Random Pattern (Noise) Test Chart

March 3, 2014
June 29, 2022

$330.00$570.00

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).

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Description

 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″
(305mm × 305mm)
22.4″ × 16.8″
(569mm × 426mm)
24″ × 18″
(610mm × 458mm)
Medium 8″ × 8″
(203mm × 203mm)
14.93″ × 11.2″
(379mm × 284mm)
16″ × 12″
(458mm × 305mm)
Small 6″ × 6″
(152mm × 152mm)
11.2″ × 8.4″
(284mm × 213mm)
12″ × 10″
(305mm × 254mm)
X-Small
(High Precision Transmissive)
5.536″ × 5.536″
(141mm × 141mm)
9.25″ × 7.75″
(159mm × 197mm)
10″ × 8″
(254mm x 203mm)

Read more about Random/Dead Leaves chart analysis  in the Imatest documentaion.