The aim of this paper is to introduce the use of sparse multistatic arrays to reduce the number of elements in novel portable and muti-view millimiter-wave scanners. Thus, the complexity of these novel scanners is significantly reduced. Furthermore, sparsity is expected to enable embedding a conventional optical camera sensor inside the aperture of the scanner allowing a reduction of the scanner size. This camera sensor is used to build a complementary 3-D optical model as well as to estimate the millimeter-wave scanner position so that the imaging merging techniques can be applied. The approach is validated for concealed weapon detection by means of simulation as well as measurements, in which the scanner aperture is emulated by raster scan, showing a performance comparable to the case of dense arrays.