Device for dental plaque detection

Device for dental plaque detection, comprising:

• light emitting means for emitting light in the direction of a tooth (T) and thereby illuminating the tooth (T);
• light receiving means for receiving light scattered from the illuminated tooth (T) at two different distances from the light emitting means;
• light detecting means for detecting the light received by the light receiving means and generating a detection signal (x) representing at least one property of the detected light;
• and
• processing means for determining a ratio R of the intensity of the detected light (Isd, Ild) at the two different distances, particularly a ratio R which is defined as
• R
• =
• I
• ld
• 
• (
• λ
• )
• I
• sd
• 
• (
• λ
• )
• where Ild(λ) represents the intensity of the light at a wavelength λ detected at a relatively long distance from the light emitting means, and Isd(λ) represents the intensity of the light at the same wavelength λ detected at a relatively short distance from the light emitting means.

Device for dental plaque detection, comprising:

• light emitting means for emitting light in a spectrum of wavelengths in the direction of a tooth (T) and thereby illuminating the tooth (T);
• light receiving means for receiving light scattered from the illuminated tooth (T);
• light detecting means for detecting the light received by the light receiving means and generating a detection signal (x) representing at least one property of the detected light;
• and
• processing means adapted to determine a reduced scattering coefficient μ′s(λ) of the detected light as a function of the wavelength λ of the light, particularly a reduced scattering coefficient which is defined as
• μ
• s
• ′
• 
• (
• λ
• )
• =
• α
• 
• [
• ρ
• 
• (
• λ
• λ
• 0
• )
• -
• b
• +
• (
• 1
• -
• ρ
• )
• 
• (
• λ
• λ
• 0
• )
• -
• 4
• ]
• where λ0 represents a wavelength normalization value, α represents the reduced scattering amplitude at λ0, b represents the Mie scattering slope, and ρ represents the Mie-to-total reduced scattering fraction.

Device for dental plaque detection, comprising:

• light emitting means for emitting light in a spectrum of wavelengths in the direction of a tooth (T) and thereby illuminating the tooth (T);
• light receiving means for receiving light scattered from the illuminated tooth (T);
• light detecting means for detecting the light received by the light receiving means and generating a detection signal (x) representing at least one property of the detected light;
• and
• processing means are adapted to determine a ratio S of the intensity of the detected light at two different wavelengths, particularly a ratio S which is defined as
• S
• =
• I
• 
• (
• λ
• 1
• )
• -
• I
• 
• (
• λ
• 2
• )
• I
• 
• (
• λ
• 1
• )
• +
• I
• 
• (
• λ
• 2
• )
• where I represents the normalized intensity, λ1 represents a first wavelength, and λ2 represents a second wavelength.

Device for dental plaque detection, comprising:

• light emitting means for emitting light in the direction of a tooth (T) and thereby illuminating the tooth (T);
• light receiving means for receiving light scattered from the illuminated tooth (T);
• light detecting means for detecting the light received by the light receiving means are adapted to image a speckle pattern at the tooth surface at two different instances;
• and
• processing means adapted to determine a correlation C(t) of the two different speckle patterns, wherein the correlation C(t) of the two different speckle patterns is calculated as
• C
• 
• (
• t
• )
• =
• Σ
• x
• ,
• y
• 
• [
• I
• 
• (
• x
• ,
• y
• ,
• 0
• )
• -
• I
• 
• (
• x
• ,
• y
• ,
• 0
• )
• _
• ]
• 
• [
• I
• 
• (
• x
• ,
• y
• ,
• t
• )
• -
• I
• 
• (
• x
• ,
• y
• ,
• t
• )
• _
• ]
• Σ
• x
• ,
• y
• 
• [
• I
• 
• (
• x
• ,
• y
• ,
• 0
• )
• -
• I
• 
• (
• x
• ,
• y
• ,
• 0
• )
• _
• ]
• 
• [
• I
• 
• (
• x
• ,
• y
• ,
• 0
• +
• δ
• )
• -
• I
• 
• (
• x
• ,
• y
• ,
• 0
• +
• δ
• )
• _
• ]
• where x,y represent the pixels of the region of interest, I(x,y,0) represents a measured intensity image of the region of interest at time 0, which is a reference image, I(x,y,t) represents a measured intensity image of the region of interest at time t>0, I(x,y,0+δ) represents a measured intensity image of the region of interest which is taken immediately after the reference image, and the top bars indicate spatial average values of the images.