unsharpness

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unsharpness

A quantitative measure of the loss of edge detail due to geometric properties of the object and imaging system and not to image noise or X-ray scatter. Unsharpness is usually expressed as the width of the band of changing density or brightness arising from a sudden change in the intensity of the radiation incident on the film or fluorescent screen.

Factors contributing to image unsharpness
Geometric unsharpness, movement unsharpness, absorption unsharpness, image receptor unsharpness and parallax unsharpness. It is known from observation that the total unsharpness is not the direct sum of the contributing factors; rather, it is dominated by the unsharpness of the largest individual factor.

unsharpness

lack of detail in an x-ray picture.
References in periodicals archive ?
Ensuing chapters discuss techniques such as multimodality imaging, nonlinear unsharp masking, wavelet-based feature extraction, fractal analysis, image reconstruction, and other interpolative procedures in the detection of breast, skin, and prostate cancers.
The resulting image was processed by applying an unsharp mask to bring out fine details in the tail.
The sharpening techniques utilized are - Low Pass filter (utilized by NASA), UnSharp Mask, and Threshold.
The muscle architecture was altered, and there was blurring of the margins between muscle bundles and an unsharp appearance to the contents of each muscle bundle.
In a study comparing CT findings in these two infections in 58 immunocompromised HIV-negative patients, small and centrilobular nodules, unsharp demarcation of the ground-glass infiltrates and consolidation favoured CMV pneumonia, while an apical distribution and the occurrence of a mosaic pattern suggested PCP.
This choice of features have been made for two reasons: on one hand Haar features are generally applicable to any kind of probe and, since we have to consider unsharp representation of any object when operating on heavily blurred images, features of, e.
Fuzzy logic deals with fuzzy sets that classify using unsharp boundaries.
In digital radiography, preprocessing (to correct for system irregularities such as dead pixels or dark noise), processing (manipulation of raw data such as unsharp mask, histogram sliding and stretching), and postprocessing (manipulation of the final appearance of the radiograph by the end user) of digital radiographs are used.
His darkroom techniques include dodging, burning, multiple filtration, flashing, bleaching, unsharp masking - anything it takes to make the image come alive.
The program uses a simple, elegant and yet powerful variation of the common unsharp mask, where the procedure is to defocus and subtract one image of a stereo pair from the other, rather than defocusing and subtracting an image from itself.
By this, we mean applying a threshold to the difference between the image obtained after the first stage (involving the stretch of the document's contrast) and a leveled version of it, obtained using one of the following three methods: Gaussian unsharp (Dobrescu et al.