The paper discusses a computational ghost-imaging technique that uses only a single-pixel detector, which is a significant advancement in the field of ghost imaging. Ghost imaging is a method for acquiring object information through photocurrent correlation measurements. The authors describe a setup where a continuous-wave (CW) laser beam is transmitted through a spatial light modulator (SLM) to create a coherent field that interacts with the object. This field is then collected by a single-pixel detector, and the intensity fluctuations are pre-computed using diffraction theory. The pre-computed intensity fluctuations are correlated with the detector's photocurrent to form a background-free ghost image with high spatial resolution. This approach eliminates the need for a high-resolution detector and allows for 3D sectioning of the object's reflectance. The paper also highlights the classical nature of ghost-image formation, as the computational ghost image cannot be explained by nonlocal two-photon interference, which has been argued in some recent works. The technique is supported by theoretical analysis and experimental demonstrations, and it offers a flexible and efficient method for ghost imaging.The paper discusses a computational ghost-imaging technique that uses only a single-pixel detector, which is a significant advancement in the field of ghost imaging. Ghost imaging is a method for acquiring object information through photocurrent correlation measurements. The authors describe a setup where a continuous-wave (CW) laser beam is transmitted through a spatial light modulator (SLM) to create a coherent field that interacts with the object. This field is then collected by a single-pixel detector, and the intensity fluctuations are pre-computed using diffraction theory. The pre-computed intensity fluctuations are correlated with the detector's photocurrent to form a background-free ghost image with high spatial resolution. This approach eliminates the need for a high-resolution detector and allows for 3D sectioning of the object's reflectance. The paper also highlights the classical nature of ghost-image formation, as the computational ghost image cannot be explained by nonlocal two-photon interference, which has been argued in some recent works. The technique is supported by theoretical analysis and experimental demonstrations, and it offers a flexible and efficient method for ghost imaging.