The present application further describes a turbine blade that may include an airfoil, a tip shroud that is positioned at one end of the turbine blade, a coolant passage that extends through the airfoil to the tip shroud, and a continuous cooling cavity that is defined within the tip shroud and that is in fluid communication with the coolant passage. In each current row of pixels with associated values, pixels are selected which satisfy a selection rule based on the values for the pixels in the current row with associated values and on the values from the previous andor the next row with associated values, and segments of pixels are detected. The QA system selects a subset of candidate answer sources, from a group of candidate answer sources, based on a ranked listing of candidate answer sources.