Automobile scanning system

An apparatus for searching an automobile for security threats, comprising:

• x-ray generating means for penetrating said automobile with x-ray radiation;
• switching filter means for changing said x-ray radiation between a low-energy spectrum and
• a high-energy spectrum, wherein said low-energy spectrum is substantially determined by the k-edge energy of a high atomic number element;
• x-ray detector means for converting the x-ray radiation that penetrates said automobile into a digitally represented signal;
• computer means for converting said digitally represented signal into a steel suppressed digital image of said automobile using logarithmic subtraction.

An apparatus for searching an automobile for security threats, comprising:

• x-ray generating means for penetrating said automobile with x-ray radiation;
• switching filter means for changing said x-ray radiation between a low-energy spectrum and a high-energy spectrum, the switching filter means comprises rotating filter means, said rotating filter means comprising a low-energy filter material and a high-energy filter material, the low-energy filter material is selected from the group consisting of platinum, gold, mercury, thallium, lead, bismuth, and thorium;
• wherein said low-energy spectrum is substantially determined by the k-edge energy of a high atomic number element;
• x-ray detector means for converting the x-ray radiation that penetrates said automobile into a digitally represented signal;
• computer means for converting said digitally represented signal into a steel suppressed digital image of said automobile using logarithmic subtraction.