aliasing artifact

aliasing artifact

In MRI, superimposition of a tissue image from outside the field of view on the opposite side of the desired image, usually in the phase-encode direction, due to an inadequate number of phase-encoding measurements for the size of the field of view. Inadequate sampling in the frequency-encoding direction can also cause wraparound or aliasing, but this finding is less common with modern MR equipment.
Synonym(s): wraparound artifact
[L. alias, otherwise, fr. alius, other]
References in periodicals archive ?
However these methods suffer the limitations such as low signal-to-noise ratio (SNR) and aliasing artifacts for high sampling factors.
The beating heart caused aliasing artifacts in the first-phase encode direction (superior-inferior).
The aliasing artifacts are greatly reduced in the areas indicated by the arrows by TV, TGV, and NN.
For this reason, in actual experiments, model error is also exaggerated by IV method so that aliasing artifacts are more obvious than that generated by least squares method.
For k-space, because noise-related errors are generally decided by signals at high frequency region (outer region) and generation of aliasing artifacts is usually dependent on signals at low frequency region (central region), in order to avoid aliasing artifacts' deterioration by IV method mentioned above, we choose signals between high frequency and low frequency regions for constructing instruments to achieve a compromise between removing noise and suppressing aliasing artifacts.
The enhanced control of tone also helps avoiding blending or aliasing artifacts.
For example, aliasing artifacts or streaks appear as dark lines that radiate away from sharp corners.
However, aliasing artifacts may occur in these sampling methods.
Additional enhanced functionality within EDIUS 7 includes an improved 4K workflow, support for the latest file formats (including XAVC/XAVC S and AVC-Ultra), automatic program update checking, updated MPEG and H.264/AVC performance, faster handling of large quantities of still image files (JPG, TGA, DPX, and others), and a Gaussian blur filter to apply better quality blurring and to prevent Moire pattern aliasing artifacts.