Test Patterns

OVERVIEW
On this page you will find some test patterns Xeitoptics uses for projector and lens calibration.

They are supplied for download by customers and interested parties, but are not guaranteed to solve all or even any problems you may have! If you use them, you use them without any legal or moral responsibility from Xeitoptics for that use.

If you re-publish them please do so WITH appropriate attribution.

USING THE TEST PATTERNS
For the most part, these patterns are designed to be used WITHOUT vertical stretch.

They are all in 16:9 1920 x 1080 format. To download,

  • LEFT-click on the image to isolate it
  • Zoom to MAXIMUM size (using the “+” Magnifying Glass ikon until you see a “-” sign)
  • RIGHT-click on the image
  • Select “SAVE IMAGE AS…”
  • Transfer to a memory stick or similar device and plug into a suitable replay device (e.g. PlayStation, Blu-Ray player, PC, laptop etc.) for display.

NOTE: Some replay devices do not transfer the pattern pixel for pixel. This may be due to the replay device post-processing the image. Please make sure all such post-processing is turned OFF, if possible.

Also note that the size of some of these images can exceed 4 megabytes, particularly the detail-rich patterns.

Why use GREEN channel Test Patterns?
Most projection optics are designed based on the GREEN channel. Projection and anamorphic lenses work best at the GREEN wavelength (approximately 540nM). So Test Patterns that utilize the GREEN channel are the most useful for general focusing and will usually present the sharpest, clearest image, free of other colors and associated registration problems.

THE TEST PATTERNS

RESOLUTION

    Downloaders are reminded that some patterns have thumbnails in the outlines below. Do not mistake these thumbnails for the full patterns, which are placed always at the end of each outline.

    The patterns as depicted on this page are heavily compressed, reduced in size and, due to their rich detail, may appear blurred, or otherwise irregular on this page, in their compressed form.

    To download a full resolution image, you need to click on the pattern image, magnify it to the maximum extent (one mouse left-click) and only then perform the download.

1. 30 x 30 square grid plus Single Pixel Checkerboard (GREEN) – JPG file

(200% Thumbnail only: full pattern is below)

    This pattern contains a single-pixel checkerboard pattern superimposed over a 30-pixel square grid, using the GREEN channel only. The checkerboard pattern represents essentially the Nyquist frequency of your projection system (half the pixel pitch in each direction, vertical and horizontal).

    If the pixels are separated cleanly, then your system works at the Nyquist frequency, theoretically the maximum resolution it is capable of, as far as displaying visual information – i.e. movies, games and graphics – is concerned.

    Note that there is a difference between visual information designed to be displayed by a projector (movie content, graphics etc.) and channel artefacts, such as pixel tiling gaps, that you may also be able to observe when close to the screen.

    Channel artefacts contain no program material or relevant visual information. They are merely by-products of the display process. This is why projector manufacturers strive to make them as inconspicuous as possible. Nyquist frequency applies only to the former content: visual information. If you can see tiling gaps, that’s a plus!

    Note also that most filmed movie material rarely achieves Nyquist frequency, except (perhaps) in the film grain area. Animated features MAY include some material at, or approaching Nyquist frequency, but this is rare. Nyquist frequency IS, however, commonly achieved with the display of computer graphics and games.

2. 30 x 30 square grid plus Single Pixel Checkerboard (WHITE) – JPG file

    This pattern is essentially the same as Pattern #1, except it includes the BLUE and RED channels to make WHITE.

    Compared to the GREEN ONLY pattern, this pattern can be used for inspecting RGB registration.

3. Single Pixel Square Dot Array (GREEN) – JPG file

(200% Thumbnail only: full pattern is below)

    This is another variant on the “Nyquist” theme, except the pixels are in a square array, not checkerboarded.

4. Single Pixel “Wickerwork” Array (GREEN) – JPG file

    This is the inverse of Pattern #3. It is called “Wickerwork” because when viewed closely, the tiling gaps between pixels give the appearance of wickerwork.

