Fourier telescopy can realize high resolution imaging to remote, small and dim target by using laser as the light source. The signal-to-noise ratio of imaging system is easy to improve by increasing the area of receiver. However, numerical simulation shows that the reconstruction images sometimes has a virtual phenomenon. It reduces the quality of reconstruction images, and even cannot have a resolution to the imaging target. Based on Fourier telescopy imaging principle, using T type transmitting array, the reason of forming virtual images is indicated by mathematical deduction. The spatial frequency error between the actual getting and setting would be produced when the laser beams scan the x or y axis with pitch error. The error would cause the random phase influence when calculating the single Fourier frequency of target by using phase closure on the axis and quadrant scan. Using integrated spatial frequency of transmitter array to reconstruct the image of target would cause a virtual phenomenon. By contrasting reconstruction images it is found that the image quality is reduced seriously, even the virtual phenomenon appears when the transmitting system is axially scanned with pitch error, and it decreases slightly on quadrant scan. In the present paper, we consider the reason of the phase closure of quadrant of T type transmitting array relies on axial frequency. At the same pitch error, different scan methods would cause different reconstruction images. The directions of virtual images are the same within the axial error. The computer simulation confirms the validity of the above analysis by three different modes of transmitter array through using the next field experiment parameters.