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A digital imaging system has a large dynamic range. What does this mean?
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Digital Imaging
Advanced Mod, digital imaging
| Question | Answer |
|---|---|
| - the beam that contains useful or diagnostic information | remnant beam |
| A digital imaging system has a large dynamic range. What does this mean? | the digital image receptor responds to a wide range of exposure values to create diagnostic images |
| Which types of system is more forgiving on technique: digital or analog? | Digital |
| What converts the remnant xray beam exiting the patient into light? | intenssifying screen |
| What is considered the recording device? | The film |
| The image created on the film directly after exposure that is not yet visible to the human eye is known as what? | The latent image |
| What is the name of the image produced then the latent image is converted? | manifest image |
| The process of assigning numberic values to the signal is called? | quantization |
| Quantization determines what part of the image? | Gray levels |
| What two symbols make up binary language? | 0 or 1 |
| What is a bit? | short for binary digit and is the numbers used in binary language |
| What is a string of 8 bits called? | byte |
| What determines the number of gray levels? | bit depth |
| How many shades of gray are available if there are 6 bits? | 64 |
| As pixel size used to produce an image decreases, what happens to recorded detail? | increases |
| What are the 4 types of digital image receptors? | Photostimulable phosphor (PSP) flat panel with thin film transistor (TFT)charged coupled device (CCD) complementary metal oxide semiconductor (CMOS) |
| A term used to refer to the ability of certain materials to respond to excitation and give off light | Scintillation |
| What kind of light is used to scan the receptor plate to extract the image data? | red laser light |
| - complex circuit device that collects electrons emitted from either amorphous selenium or amorphous silicon? | thin film transistor |
| Information patterns that dont add to the diagnostic information within the image are referred to as what? | Noise |
| Which type of receptors resond to lower light levels from a scintillator than other types of receptors, making them suitable for low-dose imaging? | CCD, charger coupling devices |
| What is DQE? | detective quantum efficiency, a measure of an image receptor's ability to create an output signal that accurately represents te input signal of the xray beam that exits a patient |
| Lower frequency equates to what kind of pixel size? and spatial resolution? | larger pixel size, lower spatial resolution |
| If you want higher resolution, what kind of dector needs to be used? | flat-panel with smaller del's |
| What determines the level of spatial resolution for an image receptor? | Nyquist frequency |
| According to the Nyquist theorem, given spatial frequency or resolution, what must you do ? | sample the signal at twice the desired sampling frequency |
| What type of receptor can produce an image that appears acceptable on a display monitor, but was produced at 50% underexposure or up to 100% overexposure? | digital receptor |
| What two visual ques determine whether the exposure values are incorrect? | Noise and loss of image contrast |
| What is the visual cue for underexposued image? | Noise |
| What is the visual cue for overexposure? | loss of image contrast |
| If the input phosphor size is reduced, what happens to the output phosphor? | remains the same and the image is magnified |
Created by:
erikasmith28
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