Patent ID: 7728893

Claim:
A method of reading pixel signals from an image sensor having a pixel cell array with a number of pixel cells two-dimensionally arranged in an imaging device for capturing images of an imaging area within which a light-emitter producing an information light whose frequency is higher than the normal frame frequency is present and for collecting both image information of the imaging area and identification information transmitted by the information light, the method comprising: classifying all the pixel cells into two types: one or more pixel cells receiving the information light, which are called signal-receiving pixel cells, and the other pixel cells, which are called imaging pixel cells; dividing a first period of time for sequentially reading the pixel signals from the imaging pixel cells for constructing one frame of image into a plurality of fractional time sections, and determining a readout procedure so that a second period of time for reading the pixel signal from the signal-receiving pixel cell is inserted between each neighboring pair of the time sections; and reading the pixel signal from the same signal-receiving pixel cell more than one time during one round of readout of the pixel signals from all the imaging pixel cells through all the time sections.