A single-pixel camera can be represented using complex-amplitude. The complex-amplitude representation of input signals and output signals enables us to perform complex-amplitude imaging of an object, particularly profilometry with reflectance measurements or quantitative phase imaging with transmittance measurements. The complex-amplitude representation of optical coding masks and the coherent addition that is performed by interference can directly represent Hadamard patterns having positive and negative values. Furthermore, the residual area of the mask can be used for a reference beam with phase shifting. Such a complex-amplitude imaging system with a single-beam line structure is highly stabile against external disturbances.