Random Pattern (Noise) Test Chart
본문
The Imatest Random Pattern chart is a variant of the Dead Leaves chart designed to measure texture sharpness.The Random pattern is the extreme pattern for noise reduction: it maximizes noise reduction while minimizing sharpening, improving the accuracy and robustness of measurements. In addition, gray regions to the left and right of the chart facilitate noise removal (using a technique where gray patch noise Power Spectral Density is subtracted from the signal + noise PSD of the central Spilled coins region).
Detail information
The Imatest Random Pattern chart for measuring texture sharpness has several key features:
- It contains slanted edges (2:1 and 4:1 contrast) for convenient comparisons with the dead leaves pattern.
- The gray area to the left and right of the random pattern has the same mean density as the random pattern, allowing it to be used for effective noise PSD removal using the McElvain et. al. technique.
- Registration marks and 16 grayscale patches are included. The linear levels used to create the grayscale patches are 0 through 255 in steps of 17 (same as the Siemens Star chart in the draft of the upcoming ISO 12233 standard).
| Chart Dimensions | Random Pattern Region | Printed region | Media size total |
|---|---|---|---|
| Large | 12" × 12" 305 mm × 305 mm | 22.4" × 16.8" 569 mm × 426 mm | 24" × 18" 610 mm × 458 mm |
| Medium | 8" × 8" 203 mm × 203 mm | 14.93" × 11.2" 379 mm × 284 mm | 16" × 12" 458 mm × 305 mm |
| Small | 6" × 6" 152 mm × 152 mm | 11.2" × 8.4" 284 mm × 213 mm | 12" × 10" 305 mm × 254 mm |
| X-Small (High Precision Transmissive) | 5.536" × 5.536" 141 mm × 141 mm | 9.25" × 7.75" 159 mm × 197 mm | 10" × 8" 254 mm × 203 mm |
Read more about Random/Dead Leaves chart analysis in the Imatest documentaion.
- 이전글Log Frequency Contrast Chart 23.04.20
- 다음글Black & White Imatest Spilled Coins (Dead Leaves) Test Chart 23.04.20