5. Aperture Chart Test Pattern – JPG file

    This pattern shows where most of the common Aspect Ratios (apertures) used for movies, old and new, fit inside a 16:9 format image. It includes the 1.37:1, 1.33:1, 1.66:1, 1.78:1, 1.85:1, 2.21:1, 2.35:1, 2.37:1, 2.40:1, 2.55:1 and 2.76:1 ratios.

    Pixel values showing either the width or height of each aperture are shown in parentheses next to the Aspect Ratio listing on the screen.

    This pattern is to be used with and without vertical stretch, depending on application. On-screen user’s notes are included with the pattern.

6. Aspect Ratios: 2.40 versus 2.35 – Fitting the image to your screen – GIF file
This pattern is an Animated GIF, with a 5 second interval, designed to be played out of a PC or laptop. You can try using the pattern straight off this web site, or play it with a software package, such as Adobe Image Ready (in full screen mode).

    This full high-resolution animation shows the difference between a “2.35:1″ (818 pixels high) and a cropped “2.40:1″ version (800 pixels high) of the same image.

    Although the differences between the two aspect ratios are small, they can be important when setting up a projector for various screen aspect ratios, and for zooming to fit or masking a curved screen of either aspect ratio.

    Other “scope” aspect ratios have not been included as this pattern is designed for use with the two standard screen sizes “2.35:1″ and “2.40:1″.

7. General Purpose Focus Test Pattern (GREEN) – JPG file

(100% Thumbnail only: full pattern is below)

    This pattern features a combination of grids, single pixels, vertical and horizontal lines (1 and 2-pixel pitch), gray squares and 3×4 aspect ellipses.

    The 3×4 aspect ellipses, when expanded by an anamorphic lens, become circles.

8. General Purpose Focus Test Pattern (WHITE) – JPG file

    A WHITE version of Pattern #7.

9. Photo/Focus Test Pattern (RGB) – JPG file

    This pattern contains grids, 3×4 ellipses, randomly colored pixels and a model’s photograph in a repetitive array for testing geometry and flesh tones

10. ANSI Contrast Pattern – GIF file

This is a file designed to be replayed out of a PC or laptop. It is an animated GIF file, with an 8 second interval. It flips between two checkerboard patterns, dwelling for 8 seconds on each. Each pattern is the inverse of the other. Use it from within your browser (in full screen mode), or with appropriate GIF player software (e.g. Adobe ImageReady).

    “ANSI Contrast” is a measure of the contrast achievable within the total system. The basic procedure is to take measurements of black and of white rectangles at certain positions on the screen while simultaneously projecting a pattern that tests the optics and room dynamics of the system.

    A broad checkerboard pattern is usually used, and is provided here. The checkerboard pattern is used to make sure that there is a sufficient light emitted from the projector (and/or anamorphic) optics to simulate an evenly lit image, but containing large areas of 0% black and 100% white to allow measurement of the difference between them.

    A whole screen FULL ON to FULL OFF contrast measurement (see next pattern) does NOT provide this capability and should NOT be used to measure ANSI contrast. For a FULL-ON/FULL-OFF pattern, use the next pattern.

    ANSI Contrast measurements will also take room conditions into effect. As light spills off the screen and reflects around the theater environment it will eventually find its way back to the screen, invading adjacent black and white areas equally, thus lowering the ANSI contrast of the system.

    USING THE ANSI CONTRAST TEST PATTERN
    To use this GIF file, remove as many screen artefacts as possible to leave as much of the uncluttered raw pattern as possible. For example, if using ImageReady, zoom first to 100% and play the file. Then use the pattern full-screen by repeatedly pressing the “F” key until full screen mode is achieved, and by pressing the “TAB” key until all toolbars disappear.

    This file can be downloaded and edited to change the timing of the “flip”.

    NOTE: You should use an accurate, high dynamic range light meter. Ordinary photographic light meters may not be sensitive enough for this measurement.

  • Zoom the image to maximum size
  • Place your light meter over the area in which you wish to measure ANSI contrast
  • Note the “black” and the “white” readings as the pattern flips
  • Formula: “WHITE”/”BLACK” = ANSI Contrast.

