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
Gain (dB):
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.
Focus (dB):
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 ROI" 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 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
2) Binning
3) Decimation
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 multiple different focus points and snap between these points for a duration set by the user. Using the focus slider or auto focus tool, adjust the camera's focus to the desired value. Click add to add this position to the list of multi-focus points. Once the desired number of focus points has been added click START to cycle through them for the duration in interval specified. Click STOP to halt this process.
You can also click "Focus Stack Images" to combine images at the various focus points into one image using the most in focus sections of each image. This is a very computational resource intensive task so to speed up this operation limit the ROI size and number of images to combine.
The following steps will allow you to set up 2 focus points:
1) Choose a Focus ROI
The maximum size for the focus ROI can vary from camera to camera.
Adjust the adorner to adjust the size of the Focus ROI. You are able to set this ROI anywhere on the Preview window.
2) Press Auto to perform an auto focus operation, which will return the focus value of the selected focus ROI.
To set up and perform multi point focus:
1) Under Multi Focus Points, click “Add” to add this first focus value as a focus point.
2) Click on "Choose Auto Focus ROI" button to select a new 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 3912.
5) Click “Add” to add this new focus value to the list.
6.) Repeat these steps for each focus point: Reposition the focus ROI, press auto to one time auto focus, and Add the new value to the Multi Focus Points list.
Note: As focus values are Added, they will be listed by their focus value, as shown in the following screen shot:
10) After setting the desired number of focus points, set the timing for the loop.
For instance, the Focus Interval set above will allow the camera to change its focus between the listed values every 500 milliseconds. The entire process will continue for 1 minute.
Note: There is no limitation on the total duration.
12) Click the "Start" button to begin Multi Point Auto Focus.
13) To stop Auto Focus at any time, press the "Stop" button.
Focus Stacking
Click "Focus Stack Images" to combine the images from each focus value into a single image, using the most "in focus" region from each image. This operation will use images taken from each focus value added to the Multi Point Focus list.