Touch screen display system and a method for controlling a touch screen display system

A touch screen display system, comprising:

• at least two touch screen display apparatuses, respectively comprising a first touch screen and a second touch screen, wherein one of the at least two touch screen display apparatuses senses the first touch screen in a first time period, and another one of the at least two touch screen display apparatuses senses the second touch screen in a second time period;
• and
• a host apparatus, electrically connected to the at least two touch screen display apparatuses, and adapted to determine a touch location of a first touch object on the first touch screen or a touch location of a second touch object on the second touch screen, wherein the at least two touch screen display apparatuses comprise a first image capturing apparatus and a second image capturing apparatus, the first image capturing apparatus senses the first touch object on the first touch screen in the first time period, the second image apparatus senses the second touch object on the second touch screen in the second time period,
• wherein the host apparatus further controls the at least two touch screen display apparatuses to respectively display a plurality of test patterns on the first touch screen and the second touch screen for touch screen calibration in a manner of time division,
• wherein the test patterns comprise at least a first pair of test patterns having a gray scale compensation property, using at least two gray scales including white and black.