Patent ID: 11899040
Assignee: HERE GLOBAL B.V.
Field: Measurement (Instruments)
Classification: CPC G | IPC G

Claim 15:
16. The apparatus according to claim 9, wherein the data representative of the variation in the intensity of light emitted from at least two light sources comprises a spatial frequency F(Ls), and wherein the at least one memory and the program code are further configured to use the at least one processor to cause the apparatus to perform and/or control at least one or more of the following:
obtaining a length/of the segment of the road;
detecting a light intensity signal Ls;
estimating an autocorrelation of the detected light intensity signal Ls:

RLM(τ)=Σn∈1 . . . NLM(n)LM(n−τ);

where N is the total number of samples in Ls;

estimating a number tC of signal samples of the detected signal in one cycle as:, t
      C
    
    =
    
      
        argmax
        τ
      
      ⁢
      
        
      
      ⁢
      
        R
        
          L
          M
        
      
    
  
  ;

estimating a number of cycles NCS Ls at the road segment as:, N
      C
      S
    
    =
    
      N
      
        t
        C
      
    
  
  ,, and
estimating the frequency F(Ls) (e.g. in cycles per meter) as, F
    ⁡
    
      (
      
        L
        s
      
      )
    
  
  =
  
    
      
        N
        C
        S
      
      l
    
    .