The invention relates to detectors for radiological imaging, and more
particularly the X-ray matrix detectors, produced in the form of a CMOS
technology pixel matrix, associated with a structure for converting
X-rays into electrons. Each pixel comprises a reading circuit comprising
on the one hand a comparator (COMP1) switching over each time a charge
increment arrives resulting from the integration of a charge current
generated by the lighting and on the other hand a counting circuit (CPT1,
CPT2) for counting the number of switchovers of the comparator. The
circuit for reading each pixel comprises a circuit (CMC) for analyzing
the rate of the switchovers of the comparator, this analysis circuit
acting on the counting circuit to modify its operation according to the
result of the rate analysis. For example, the analysis circuit switches
the counting pulses to one counter (CPT1) or another counter (CPT2)
depending on the result of the analysis. Applicable in particular to
bi-energy radiology and X-photon impact spectrometry analysis.