Disclosed herein is a method comprising: generating multiple radiation beams respectively from multiple locations toward an object and an image sensor, wherein the image sensor comprises an array of multiple active areas, and gaps among the multiple active areas, and capturing multiple partial images of the object with the image sensor using respectively radiations of the multiple radiation beams that have passed through and interacted with the object, wherein each point of the object is captured in at least one partial image of the multiple partial images.