O_DisparityToDepth Example

In this example, we first generate a depth map for a stereo pair of images using O_DisparityToDepth. Then, we blur the image according to the depth map.

Step by Step

Launch Nuke and select File > Open to import the depth.nk script. This script has the left and the right view set up in the Project Settings. In the Node Graph, there is a stereo Camera node.

Select Image > Read to import Dance_Group.exr into Nuke.

To calculate disparity vectors, insert an O_DisparityGenerator node after the image. See DisparityGenerator for more information.

Select Ocula > Ocula 4.0 > O_DisparityToDepth to insert an O_DisparityToDepth node after the O_DisparityGenerator node. Ensure the O_DisparityGenerator node is connected to the Disparity input of O_DisparityToDepth.

Connect the Camera node to the Camera input of O_DisparityToDepth. Your node tree should now look something like this:

Select depth from the channel dropdown above the Viewer to display the z-depth map.

Select the red channel (R) from the RGB dropdown, and adjust the gain and gamma sliders above the Viewer to see the depth map more clearly.


The left view of a stereo image.	The red channel of the depth map (with adjusted gain and gamma).

To use O_DisparityToDepth with ZDefocus, continue to the next section.

An Example of Using O_DisparityToDepth with ZDefocus

The ZDefocus node blurs the image background according to the depth channels we’ve just created in the previous section.

Continue with the node tree you created in the previous section.

If you inserted a DisparityReviewGizmo node, either disable or delete it.

Select Filter > ZDefocus to add a ZDefocus node between O_DisparityToDepth and the Viewer. Your node tree should now look something like this:

Open the ZDefocus controls. A focal_point widget is displayed in the Viewer. Click and drag the focal_point widget to the area on the image you want to be in focus. In this case, we want the dancer at the front to be the focus point.

Then set the ZDefocus controls as follows:

• channels to rgba

• math to far=0

• size to 63

View the output. To see the effect of the ZDefocus node more accurately, select the node in the node tree and press D once to disable and again to enable it.


The left view when the ZDefocus node is disabled.	The left view when the ZDefocus node is enabled.

You can save the depth in the channels of the input clip for later use. To do this, select Image > Write to insert a Write node between O_DisparityToDepth and ZDefocus. In the Write node controls, select all from the channels dropdown menu. Use the file control to give the file a location and a new name. Choose exr as the file type and click Render to render the image.