Semiconductor-based biosensors for base calling

A device for base calling, comprising:

• a receptacle configured to hold a biosensor, the biosensor having
• a sample surface that holds a plurality of clusters during a sequence of sampling events,
• an array of sensors, where each sensor in the array senses information from one or more clusters disposed in corresponding pixel areas of the sample surface to generate a pixel signal in a sampling event, the array configured to generate a plurality of sequences of pixel signals, the array having a number N of active sensors, the sensors in the array disposed relative to the sample surface to generate respective pixel signals during the sequence of sampling events from the number N of corresponding pixel areas of the sample surface to produce the plurality of sequences of pixel signals, and
• a communication port which outputs the plurality of sequences of pixel signals;
• and
• a signal processor coupled to the receptacle, and configured to receive and to process the plurality of sequences of pixel signals to classify results of the sequence of sampling events on clusters in the plurality of clusters, wherein information sensed from at least two clusters in the corresponding pixel area is additively combined and represented in a common pixel signal for each sampling event in at least one sequence of pixel signals in the plurality of sequences of pixel signals, and including using the plurality of sequences of pixel signals to classify results of the sequence of sampling events on a number N+M of clusters in the plurality of clusters from the number N of active sensors, where M is a positive integer.