How to manipulate quaternions numbers in matlab ?

I am a new user in matlab. I have an image with four spectral bands (R, B, G, n NIR) and i want to calculate a quality index which use the quaternions numbers (i.e: z= a+bi+cj+dk) in order to perform a comparison between two images (reference and test image)

My problem is as follow : i want to calculate the average, the covariance, the standard deviation etc.. of a quaternion number, in order to calculate the quality index. I want to know if i can use these types of numbers like others to perform these operations! I need your help, Regards

Answer 1

[Jan]

You can use a standard [1 x 4] vector as quaternion.

Please explain what the average of a quarternion number is. Usually you need a set of values to obtain an average.

[shiraz karray]

Thank you for your answer I want to set a quaternion that composed from radiance values of a given image pixel (four spectral bands: a,b,c and d) i.e: z1= a+b*i+j*c+k*d so i want to calculate the average of this quatrenion and also the standard deviation.