Beginning with Release 11, Pixelink Capture includes a Focus Stacking feature. This feature can also be referred to as Z-stacking.
Focus Stacking produces a single image by combining multiple frames taken at different focus values. It uses the most 'in-focus' regions from each individual image to provide a greater depth of field. This feature can be useful if your image has targets at multiple planes. For example, an image where some objects are close to the camera and others are farther away.
Focus Stacking is supported for auto-focus cameras, as well as for cameras using the Navitar lens controller. The controls can be found on the Lens tab of Pixelink Capture, under "Multi Focus Points".
Please note that Focus Stacking is only supported in Pixelink Capture. It is not supported as a function of the SDK.
How to Use
Focus Stacking can be found at the bottom of the Lens tab of Pixelink Capture, under "Multi Focus Points". The controls are located near the bottom of the tab.
Focus stacking performs better when focusing on objects with clear edges and sharp contrast. Objects should be stationary. Movement during the capture process can negatively affect the quality of the final image.
First, select the Focus radio button, located above the video preview, to open the Focus ROI selection box.
Position the Focus ROI over the first focus point, and press Auto to perform a one time auto focus. In this example, the focus point was set to the text on the box closest to the camera.
Next, under Multi Focus Points, click Add to add the focus point to the list.
Move the focus ROI to the next location, and repeat for each focus point; Click Auto to auto focus, and Add to add the focus value.
As always, auto focus performs best when selecting focus point with clear and crisp edges.
You can remove focus values by selecting the value from the list, and clicking the Remove button.
When you're finished adding focus values, click the Focus Stack Images button to combine the frames from each of these focus values.
Note: It may take a minute or two for the process to complete.
A window will pop up that will allow you to select the location and name of the image you are saving. Images will be saved as .bmp files.
Switching Between Focus Points
If you want to cycle through the focus points which you have saved to the Multi Focus Points box, you can do so by clicking the "Start" button located under the Focus Points box. They will cycle through in the preview window. To stop cycling through the focus points, click the "Stop" button.
To adjust the duration and speed at which you cycle through the focus points, you can use the options above the Focus Points box. The "Update Focus Every" box will adjust the speed, and the "For Duration" box will adjust the total duration of time it will switch focus.
In the example below, it will switch between the two focus values every 2 seconds, and will stop after 1 minute passes.