11. FULL-ON/FULL-OFF Contrast Pattern – - GIF file
Note: this is another 8-second interval, GIF animation.

    “FULL-ON/FULL-OFF Contrast” is a way of measuring how much light your projector outputs, how deep its blacks are, and the relationship – contrast – between the two.

    FULL-ON/FULL-OFF contrast will always be much greater than ANSI contrast, because when it is in “black” mode there is no stray light to spill from the screen to the room and back again, or to diffuse and internally reflect through the projection optics onto the screen.

    Always remember, however, that ANSI contrast is the more appropriate measurement of the system’s contrast abilities in a more realistic “usage” environment.

    To use the FULL-ON/FULL-OFF contrast pattern, measure both the “black” and the “white” brightnesses as appropriate. Read the general guidelines on how to replay this pattern in the previous section.

    Formula: “WHITE”/”BLACK” = FULL-ON/FULL-OFF Contrast.

12. GREEN Field – JPG file

    This field consists of nothing but GREEN pixels. It can be used for inspecting the focus of inter-pixel tiling (usually about 6-8 times Nyquist Frequency).

13. WHITE Field – JPG file

    Allows the inspection of pixel tiling with RGB registration taken into account.

14. “Flying Spot” – to detect glare in projection optics – Quicktime .MOV file

This is a fully high-resolution (1920 x 1080) Quicktime .MOV “movie file” (about 320 kilobytes in size), but it is only just over a second long. It is recommended, indeed essential (given its function), this this file be played with a full frame player that has no borders around the image, such as VLC Player (Windows VLC Player download or Mac VLC Player download).

It is recommended that you DOWNLOAD this file first and then play it, rather than play it directly out of your browser when you intend to use it seriously, as browsers often introduce unwanted frames and other distractions to the final image.

Click on the link UNDERNEATH the image at the end of this section for the download link. The image is just a “summary”, a static representation of the contents of the movie.

    This pattern is designed to provide a black screen background (with only a very fine dark gray Xeitoptics logo – 8 units out of a possible 255 luminance – superimposed) with a 100% brightness white spot, so that maximum and minimum luminance can be measured at that particular point, virtually free of any flare effects or luminance crosstalk within the optical system that a full 1920 x 1080 white field – emitting light at all field positions simultaneously – might introduce or permit.

    Contrasted with a measurement taken from any position on the full 100% white field (a white reference field is available at the end of the “movie”), comparing the “flying spot” measurement in the same position should give an indication of the effect of flare and light spill on the white measurement.

    With all artificial mechanisms for altering brightness and contrast (such as “Dynamic Iris”) turned OFF:

    * Measure the flying spot brightness, then measure brightness using the full white field (pattern above) at the same spot:

    Formula: (FULL FIELD brightness)-(FLYING SPOT brightness) = EFFECT OF FLARE/SPILL etc.

    * You can also measure the flying spot brightness, say, at the extreme right, and compare it against the “black” level at the extreme left to see the effect of a small amount of light spill from the flying spot.

    * You can measure inside the spot and just outside it, in the black area) to measure local flare and spill.

    Technical details
    The file consists of a “Flying Spot”, a small 32-pixel 100% white square (0.05% of screen area) that dwells for three frames on the following positions: (Top, Middle and Bottom rows) x (Left, Center and Right columns) … 9 positions in all.

    If you play this file and blink at the same time, you won’t see it! In real time it is very short. The idea is to consider this file as a series of stills that are more easily accessed using a movie player than as still image viewer.

    Play the file through once and then use the movie player’s positional slider to sequence back through the file, frame by frame, until you find the square in the position you require. Wait a few seconds for the slider and mouse ikons to disappear, then take your measurements. If you wish, then compare this against the same position from the WHITE reference field at the end of the “movie”.

    Having only 9 spots effectively divides the player slider’s traverse into 9 sections, plus one for the WHITE reference screen at the end, 10 in all.

    NOTE! The above image is just an overview .JPG file.
    Use the following link to download and save the .MOV file:
    Xeitoptics “Flying Spot.MOV” download link
    (RIGHT-CLICK on link, “SAVE AS…”)