# Custom Multi Camera ToolBlock Finder

Custom Mulit Camera Toolblock finder can be used when the result feature should be computed based on images from multiple cameras. This topic introduces how to use Custom Multi Camera Toolblock finer using an example of computing a point feature based on three images.

In this example, three cameras are looking at one part: two are focusing at corners on one side, and one focusing on a circle on the other side.

Based on customer's requirement, the feature result is a single point feature whose x and y are same with the circle center's, rotation is the angle of fitted line of the two corner points.

Since the final feature is a point feature, the feature type of finder component should be set as "Point" in the Configuration Wizard.

In the generated program, after calibration and acquiring three run time images of the part in run mode, users can start configuring Custom Multi Camera ToolBlock Finder:

1. In the "Finders" panel, one can find "Multi Camera Finders" category where custom multi camera toolblock should be added.

   - New: Select "Multi Camera Finders" and then click "New" button, in the opened drop-down list, choose "Custom MulitCam Toolblock"

   - Run: Select the added tool block, and then click "Run" button to run it once to get the input images

   - Edit: Click "Edit" button and select "Edit multi-cam custom toolblock settings" to enter edit mode

2. In the setting page of the Multi Camera Custom Toolblock, add an inner ToolBlock, create its inputs and outputs, and link them as shown below.

3. Within the inner toolblock, add three sub toolblocks to find two corner points and one circle center respectively. For more information about how to find corners or circle in toolblock, please refer to Custom Toolblock Point Finder.

4. In added inner toolblock's scripts (C# simple script), input the following code to compute the result feature's x, y, and theta.

Note: Similar with custom toolblock point finder, the units of RotationX and RotationY here are radian, AlignPlus program will later transfer them into degrees and save them in a CogAlpsPointFeature object.

Here is the result of feature finding and align result using the result from the Custom Multi Camera Toolblock.