Purpose: To investigate why Image Intensity Uniformity (IIU) tests performed on commercial 3T MRI systems according to the ACR MR Accreditation Program (MRAP) instructions are subject to frequent failures. Method and Materials: The phantom scanning instructions for ACR MRAP tests specify that a ...
-亮度一致性 (Luma uniformity) -色度一致性(Chroma uniformity) 测试方法: 计算中心-四角以及中心-四边的亮度和色度误差值,采用dE2000 公式 3. 曝光和对比度 3.1 自动曝光测试 测试项目: -曝光误差(exposure error) -对比度 (contrast) 曝光误差测试方法: 在图像稳定时使用Imatest评估24色卡19~24色块,计算...
*all_intensity* integrated_intensity, mean, median, min, max, range, standard_deviation, standard_error, uniformity, skewness, kurtosis, hyperskewness, hyperflatness, mean_absolute_deviation, energy, root_mean_squared, entropy, mode, uniformity, p01, p10, p25, p75, p90, p99, interquartile_rang...
Does the demonstration page show any image-quality defects?Yes: If defects appear on the printed demonstration page the issue is PQ related. See Print-quality troubleshooting. No: If defects does not appear on the printed demonstration page the issue is CQ related. See Copy-quality ...
Finally, low photo-response non-uniformity (PRNU) of 1.0% at full-resolution and 0.8% with 2 × 2 binning was also demonstrated. The sensor also demonstrated high quantum efficiency (QE) in the visible wavelength region. The QE was measured with a National Institute of Standards and ...
at the MR hardware operational limit, including at high slew rates and high gradients, and because of the non-uniform B0 and B1 fields. In this section, we categories artefacts based on the hardware limitations, choice of acquisition sequence, sequence parameters, and scanner non-uniformity. ...
corresponding to the response time. Our photodiode remains the same photoresponse and a little decreased dark current when stored in dry air for 720 h without encapsulation (Supplementary Fig.S9), demonstrating good stability. And our devices exhibit good uniformity with the standard deviation of ...
Those image segmentation algorithms [1], [2], [3], [4] based on the assumption of intensity uniformity are not sufficient to discriminate the regions accurately. To solve the problem of illumination bias, many works [5], [6], [7], [8], [9] are proposed in different ways. These ...
With variable bin number, all parameters except uniformity showed CVs ≤ 15%. However, SNR and outlier options significantly limited the reliability of the inter-lesion RF ratios, with only one (6%) RF (entropy) having a CV ≤ 15% with variable SNR, and all RFs having a CV > 15% with...
Image retrieval was considered accurate if the automated algorithm returned the match section to within 3 mm of an expert-selected section; the retrieval accuracy was 83% when the images were preprocessed for uniformity in intensity and geometry. Principal component analysis can be applied to content...