In a method for modeling a darkfield candidate image at a sensor, a plurality of darkfield images of the sensor is captured, wherein each darkfield image of the plurality of darkfield images is associated with a different operational condition of the sensor. An operational condition of the sensor is determined. A darkfield candidate image comprising a combination of the plurality of darkfield images is modeled based at least in part on the operational condition of the sensor, wherein a contribution of each darkfield image of the plurality of darkfield images is dependent on the operational condition.