#Copy spears and munsil test patterns generator
#Copy spears and munsil test patterns software

#Copy spears and munsil test patterns generator

The original PLUGE generator used only -4% and +4% bars on a black background, but that left a fairly wide range of settings that would look correct.

The idea of the pattern is to set the brightness control until the two left bars are not visible and the two right bars are visible. In a system where 100% represents reference white, and 0% represents reference black, the four bars are set to -4%, -2%, 2%, and 4%, counting left to right.

There is are two bars set to levels below reference black and two set to levels above reference black. There are four vertical bars on a background that is reference black (code value 16 in 8-bit video). This is a very simple pattern used to set the brightness control. Every pattern on the disc has something about it that makes it unique, even the basic patterns like PLUGE and Color Bars. We used the same philosophy for simple patterns as well as complex ones. All of our patterns are built to use the absolute highest bandwidth available to modern all-digital equipment. Since our patterns were built using an all-digital signal path and will never be broadcast, we donвЂ™t need to conform to FCC bandwidth limitations or roll off high frequencies to avoid causing problems for old CRT displays. For a long time, all the standard video patterns have been designed for the limitations of analog broadcast.

Build patterns with digital in mind from the beginning.

Where we needed to anti-alias lines and curves (for example in the sharpness pattern) we oversampled each pixel (again, with custom-written software) by 256x or more to get the smoothest possible edges and contours. In most cases, the patterns were generated using 64-bit floating point values for each channel of each pixel, and then converted to 8-bit using special dithering algorithms to preserve dynamic range.

Use the very best algorithms and the highest precision.

Similarly, most of the patterns were generated directly in 4:2:0, which again canвЂ™t be created natively by image editors.

#Copy spears and munsil test patterns software

This necessitated building our own pattern generation code, as no existing image editing software works in YCbCr natively. For example, if the pattern is for evaluating YCbCr issues, we built the pattern in YCbCr space directly rather than creating it in RGB and converting.

Build each pattern in the color space and format that made the most sense.

Overview We had several goals building these patterns: