Pixelink has partnered with Varioptic and Edmund Optics auto focus liquid lens technology to support OEM's who need help with auto focus applications. Pixelink Capture have developed a built in Auto focus application that supports both single point and multiple point auto focus. Not only this, Pixelink Capture will also demonstrate the speed of Auto Focus by displaying the Time (ms) taken for each autofocus.
Please note that the Lens tab will only be visible when an Auto Focus camera is connected. Otherwise, the tab will not be shown.
How to Manipulate The Controls
Note: To obtain the best results when using auto focus:
1) Make sure that you have an environment setup with moderate lighting conditions.
2) Make sure that the target contains well defined edges.
Exposure time (ms):
Click on the "Exposure Time" slider and drag to the desired exposure time setting, or enter the setting in the box provided. To have the camera determine the exposure time, click the Auto button and it will calculate a reasonable exposure time based on the average intensity of the image.
Note: Continuous Exposure can not be enabled when using Auto Focus. To disable Continuous exposure, uncheck the "Continuous" box
Click on "Gain" slider and drag to the desired gain setting, or enter the setting in the box provided, or Click on "Auto" to allow the camera to search for the best gain setting.
Note: The gain has the effect of increasing the noise along with the signal. Be careful when using this command. It is always preferable to increase the amount of light entering the camera. Use gain only for light starved applications.
Click on the "Focus" slider and drag it to the desired point where you will be able to achieve a satisfactory focus for the camera. Use the "Auto" button to let the camera decide the best Focus point on the target.
To select the auto focus ROI click on the "Focus" radio button at the top of the preview window. This will cause the Auto Focus ROI selection box to appear in the preview window. You can then drag the Auto Focus ROI selection box to the desired position.
The preview panel will report the time taken to complete the Auto Focus function.
Set Minimum and Maximum value to speed up Auto Focus
These buttons can be used to set a minimum and maximum value for the Auto Focus slider. By default, the Auto Focus slider has a minimum value of 1 and a maximum value of 46000. The Auto Focus algorithm usually searches this range to find the correct focus value of the object selected.
In order to increase the speed of Auto Focus, the user can also set a minimum and maximum value to shorten the range of the linear search. For instance, lets say the user knows that their focus value lies somewhere between 26000 to 32000. Instead of using the default scale from 1 to 46000, the user will be able to shorten their range by setting minimum value to 26000 and maximum value to 32000. This reduces the range for the linear search which in turn speeds up the algorithm for auto focus.
Setting it up:
1) Use the Focus slider or type in a focus value.
2) Click on "Set Minimum" to set this value as the new minimum.
3) Use the slider or key in another focus value in the Textbox.
4) Click on "Set Maximum" to set this value as the new maximum.
5) Click on Auto Focus button and you should see an improvement in your timing.
To reset the limits to the default values, click on "Reset Limits"
Speeding up Auto Focus time:
There are three factors that can improve the time to focus on an object.
1) Lower exposure time
Check the box beside any of the above three options to improve the speed of Auto Focus.
You can also view the time taken to perform an auto focus in the same tab.
Setting up Multiple Focus Points:
Pixelink Capture allows the user to set up two different focus points and snap between these two points for a duration set by the user. In order to enable multiple focus point, the user will need to check the checkbox beside "Enable Multi Focus Point". As soon as this checkbox is enabled, the user will have access to more options to set up multiple focus points.
In order to select Point 1 and Point 2, please make use of the following options.
1) Choose Auto Focus ROI button.
Clicking on this button will create an ROI on the preview window. Please see the example below.
The maximum size for this ROI is 512x512. You are able to set this ROI anywhere on the Preview window.
2) Auto Focus button to get the focus value of the selected preview.
Please follow the steps below to set up and perform multi point focus:
1) Check on "Enable Multi Focus Point" to enable its contents.
2) Click on "Choose Auto Focus ROI" button to select a particular region in your preview.
Note: Always try to select something with crisp edges. When using an image with poor image quality, the Auto Focus algorithm may not work properly. Please review the Quick Tips for Best Image Quality article for help obtaining a good quality image from your camera.
3) Once you have selected your object in the preview, use the Auto Focus button to automatically perform an Auto Focus on that point.
4) After one-time auto focus has completed, the textbox will display a focus value for that region. For instance, the textbox in the image above is displaying 32000.
5) Click on the "Set" button under Point 1 and it will automatically set that focus value.
6) Similarly, use the "Choose Auto Focus ROI" button to select another object or region in your Preview.
7) Perform an Auto Focus on that point.
8) After the one-time auto focus is complete, you will have a new focus value.
9) Click on "Set" button under Point 2 to set this Focus value.
Note: As the focus value gets set, it will be displayed under Point 1 and Point 2, as shown in the following screen shot:
10) After setting both focus points, set the timing for the loop.
11) Use "Set Focus Interval" to set the total time for Multi Focus, as seen in the screenshot below.
For instance, the Focus Interval set above will allow the camera to change its focus from Point 1 to Point 2 every 500 milliseconds. The entire process will continue for 1 minute.
Note: There is no limitation on the total duration.
12) After performing the steps above, click the "Start" button to begin Multi Point Auto Focus.
13) To stop Auto Focus at any time, press the "Stop" button.