Digital Subtraction


A set of four test objects, the DSF set is supplementary to the SFS set of test objects and checks those parameters which are particularly relevant to DSF imaging. After mask images have been obtained the image content is changed by the manipulation of various plates.

The kit consists of:

  • TO J3
    Log/Linear subtraction ADC and DAC operation: 10 step wedge with linear transmission profile, 9 step wedge with logarithmic transmission profile. Operating headroom (highlight overload) 9 step wedge exceeding the peak reference level
  • TO Q3
    Dynamic range of imaging capability. Contains four quadrants of relative transmission 100%, 33%, 10%, 3.3%. Each quadrant contains 16 details, 8mm diameter, with contrast ranges 0.18 to 0.001. (Filter Plate plus Detail and Blank Plate).
  • TO 20*
    Threshold-contrast detail-detectability: 144 details (12 sizes x 12 contrasts), size range 11mm to 0.25mm. (Used with Blank Plate).
  • TO D3
    Systematic mis-registration artefacts: 91 details, 11mm diameter, contrasts 0.83, 0.46, 0.13.

* TO 20 is also available for ordering individually.  Other items are only available by ordering the full DSF set.

DSF Set of Phantoms
DSF Set of Phantoms