Touch detection method and related optical touch system

A touch detection method for an optical touch system, the touch detection method comprising:

• controlling a light pen having touch operation capability and a plurality of light sources to emit light with time division;
• using a light-reflecting element to reflect light emitted by the plurality of light sources and capturing a first image during a period when the plurality of light sources are emitting light;
• capturing a second image during a period when the light pen is emitting light;
• and
• computing a first location in which the light pen is located on a touch screen and a second location in which the light-reflecting element is located on the touch screen according to the first image and the second image.

An optical touch system, comprising:

• a touch screen;
• a plurality of light sources, for periodically emitting light;
• a light pen, for performing touch operations on the touch screen and continuously emitting light;
• a light-reflecting element, operated on the touch screen and reflecting light emitted by the plurality of light sources when the plurality of light sources are emitting light;
• a plurality of lenses, for capturing a first image during a period when the plurality of light sources are not emitting light and capturing a second image during a period when the plurality of light sources are emitting light;
• and
• a processing unit, comprising:
• a control unit, for controlling the plurality of light sources to periodically emit light;
• a comparison unit, for comparing the first image and the second image to generate a comparison result;
• and
• a determination unit, for determining locations of the light pen and the light-reflecting element according to the comparison result;
• wherein the first image comprises an image of the light pen, and the second image comprises an image of the light-reflecting element and the image of the light pen.

A touch detection method, for an optical touch system, the touch detection method comprising:

• controlling a plurality of light sources to periodically emit light and controlling a light pen having touch operation capability to continuously emit light;
• using a light-reflecting element to reflect light emitted by the plurality of light sources when the plurality of light sources are emitting light;
• capturing a first image during a period when the plurality of light sources are not emitting light, and capturing a second image during a period when the plurality of light sources are emitting light;
• and
• comparing the first image and the second image to generate a comparison result, and determining locations of the light pen and the light-reflecting element according to the comparison result;
• wherein the first image comprises an image of the light pen, and the second image comprises an image of the light-reflecting element and the image of the light pen.