After you’ve estimated your lens distortion, you can view the values on the LensDistortion tab. You can also change these to apply distortion to the input directly.
• Output Type - Select your output type depending on whether you want to distort the input image directly or just preserve the distortion information to use it on another image.
• Image - Choose to distort or undistort the input image.
• Displacement - Choose to leave the input image alone and store the pixel displacements corresponding to the calculated distortion in the UV channels so they can be used by the STMap node. Selecting the Displacement option enables you to analyze the distortion on one image or grid and use the STMap node to apply that distortion to another image. For more information, see Calculating the Distortion on One Image and Applying it to Another.
• Lens Type – Select your lens type. You can choose between Spherical and Anamorphic lenses.
• Radial Distortion 1 – Define the first radial distortion term. This is proportional to r2, where r is the distance from the distortion center. You can define this manually, or use image analysis, grid analysis, or line analysis to fill it out automatically.
• Radial Distortion 2 – Define the second radial distortion term, proportional to r4. You can define this manually, or use image analysis, grid analysis, or line analysis to fill it out automatically.
• Distortion Center – Define the values for the center of the radial distortion.
• Anamorphic Squeeze – Define the anamorphic squeeze value. If you select an anamorphic lens, the distortion in x is scaled by this amount.
• Asymmetric Distortion - This is enabled only for anamorphic lenses. Enter values to define asymmetric distortion to correct for slight misalignments between multiple elements in the lens.
• Analyze from Current Lens – Check to analyze the distortion from the current values. When this is selected, the Image Analysis and Grid Analysis modes skip their initial estimation steps and instead use the current parameter values as an initial guess from which to estimate the distortion. If you already have a rough idea of the distortion present, this can speed up the estimation, particularly for the Image Analysis mode.
• Undistort – Check to apply the inverse of the current distortion.
• Reset – Click to reset the parameters for zero distortion.
• filter - Select a filtering option. For more information on the filtering options, see Choosing a Filtering Algorithm.
• Distortion Scaling - Select either Scale to Input Format or Choose Format depending on whether you want to scale to your input format or select another format. By default the distortion is scaled according to the input format size. You might however want to select a different format, for example, if you have previously undistorted an image and changed the format to match the undistorted image size, then want to reapply the distortion later.
• Scale to Format - If you selected Choose Format next to the Distortion Scaling control, you can use this dropdown menu to select a format that you want to use to scale your image.
• Card Parameters – Fill in a, b and c values in the Card Parameters folder. These correspond to the parameters on the Lens Distortion tab of Nuke's Card node. For more information, see Applying Lens Distortion to a Card Node.
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