Patent ID: 11879774
Assignee: SIGNIFY HOLDING B.V.
Field: Measurement (Instruments)
Classification: CPC G | IPC G

Claim 14:
15. A computer program product when running on a processor is capable of carrying out a method of evaluating a melanopsin active radiation of light, wherein the method comprises the steps of:
taking an image of a light indicator when being illuminated with the light,
wherein the light indicator is for use in evaluating melanopsin active radiation of light, the light indicator comprising a first light indicator element comprising a first light reflective element and a second light indicator element comprising a second light reflective element, the light reflecting elements having different wavelength dependencies of the spectral reflectivity, wherein the light reflecting elements are selected to provide the same intensity ratio of reflected light of two or more different types of light irradiating on the light indicator elements, wherein the two or more different types of light have different spectral power distributions in the visible wavelength range but have the same ratios of the melanopic flux to the luminous flux, wherein the ratio of the melanopic flux to the luminous flux of light is defined as

MEF=1.22(Σ(λ=380){circumflex over ( )}780SPD(λ)m(λ)Δλ)/(Σ(λ=380){circumflex over ( )}780SPD(λ)V(λ)Δλ)   (Eq. 1), wherein SPD(λ) is the spectral power distribution of the light, m(λ) is the melanopic sensitivity function, and V(λ) is the photopic sensitivity, and wherein the light reflecting elements are further selected to provide a different intensity ratio of reflected light of two or more different types of light irradiating on the light indicator elements, wherein the two or more different types of light have different ratios of the melanopic flux to the luminous flux,
calculating the value of the melanopic DER from the intensities of light emanating from the first light indicator element and the second light indicator element using the formula:, melanopic
      ⁢
         
      DER
     
     =
     
      
       k
       ⁡
       (
       
        
         
          
           m
           1
          
          ⁢
          
           R
           m
          
         
         +
         
          
           m
           2
          
          ⁢
          
           G
           m
          
         
         +
         
          
           m
           3
          
          ⁢
          
           B
           m
          
         
        
        
         
          
           p
           1
          
          ⁢
          
           R
           p
          
         
         +
         
          
           p
           2
          
          ⁢
          
           G
           p
          
         
         +
         
          
           p
           3
          
          ⁢
          
           B
           p
          
         
        
       
       )
      
      n
     
    
   
   
    
     (
     
      Eq
      .
         
      9
     
     ), wherein:, Rm, Gm, Bm: mean R, G, B values for the first light reflective element,, Rp, Gp, Bp: mean R, G, B values for the second light reflective element,, k, m1, m2, m3, p1, p2, p3, n: regression parameters.