Ocula is a set of tools for dealing with everyday problems encountered in stereo post-production. It consists of:
The O_VerticalAligner plug-in lets you warp views vertically so that their corresponding features align, while keeping the horizontal position of each pixel the same.
If the cameras used to shoot stereoscopic images converge (point inwards), some features in the resulting two views may be vertically misaligned. This is called keystoning. It is a common problem when shooting images with converging cameras. Parallel cameras do not produce the same problem.
O_ColourMatcher lets you match the colours of one view with those of another. It has been specifically designed to deal with the subtle colour differences that are sometimes present between stereo views.
O_InteraxialShifter lets you change the interocular separation of stereo images; that is, the distance between the two cameras. Using this plug-in, you can generate two new views at specified positions between the original images.
O_Correlate is a collection of tools to assist you when rotoscoping, creating paint effects, or doing other operations dependent on image locality. It provides extensions directly to NUKE's existing Correlate function.
O_Solver is fundamental to the operation of the toolset. It controls the key-frameable calibration of camera pairs from stereo footage, to allow artist control of how the toolset reacts to changing camera geometry through a shot.
O_DisparityGenerator is used to create disparity fields for stereo images. A disparity field maps the location of a pixel in one view to the location of its corresponding pixel in the other view. It includes two sets of disparity vectors: one maps the left view to the right, and the other maps the right view to the left.
O_DisparityViewer draws arrow overlays to allow easy visualisation of your vector field.
Using the O_NewView plug-in, you can create a single view from a stereo pair of images. You can create this new view at any position between the original views. The new view replaces both of the existing views.
Many Ocula plug-ins rely on disparity fields to produce their output. Usually, disparity fields are created using a combination of the O_Solver and O_DisparityGenerator nodes. However, if you have a CG scene with camera information and a z-depth map available, you can also use this O_DepthToDisparity plug-in to generate the disparity field. Provided that the camera information and z-depth map are correct, this is both faster and more accurate than using the O_Solver and O_DisparityGenerator nodes.
O_DisparityToDepth generates z-buffer depth maps per view in a stereo pair. The z-buffer depth data can then be used elsewhere in the NUKE pipeline – for example to perform depth of field effects.