Igloo Core Engine
Igloo Core Engine
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Polynomial Wizard

The Polynomial Wizard allows you to calculate and apply polynomial texture distortion corrections to projectors. This is typically used to compensate for lens or screen curvature when a projector’s image does not project evenly across the display surface.

Start with a single projector and validate that the applied preset produces the correct output before applying it globally. If you plan to use the same preset across all projectors, ensure that their zoom, focus, and lens shift settings are identical.

Even small optical differences can affect image geometry, so some projectors may still require individually calibrated polynomial presets for optimal results.

Prerequisites

  1. Select Projector

    • In the Warping tab, select the projector you wish to apply polynomial warping to.

    • Disable all other projectors using the Enabled checkbox.

  2. Initial Warping

    • Reset the Warping for the selected projector

    • Warp the selected projector so that the top and bottom lines follow the physical curve of the screen.

    • At this stage, do not attempt to make the grid squares evenly sized.

    • Corner control points (Top Left, Top Right, Bottom Left, Bottom Right) should align with known marker points on the screen, based on drawings and projector throw calculations, not arbitrary visual alignment.

Using the Polynomial Wizard

  1. Grid Configuration

    • Enable Show Test Image to display the grid on the screen for measurement reference.

    • The test image dynamically updates based on the number of columns (horizontal) and rows (vertical) you set.

    • A default of 20 columns and 12 rows is recommended, but you can adjust these if you’re not getting accurate results.

  2. Distance Mode

    • Choose between:

      • Cumulative – Each value represents the total distance from the first line to the current line.

      • Non-Cumulative – Each value represents the distance between adjacent lines only.

  3. Measuring Distances

    • Measure to the center of each grid line.

    • Record horizontal distances (left to right) and vertical distances (top to bottom) in

    • Avoid pressing on the screen surface during measurement, as this may distort results.

    • You can use any units for measuring as long as you are consistent.

  4. Calculating Coefficients

    • Once all values are entered, press Calculate.

    • The resulting polynomial coefficients for X and Y will appear below.

Saving and Applying

  1. Save Preset

    • Enter a preset name and click Save to store the configuration for reuse.

    • Presets are saved to C:\ProgramData\Igloo Vision\IglooSetup\Polynomial Presets

  2. Applying Presets

    • In IglooSetup, open the Advanced tab of the Warping view and expand Polynomial Texture Scaling.

    • Select your saved preset from the Presets dropdown and click Apply to load it for the selected projector.

Tips

  • Preset files can be copied to other machines or shared between projects by placing them in the presets folder C:\ProgramData\Igloo Vision\IglooSetup\Polynomial Presets. Presets can also be imported manually via Config > Open Polynomial Preset.