Patent ID: 8497841

Claim:
A method, comprising: providing a plane of light above a working area, the working area including indicia of a virtual keyboard having a plurality of keys; capturing images of the working area with an image capture device positioned above the plane of light, the images including rows of pixels and columns of pixels; detecting a selected key of the plurality of keys, the detecting of the selected key including: detecting an object adjacent to the selected key by analyzing each of the captured images for variations in light intensity, the detecting of the object including: generating a first histogram by summing the light intensity in each of a first number of columns; determining a second number of columns corresponding to a portion of the first histogram that is above a first threshold light intensity value; generating a second histogram by summing the light intensity in each of a first number of rows in the second number of columns; determining a second number of rows corresponding to a portion of the second histogram that is above a second threshold light intensity value; determining an identification of the selected key from the light intensity corresponding to the pixels in the second number of rows and the second number of columns; and outputting the identification of the selected key to a host device.