A method, comprising: receiving, by processing circuitry of a computer configured to render images of objects, depth image data representing a plurality of depth images (134... 134; 314, 324) of an object, each of the plurality of depth images (134... 134; 314, 324) being a depth image of the object captured from a respective viewpoint, the depth image representing a map of distances between an image capture device and the object; receiving viewpoint data representing a target viewpoint of an image of the object, the target viewpoint being different from the respective viewpoint from which each of the plurality of depth images (134... 134) are captured, the image including a plurality of pixels; generating ray data representing a plurality of rays toward the image, each of the plurality of rays corresponding to a respective pixel of the plurality of pixels of the image and the plurality of rays emanating from the target viewpoint to the plurality of pixels of the image; for each of the plurality of rays: generating signed distance value, SDV, data representing a plurality of SDVs at each of a plurality of locations along that ray, each of the plurality of SDVs at each of the plurality of locations along that ray corresponding to a respective depth image (314, 324) of the plurality of depth images (134... 134; 314, 324); performing an aggregation operation on the SDV data at each of the plurality of locations along that ray to produce aggregated SDV data along that ray representing an aggregated SDV at each of the plurality of locations along the ray; and determining a location along that ray where the aggregated SDV satisfies a specified condition by performing a root-finding operation on the aggregated SDV along the ray to produce a root location; and generating a target depth image of the object captured from the perspective of the target viewpoint based on the locations along the plurality of rays for which the respective aggregated SDV for that ray satisfies the specified condition. receiving, by processing circuitry of a computer configured to render images of objects, depth image data representing a plurality of depth images (134... 134; 314, 324) of an object, each of the plurality of depth images (134... 134; 314, 324) being a depth image of the object captured from a respective viewpoint, the depth image representing a map of distances between an image capture device and the object; receiving viewpoint data representing a target viewpoint of an image of the object, the target viewpoint being different from the respective viewpoint from which each of the plurality of depth images (134... 134) are captured, the image including a plurality of pixels; generating ray data representing a plurality of rays toward the image, each of the plurality of rays corresponding to a respective pixel of the plurality of pixels of the image and the plurality of rays emanating from the target viewpoint to the plurality of pixels of the image; for each of the plurality of rays: generating signed distance value, SDV, data representing a plurality of SDVs at each of a plurality of locations along that ray, each of the plurality of SDVs at each of the plurality of locations along that ray corresponding to a respective depth image (314, 324) of the plurality of depth images (134... 134; 314, 324); performing an aggregation operation on the SDV data at each of the plurality of locations along that ray to produce aggregated SDV data along that ray representing an aggregated SDV at each of the plurality of locations along the ray; and determining a location along that ray where the aggregated SDV satisfies a specified condition by performing a root-finding operation on the aggregated SDV along the ray to produce a root location; and generating a target depth image of the object captured from the perspective of the target viewpoint based on the locations along the plurality of rays for which the respective aggregated SDV for that ray satisfies the specified condition. generating signed distance value, SDV, data representing a plurality of SDVs at each of a plurality of locations along that ray, each of the plurality of SDVs at each of the plurality of locations along that ray corresponding to a respective depth image (314, 324) of the plurality of depth images (134... 134; 314, 324); performing an aggregation operation on the SDV data at each of the plurality of locations along that ray to produce aggregated SDV data along that ray representing an aggregated SDV at each of the plurality of locations along the ray; and determining a location along that ray where the aggregated SDV satisfies a specified condition by performing a root-finding operation on the aggregated SDV along the ray to produce a root location; and generating a target depth image of the object captured from the perspective of the target viewpoint based on the locations along the plurality of rays for which the respective aggregated SDV for that ray satisfies the specified condition.