A real-time evaluation method for a virtual reality (VR) immersion effect, comprising following steps:
- S1:
- equipping a participant with a VR imaging apparatus with headphones and a multi-channel electroencephalogram measurement device and collecting an electroencephalogram signal of the participant by the multi-channel electroencephalogram measurement device, wherein when collecting the electroencephalogram signal, based on an international 10-20 system and related brain region distribution, electrodes F7 and F8 are selected for calculating a degree of emotional arousal, and electrodes FP1, FPz, and FP2 are selected for calculating a degree of cognitive absorption;
- S2:
- collecting an electroencephalogram signal of the participant in a resting state and performing preprocessing on the collected electroencephalogram signal to remove noise signal interference and obtain preprocessed EEG data, performing wavelet transform on the preprocessed EEG data to yield rhythm waves and energy of different frequency bands α, β, and θ for i time points and j electrodes, designated as αij, βij, and θij, and inputting the rhythm waves and energy of different frequency bands α, β, and θ for i time points and j electrodes into a formula for calculating a mean degree of emotional arousal and a formula for a mean degree of cognitive absorption to obtain the mean degree of emotional arousal and the mean degree of cognitive absorption in the resting state, wherein the formula for calculating the mean degree of emotional arousal and the formula for the mean degree of cognitive absorption are as follows:
- L
- A
- =
- 1
- mn
-
- ∑
- i
- =
- 1
- m
- ∑
- j
- =
- 1
- n
- β
- ij
- α
- ij
- ,
- and
-
- L
- F
- =
- 1
- mn
-
- ∑
- i
- =
- 1
- m
- ∑
- j
- =
- 1
- n
- θ
- ij
- +
- α
- ij
- β
- ij
- ,
- wherein LA represents the mean degree of emotional arousal;
- LF represents the mean degree of cognitive absorption;
- i represents time, namely, an ith second;
- m represents measurement duration in the resting state, in other words, a measurement lasts m seconds;
- j represents an electroencephalogram collection position, namely, a jth electrode;
- and n represents a quantity of electrodes, in other words, in the formula for the mean degree of emotional arousal, n=2, and in the formula for the mean degree of cognitive absorption, n=3;
- S3:
- playing a three-dimensional (3D) video as a visual stimulus source to the participant by using the VR imaging apparatus with headphones to enable the participant to be in a virtual environment with relatively closed vision and hearing;
- and collecting an original electroencephalogram signal synchronously;
- S4:
- performing real-time preprocessing and wavelet transform on original electroencephalogram signals of electrodes located in prefrontal and anterior temporal regions to obtain rhythm waves and energy of frequency bands α, β, and θ;
- S5:
- calculating a real-time degree of emotional arousal and a real-time degree of cognitive absorption based on results of S2 and S4 based on following formulas:
- A
- i
- =
- 1
- n
-
- ∑
- n
- j
- =
- 1
-
- β
- ij
- α
- ij
- -
- L
- A
- L
- A
- ,
- and
- F
- i
- =
- 1
- n
-
- ∑
- n
- j
- =
- 1
-
- θ
- ij
- +
- α
- ij
- β
- ij
- -
- L
- F
- L
- F
- ,
- wherein Ai represents the degree of emotional arousal, and Fi represents the degree of cognitive absorption;
- S6:
- calculating an immersion index in real time based on the degree of emotional arousal and the degree of cognitive absorption in S5 based on following formula:
- Ei=λ*Ai+(1−λ)Fi,
- wherein λ∈[0,1], and its specific value is determined based on a feature of video content;
- and
- S7:
- grading an immersion effect into three levels based on a time-varying curve of the immersion index, in such a manner to convert a spontaneous electrophysiological activity generated in a user's brain during human brain works into a quantified and visualized immersion index, and to provide a personalized immersion evaluation report and suggestions for a user, wherein the immersion effect is evaluated as being at a first level when the immersion index Eix0≥0.8, the immersion effect is evaluated as being at a second level when 0.4≤Ei<0.8, and the immersion effect is evaluated as being at a third level when Ei<0.4.