Image detection
By image detection we mean the recording of the surface or spatial distribution of certain physical parameters of the displayed scene and the conversion of this image function into another form of signal (e.g. an electrical signal), which has more favorable properties for further processing, display and storage. Image detectors (sensors) ensure the recording and transformation of the image signal . It is usually a two-dimensional array of a large number of suitable detection elements (transducers), which, in addition to the values of the displayed parameters of the scene, also provide spatial information about the exact location of the signal. Each detection element of the sensor records one image point (pixel) of the resulting image. For tomografic methods is the result of the detection of the so-called voxel (from the English Volumetric Pixel) – volumetric element of the image. In medicine, there are a number of commonly imaged scene parameters that can be recorded in a variety of ways.
| Method | Physical parameter | Image detector |
|---|---|---|
| X-ray a CT imaging | X-ray attenuation | flat panel, photographic film, scintillation detectors |
| ultrasound imaging | reflectivity, attenuation | piezoelectric crystals |
| magnetic resonance | quantum behavior of atomic nuclei | coils |
| nuclear medicine (PET, SPECT, gammagraphy) | activity of radionuclides | scintillation detectors, flat panel |
| thermography | surface temperature (infrared radiation) | semiconductor detectors, liquid crystals |
| elastography | Young's modulus of elasticity | piezoelectric crystals, coils |
| electrodiagnostic mapping | electrical properties | electrode array |
| magnetodiagnostic mapping | magnetic properties | array od coils |
| microscopy, endoscopy | attenuation, reflection or scattering of electromagnetic radiation (UV, IR, VIS, microwaves) | semiconductor detectors |
| electric impedance tomography (EIT) | electric conductivity, permittivity | electrode array |
Links[edit | edit source]
Used literature[edit | edit source]
- SEDLÁŘ, Martin – STAFFA, Erik – MORNSTEIN, Vojtěch. Zobrazovací metody využívající neionizující záření [online]. Brno : Institute of biophysics, Faculty of Medicine, Masaryk University in Brno, 2013, Available from <http://www.med.muni.cz/biofyz/zobrazovacimetody/files/zobrazovaci_metody.pdf>.
