Patent ID: 8228569

Claim:
An image acquiring apparatus, comprising: an image sensor, for outputting a plurality of first analog image signals corresponding to a plurality of pixels; an analog-to-digital converter (ADC), for converting the plurality of first analog image signals to a plurality of digital image signals; a digital-to-analog converter (DAC), coupled to the ADC, for converting the plurality of digital image signals to a plurality of second analog image signals, wherein each of which has an actual voltage value; a comparing unit, coupled to the DAC, for respectively comparing the actual voltage values of the plurality of second analog image signals with a reference voltage value so as to generate a plurality of corresponding comparing results; a counting unit, coupled to the comparing unit, for adjusting a counting value according to each of the comparing results; and a control unit, coupled to the counting unit, for determining whether to stop a scanning operation of the image acquiring apparatus or not according to the counting value.