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| Version | User | Scope of changes |
|---|---|---|
| Jan 19 2009, 3:38 PM EST (current) | vibraimage | 17 words added |
| Jan 19 2009, 3:28 PM EST | vibraimage | 6 words added, 2 words deleted |
Changes
Key: Additions Deletions
Amplitude vibraimage (AV) characterized the amplitude of object vibration. It does not mean that AV measures the object displacement (mm), correctly it measures the amplitude of signal changing (Voltage or bit) in every image pixel for frame difference accumulation period. AV [1,2] calculates by the following equation:
where:
A x,y - is the resulting signal of the x,y-th element of the amplitude vibraimage calculated in time period for N frames;
U x,y,i - the real signal of x,y element in the frame with number i;
U x,y (i+1) - the real signal of x,y element in the frame with number i+1;
N - the number of frames being processed in the frame sequence;
D - the threshold value, typically equal to the image noise level.
Of course, real AV calculation algorithm is more complicated than given equation and includes a number of filtered settings and adjusting [3].
AV depends on several factors, such as object movement, accumulation period (N), object illumination, object optical contrast, etc. Vibraimage software displays AV by the standard 256 gradation scale, one color for the one bit of AV.
Amplitude vibraimage samples captured with different number of accumulated frames N(10, 50, 100) are below:
Together with frequency vibraimage (FV), amplitude vibraimage are the base in vibraimaging processing and head movements characteristics.
References
1. Viktor Minkin. Vibraimage (Russian language). Renome, 2007.
2. US Patent 7346227, Method and device for image transformation. Viktor Minkin, et al.
3. Emotion Recognition System VibraImage Version 7.0 Manual, Elsys Corp., publications, 2008
where:
A x,y - is the resulting signal of the x,y-th element of the amplitude vibraimage calculated in time period for N frames;
U x,y,i - the real signal of x,y element in the frame with number i;
U x,y (i+1) - the real signal of x,y element in the frame with number i+1;
N - the number of frames being processed in the frame sequence;
D - the threshold value, typically equal to the image noise level.
Of course, real AV calculation algorithm is more complicated than given equation and includes a number of filtered settings and adjusting [3].
AV depends on several factors, such as object movement, accumulation period (N), object illumination, object optical contrast, etc. Vibraimage software displays AV by the standard 256 gradation scale, one color for the one bit of AV.
Amplitude vibraimage samples captured with different number of accumulated frames N(10, 50, 100) are below:
Together with frequency vibraimage (FV), amplitude vibraimage are the base in vibraimaging processing and head movements characteristics.
References
1. Viktor Minkin. Vibraimage (Russian language). Renome, 2007.
2. US Patent 7346227, Method and device for image transformation. Viktor Minkin, et al.
3. Emotion Recognition System VibraImage Version 7.0 Manual, Elsys Corp., publications, 2008
