Multi-point touch multimedia spherical screen demonstration instrument and multi-point touch method thereof

The invention discloses a multi-point touch multimedia spherical screen demonstration instrument and a multi-point touch method thereof. A three-dimensional space model corresponding to a spherical screen demonstration instrument is pre-memorized and comprises a virtual sphere of a three-dimensional coordinate system of the spherical screen demonstration instrument and the corresponding relation of a two-dimensional cake coordinate system, wherein a virtual sphere coordinate system of the three-dimensional coordinate system and the two-dimensional cake coordinate system are dynamically switched through a rectangular coordinate system. An image corresponding to the two-dimensional cake coordinate system is projected onto a spherical screen of the spherical screen demonstration instrument through a projector and a fish-eye lens inside the spherical screen demonstration instrument. Touch actions are detected on the spherical screen surface of the spherical screen demonstration instrument, and the types of the touch actions are judged. According to the three-dimensional space model of the spherical screen demonstration instrument and the types of the touch actions, the actions of the spherical screen demonstration instrument are controlled. The three-dimensional space model is established for the spherical screen demonstration instrument by means of the method, and the control to the spherical screen demonstration instrument is achieved based on the three-dimensional space model.