My image is too dark using a Basler camera
Solution # 1: Open the aperture on the lens more
1. Twist the aperture on the lens to “Open” until the image has the desired brightness in your Noldus software.
Solution # 2: Increase the gain and/or exposure in Pylon
1. Close your Noldus software (e.g., MediaRecorder or EthoVision XT) on the PC.
2. Start the Basler Pylon Viewer software that comes with the camera. It can normally be found as an icon on the desktop. Otherwise, look in the Start menu under Basler.
- NOTE The Basler Pylon Viewer software is installed automatically when you install the camera drivers.
3. Choose Tools > Options and check that the User level is set to Expert or Guru.
4. In the Devices panel, double-click the item Basler under GigE or USB depending on the camera you have.
5. In the Features panel, open the Basler camera item and then double-click Analog Controls.
- NOTE If you do not see the Features panel, go to Window and make sure the Features option is checked
6. Increasing the gain: Under Analog Control, increase the Gain (Raw) up to 2.
NOTE A higher gain setting will result in a brighter image, while a lower gain setting will result in a darker image. Very high settings may increase the noise or graininess of the image.
7. You can check the resulting changes by clicking the Continuous Shot button on the toolbar.
8. Increasing the exposure: Make sure Exposure Auto to set to Off.
9. Set Exposure Time (Abs) [us], enter the exposure time you require, in microseconds. Press Tab or click another field to confirm.
NOTE A higher exposure setting will result in a brighter image, while a lower exposure setting will result in a darker image. However, too-high exposure will result in dropped frames, and too-low exposure may result in an image that flickers or changes rapidly between light and dark.
For non-DanioVision set-ups, this value will typically vary between 8,000 and 25,000 depending on your lighting needs and your Gain setting in Pylon (more on Gain below).
IR lighting is the exception to the above. When tracking in IR with an NIR GigE camera, you may need an exposure setting around 30,000 in order to brighten up the image enough for tracking in EthoVision.
For DanioVision setup, values should be 4000 (with a camera resolution of 1280x960) or 2000 (with a camera resolution of 640x480).
10. To check that any alterations in the gain or exposure is compatible with your frame rate, click the Continuous Shot button on the toolbar.
11. At the bottom of the live video window, locate the frame rate resulting with the new exposure time. This should be the same as the one next to Acquisition Frame Rate (Abs) [Hz]. (Noldus recommends 25 or 30)
12. If the resulting frame rate is lower than Acquisition Frame Rate (Abs) [Hz], then stop the Continuous Shot and either:
a. lower the exposure time and adjust the Gain (Raw) instead (see #6 above),
b. open the lens diaphragm to compensate for this (if not done already, see the beginning of this article), or
c. lower the video resolution. This is under AOI Controls and can be reduced by lowering the Width and Height. This will help if the exposure is close to the limit, but not if the exposure is extremely high.
- NOTE Lowering the resolution will make the image look more “zoomed in”. Also, make sure the Center X and Center Y are checked.
Repeat steps until you see the expected framerate.
13. Once finished with any gain or exposure alterations, stop the Continuous Shot and open the Configuration Sets item and:
a. select User Set 1 from the Configuration Set Selector,
b. click Execute next to User Set Save (the camera settings set in the previous steps are now saved under User Set 1),
c. select User Set 1 from the Default Startup Set list,
d. close Pylon Viewer.
- NOTE These settings will be used each time you start up your Noldus software.
TIP You can also save different settings for the same camera in User Set 2 and User Set 3. Under Default Startup Set (User Set Default), select which you want your Noldus software to use.