Lift detection method for mouse and apparatus thereof

A method for determining when an optical mouse is in a lifted condition above a surface, the optical mouse comprising a pixel array and a light source, the method comprising:

• determining a surface quality value Psqual and determining a pixel average value Pavg of pixel values of the pixel array;
• comparing Psqual with a value PliftedsqualTH which is a threshold of the optical mouse being in a lifted condition;
• comparing Pavg with a value PliftedaccavgTH which is a threshold of average accumulated pixel values of the pixel array when the optical mouse is in a lifted condition;
• when Psqual is less than PliftedsqualTH and Pavg is less than PliftedaccavgTH, directly determining the optical mouse to be in a lifted condition;
• and when Psqual is equal to or greater than PliftedsqualTH and Pavg is equal to or greater than PliftedaccavgTH, accumulating the pixel values of the pixel array;
• comprising:
• accumulating pixel values of a first column of the pixel array, the first column being closest to the light source;
• accumulating pixel values of a second column of the pixel array, the second column being different from the first column;
• comparing the accumulated pixel values of the first column with the accumulated pixel values of the second column;
• and when a difference between the accumulated pixel values of the first column and the accumulated pixel values of the second column is greater than a threshold value, determining the optical mouse to be in a lifted condition.