Micro-focus field emission x-ray sources and related methods are provided. A parallel imaging reconstruction technique is applied to the first incomplete k-space data to determine a plurality of second k-space lines not included in the first incomplete k-space data set, thereby yielding a second incomplete k-space data set. The model generates residuals by calculating the difference between the actual values and the predicted values for each member of the set. The threads include at least one load instruction that causes the instruction execution circuitry to retrieve data from the data cache. The reference camera, the tracking camera, and the presence-sensing devices are integrated by a controller. When a starter switch, which turns the flow of current from the power source to the first current system on or off, is turned on and electricity flows to the first current system, the delay unit delays the current flowing from the first current system to the second current system.