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12 April 2005 Effect of grayscale resolution on the performance of lung nodule detection on a softcopy display
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A four-alternative forced-choice experiment was carried out to examine the effect of 8-bit versus 10-bit grayscale resolution on the detection of subtle lung nodules on a medical grayscale liquid crystal display (LCD). Sets of four independent backgrounds from each of three regions were derived from a very low-noise X-ray acquisition of a chest-phantom with an amorphous selenium radiographic detector. Simulated nodules of fixed diameter (10 mm) and varying contrast were digitally added to the centers of selected background images. Subsequently, multifrequency image processing was performed to enhance the image structures, followed by a tonescaling procedure that resulted in pixel values being specified as p-values, according to DICOM Part 14: The Grayscale Display Function. To investigate the effect that grayscale resolution may have upon softcopy detectability, each set of four images in the experiment was quantized to both 8-bit and 10-bit resolution. The resulting images were displayed on a DICOM-calibrated LCD display supporting up to 10 bits of grayscale input. Twenty observers with imaging expertise performed the nodule detection task for which the signal and location were known exactly. Results from all readers, chest regions, and backgrounds were pooled, and statistical significance between fractions of correct responses between 8-bit and 10-bit resolution was tested. Experimental results do not demonstrate a statistically significant difference in the fraction of correct answers between these two input grayscale resolutions.
© (2005) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
W. James Sehnert, Brian W. Keelan, and Karin Toepfer "Effect of grayscale resolution on the performance of lung nodule detection on a softcopy display", Proc. SPIE 5744, Medical Imaging 2005: Visualization, Image-Guided Procedures, and Display, (12 April 2005);

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