <a,b,c> =[0, -0, -140756]


calculate_vector_from_points(cornerNorm1, cornerNorm2, vec12); 
calculate_vector_from_points(cornerNorm1, cornerNorm3, vec13);
vec_cross_product_2 = vec12.cross(vec13);
std::cout << "Vector 13 =" << vec13 << std::endl;
std::cout << "Vector 12 =" << vec12 << std::endl;
std::cout << "Normal line from normalized points/vectors <a,b,c> =";
std::cout << vec_cross_product_2;
Point3d raw_vec12(0, 0, 0);
Point3d raw_vec13(0, 0, 0);
calculate_vector_from_points(raw_1, raw_2, raw_vec12); 
calculate_vector_from_points(raw_1, raw_3, raw_vec13);
Point3d vec_cross_product_3 = raw_vec12.cross(raw_vec13);
std::cout << std::endl;
std::cout << "Normal line from raw points/vectors: <a,b,c> =" << vec_cross_product_3;