Patent ID: 8907926

Claim:
A method for calibrating accuracy of an optical touch monitor, wherein the optical touch monitor has a first lens and a second lens, the first lens and the second lens are disposed at a same side of the optical touch monitor and faced towards another side of the optical touch monitor, the method comprising: touching one of a plurality of control points (CPs) on the optical touch monitor by using a touch object; respectively capturing a first image and a second image by using the first lens and the second lens; respectively detecting a first position and a second position of the touch object in the first image and the second image; moving the touch object to touch the other CPs on the optical touch monitor, and repeating foregoing steps to obtain the first position and the second position of the touch object in the first image and the second image when the touch object touches each of the CPs; and substituting the first position and the second position of the touch object obtained when the touch object touches each of the CPs into a non-linear transformation function to calculate a weight matrix for system transformation, wherein the non-linear transformation function comprises a affine transform function and a radial basis function (RBF); and when the touch object touches a touch point on the optical touch monitor, detecting a touch position of the touch object on the optical touch monitor, and transforming the touch position into screen coordinates of the optical touch monitor by using the weight matrix and the non-linear transformation function, wherein the weight matrix is expressed as: W=L −1 Y, Y is a spatial position matrix, and L is a combination matrix of a radial basis matrix and an image position matrix, wherein the combination matrix is expressed as: L = [ K | P P T | O ] , K is the radial basis matrix and expressed as: K = [ 0 U ⁡ ( r 12 ) … U ⁡ ( r 1 ⁢ n ) U ⁡ ( r 21 ) 0 … U ⁡ ( r 2 ⁢ n ) ⋮ ⋮ ⋱ ⋮ U ⁡ ( r n ⁢ ⁢ 1 ) U ⁡ ( r n ⁢ ⁢ 2 ) … 0 ] , r is a distance between every two of the CPs, and U is the RBF, P is an image position matrix and expressed as: P = [ 1 u 1 v 1 1 u 2 v 2 ⋮ ⋮ ⋮ 1 u n v n ] , u is the x-value of the touch object in the second image, and v is the x-value of the touch object in the first image, P T is a spatial position transpose matrix, and O is a zero matrix.