Lateral migration radiography (LMR), a form of Compton backscatter radiography, is applied to the detection and identification of landmines. The LMR system consists of two inner uncollimated detectors positioned to optimally detect first scattered photons and two outer collimated detectors designed to detect primarily photons that have had two or more scatterings. The difference between the collimated and uncollimated detector response to both the landmines themselves and the different types of landmine image masking phenomena, form the basis of the image enhancement and landmine identification procedures. Surface feature information is the primary component of the uncollimated detector response. The collimated detector signal contains information about the surface features as well as the buried objects. The principles of the detection system have been shown in previous work and now the focus has shifted to the preparation for field tests and the associated problems. One of the expected events that the detector system will encounter is the variation of detector height with respect to the ground. This is caused by irregularities in the surface as will as oscillations of the detection vehicle. The collimated detectors and the uncollimated detector react differently to height variations. When the detector height increases the uncollimated detector response will be reduced due to the decrease in solid angle. Although the collimated detector will also be affected by the change in solid angle the dominate reaction is the loss of collimation causing the collimated detectors signal to increase. When the detector height decreases the opposite responses are observed. By using the information from both detector systems, the effects of the detector height variation can be removed.