DGA-6000 ULTRA-HD VIDEO GENERATOR / ANALYZER USER MANUAL
B-10
Motion Pattern Notes
Zone Plates -
Zone Plates are one of the most useful tools available to engineers that design video
processing algorithms for displays and stand-alone video processors. Zone plate images can include all
possible spatial frequencies up to the Nyquist limits, which are determined by the pixel width and line count
height of video frame formats. Hence, static and moving zone plates provide the ability to analyze the
performance of linear and non-linear video processing technologies and algorithms.
Circular Zone Plate –
The Circular Zone Plate (ZP) has historically been the most common zone plate
available to consumers. The Circular ZP is characterized by horizontal and vertical spatial frequencies that
are linearly proportional to the distance from the center (radius) of the zone plate. Hence the resulting zone
plate image is circular. Circular zone plates are often bounded at or below the Nyquist sampling frequency,
or they may be produced as full-field images.
Full-field zone plates are particularly useful to quickly examine horizontal and vertical filtering applied during
deinterlacing or scaling to avoid aliasing. Circular zone plates in motion instantly reveal non-linear artifacts
associated with deinterlacing, detail enhancement, and smooth-motion interpolation technology.
Observations can be quantitative using the real-time active cursors to measure the onset of spatial
frequency effects and artifacts, or qualitative by noting the type and severity of non-linear artifacts, or a
combination of both. It is especially important to note that artifacts vary with motion rate, direction of
movement, and proximity to stationary images and field borders.
Hyperbolic Zone Plate –
The Hyperbolic Zone Plate (ZP) is less common than the Circular Zone Plate
among consumers, but it is often more useful for analytical purposes. The Hyperbolic ZP is characterized by
having constant horizontal frequency along each horizontal line of the image and a constant vertical
frequency up and down each column (vertical line) of pixels. The horizontal frequency increases linearly with
the vertical distance from the zone plate origin, while the vertical frequency increases linearly with the
horizontal distance from the origin.
Resolution (Wedge) –
Resolution Wedge patterns can be used to measure effective resolution, which
includes the ability to discern horizontal and vertical resolution with motion. Vertical Resolution Wedges
“point” horizontally, while conversely, Horizontal Resolution Wedges “point” vertically. The DGA-6000
wedges are generated in three sizes, each composed of a fixed number of cosine cycles (2, 6, or 14), where
the spatial frequency of the cosine increases linearly toward the narrow end of the wedge. The cosine
frequency at the wide end of a wedge is slightly less than 20% of the Nyquist frequency, and 90% of the
Nyquist frequency at the narrow end of the wedge. Resolution wedges are provided in four directional
orientations (pointing left, right, top, bottom) to make it possible to check resolution near the edges of the
display if desired. There are also patterns that combine wedges in all four directions to simultaneously
observe the effects of motion on horizontal and vertical resolution.
An Example of Measuring Effective Resolution with and without Motion –
1) Set the DGA-6000 Format to match the native resolution of the display. For instance, if the native
display resolution is 1920x1080 pixels select 1080i to make interlaced video resolution
measurements (with deinterlacing), or 1080p to make progressive video resolution measurements.
2) Select % Nyquist cursor units from the Units menu item to measure the effective resolution as a
Kell Factor, or select L/PW or TVL to measure directly in resolution units.
3) To measure the effective static (non-moving) vertical resolution, select one of the vertical resolution
wedges (which point horizontally) in the Motion Pattern menu. (Conversely, select one of the
horizontal resolution wedges to measure horizontal resolution.) Set the vertical movement
increment to V00.
4) Enable the cursor and move it toward the narrow end of the static wedge until the cursor is at the
location where the cosine cycles (bright and dark lines) in the wedge can no longer be clearly
discerned as individual lines. That is the effective static vertical resolution of the image. The static
resolution will typically be 60% to 80% of the Nyquist frequency. This is also called the Kell factor.
Selecting the precise limit of discernibility is somewhat subjective, and varies by display and
