System and method of distinguishing multiple touch points applied to an optical touch system

A system of distinguishing multiple touch points, comprising:

• a panel, for indicating a first touch point and a second touch point thereon;
• a camera unit, for capturing an image relative to the first touch point and the second touch point, the image having a first dark area and a second dark area corresponding to the first touch point and the second touch point respectively;
• a data processing module, coupled to the panel and the camera unit;
• and
• a store unit, coupled to the data processing module and for storing area information corresponding to the first touch point and the second touch point respectively, a program being stored in the store unit and being capable of being accessed and executed by the data processing module, the program comprising:
• a first instruction, for judging whether the first dark area and the second dark area are a first single dark area currently;
• a second instruction, for if the judging in the first instruction is YES, judging whether the first dark area and the second dark area are a second single dark area at a previous time;
• a third instruction, for if the judging in the second instruction is YES, determining a position of the first dark area and a position of the second dark area according to a union dark area width of the first single dark area and a union dark area width of the second single dark area;
• and
• a fourth instruction, for determining coordinates of the first touch point and the second touch point according to the position of the first dark area and the position of the second dark area,
• if the judging in the second instruction is NO, determining the position of the first dark area by shifting by a previously-stored first dark area width along a first direction from a first boundary of the first single dark area, and determining the position of the second dark area by shifting by a previously-stored second dark area width along a second direction from a second boundary of the first single dark area.

A non-transitory storage medium storing a program therein, the program being capable of being accessed by a touch system which comprises a panel for indicating a first touch point and a second touch point thereon, a store unit for storing area information of the first touch point and the second touch point respectively and for storing a first dark area width and a second dark area width, and a camera unit for capturing an image relative to the first touch point and the second touch point, the image having a first dark area and a second dark area corresponding to the first touch point and the second touch point respectively, the program making the touch system execute the following steps of:

• (a0) judging whether an instruction is executed by the touch system;
• (a) if the judging in the step (a0) is YES, judging whether the first dark area and the second dark area are a first single dark area currently;
• (b) if the judging in the step (a) is YES, judging whether the first dark area and the second dark area are a second single dark area at a previous time;
• (c) if the judging in the step (b) is YES, determining a position of the first dark area and a position of the second dark area according to a union dark area width of the first single dark area and a union dark area width of the second single dark area;
• (d) determining coordinates of the first touch point and the second touch point according to the position of the first dark area and the position of the second dark area,
• wherein the step (c) comprises the following sub-steps of:
• (c1) if the union dark area width of the first single dark area is shorter than the union dark area width of the second single dark area, determining the position of the first dark area by shifting by the first dark area width along a first direction from a first boundary of the first single dark area, and determining the position of the second dark area by shifting by the second dark area width along a second direction from a second boundary of the first single dark area;
• (c2) if the union dark area width of the first single dark area is equal to the union dark area width of the second single dark area, determining the position of the second dark area according to a movement parameter of the second touch point;
• and
• (c3) if the union dark area width of the first single dark area is longer than the union dark area width of the second single dark area, determining the position of the second dark area by shifting by the second dark area width along the first direction from the first boundary of the first single dark area, and determining the position of the first dark area by shifting by the first dark area width along the second direction from the second boundary of the first single dark area;
• (e) if the judging in the step (a) is NO, judging whether the first dark area and the second dark area are a third single dark area at the previous time;
• and
• (f) if the judging in the step (e) is YES, determining the coordinates of the first touch point and the second touch point by comparing current area information of the first touch point and the second touch point with the area information of the first touch point and the second touch point stored in the store unit.