Calculates an absolute array norm, an absolute difference norm, or a relative difference norm.

nrm = cv.norm(src1)
nrm = cv.norm(src1, src2)
nrm = cv.norm(..., 'OptionName', optionValue, ...)

Input

• src1 first input array.
• src2 second input array of the same size and the same type as src1.

Output

• nrm the calculated norm.

Options

• NormType type of the norm, default 'L2'. One of:
  • Inf
  • L1
  • L2
  • L2Sqr
  • Hamming
  • Hamming2
• Relative if true, computes relative difference, otherwise absolute difference. default false
• Mask optional operation mask; it must have the same size as src1 and logical type. Not set by default.

The functions norm calculate an absolute norm of src1 (when there is no src2):

       { ||src1||_Linf = max(abs(src1(:)))     , if NormType='Inf'
norm = { ||src1||_L1   = sum(abs(src1(:)))     , if NormType='L1'
       { ||src1||_L2   = sqrt(sum(src1(:).^2)) , if NormType='L2'

or an absolute or relative difference norm if src2 is there:

       { ||src1 - src2||_Linf = max(abs(src1(:) - src2(:)))       , if NormType='Inf'
norm = { ||src1 - src2||_L1   = sum(abs(src1(:) - src2(:)))       , if NormType='L1'
       { ||src1 - src2||_L2   = sqrt(sum((src1(:) - src2(:)).^2)) , if NormType='L2'

or:

       { ||src1 - src2||_Linf / ||src2||_Linf , if NormType='Inf' && Relative=True
norm = { ||src1 - src2||_L1 / ||src2||_L1     , if NormType='L1'  && Relative=True
       { ||src1 - src2||_L2 / ||src2||_L2     , if NormType='L2'  && Relative=True

When the mask parameter is specified and it is not empty, the norm is calculated only over the region specified by the mask.

A multi-channel input arrays are treated as a single-channel, that is, the results for all channels are combined.