Black Level#

The Black Level camera feature allows you to change the overall brightness of an image. Adjusting the camera's black level will result in an offset to the pixel's gray values output by the camera.

For example, you can increase the gray value of each pixel in the image by 3.

Using the Feature#

Adjusting the Black Level#

To adjust the black level, enter a value for the BlackLevel parameter.

The change in the gray value resulting from the BlackLevel parameter value depends on the camera model.

Types of Black Level Adjustment#

On racer 2 L camera models, the BlackLevelSelector parameter is available. This parameter allows you to choose between two types of black level adjustment. You can also perform both types of adjustment at the same time.

To configure black level adjustment:

1. Set the BlackLevelSelector parameter to one of the following values:
   • All: The black level value is applied universally.
   • SensorAll: The black level value is applied to the sensor.
     You can both increase and decrease the black level, which can be useful, e.g., if you want to set bright pixel values in the dark field to zero.
2. Specify the desired black level.
3. Optional: If you want to perform both types of black level adjustment, set the BlackLevelSelector parameter to the other value and repeat step 2.

Specifying a black level value of 0 effectively disables the respective adjustment.

Black Level Compensation#

Dark current can have a negative impact on image quality. Some image sensors can compensate for this by automatically adjusting the black level.

On some camera models, you can manually enable or disable this automatic adjustment using the BslBlackLevelCompensationMode parameter.

To do so, set the BslBlackLevelCompensationMode parameter to one of the following values:

• Sensor: Black level compensation is performed by the image sensor. The sensor tries to compensate for thermally generated voltages that would affect the signals (dark current).
• Off: Black level compensation is disabled. This is useful, e.g., for quantitative analysis of weak light signals or if you need raw image data without dark current correction.
  Setting the compensation mode to Off resets all internal correction values used for black level compensation.

Specifics#

Show all camera models

Sample Code#

ace Classic/U/L GigE Cameras#

// Set the black level to 32
camera.BlackLevelRaw.SetValue(32.0);
// Disable black level compensation
// Note: Available on selected camera models only
camera.BslBlackLevelCompensationMode.SetValue(BslBlackLevelCompensationMode_Off);

INodeMap& nodemap = camera.GetNodeMap();
// Set the black level to 32
CFloatParameter(nodemap, "BlackLevelRaw").SetValue(32.0);
// Disable black level compensation
// Note: Available on selected camera models only
CEnumParameter(nodemap, "BslBlackLevelCompensationMode").SetValue("Off");

// Set the black level to 32
camera.Parameters[PLCamera.BlackLevelRaw].SetValue(32.0);
// Disable black level compensation
// Note: Available on selected camera models only
camera.Parameters[PLCamera.BslBlackLevelCompensationMode].SetValue(PLCamera.BslBlackLevelCompensationMode.Off);

/* Macro to check for errors */
#define CHECK(errc) if (GENAPI_E_OK != errc) printErrorAndExit(errc)
GENAPIC_RESULT errRes = GENAPI_E_OK;  /* Return value of pylon methods */
/* Set the black level to 32 */
errRes = PylonDeviceSetFloatFeature(hdev, "BlackLevelRaw", 32.0);
CHECK(errRes);
/* Disable black level compensation */
/* Note: Available on selected camera models only */
errRes = PylonDeviceFeatureFromString(hdev, "BslBlackLevelCompensationMode", "Off");
CHECK(errRes);

# Set the black level to 32
camera.BlackLevelRaw.Value = 32.0
# Disable black level compensation
# Note: Available on selected camera models only
camera.BslBlackLevelCompensationMode.Value = "Off"

Other Cameras#

// Enable sensor black level adjustment
// Note: Available on racer 2 L camera models only
camera.BlackLevelSelector.SetValue(BlackLevelSelector_Sensor);
// Set the black level to 32
camera.BlackLevel.SetValue(32.0);
// Disable black level compensation
// Note: Available on selected camera models only
camera.BslBlackLevelCompensationMode.SetValue(BslBlackLevelCompensationMode_Off);

INodeMap& nodemap = camera.GetNodeMap();
// Enable sensor black level adjustment
// Note: Available on racer 2 L camera models only
CEnumParameter(nodemap, "BlackLevelSelector").SetValue("Sensor");
// Set the black level to 32
CFloatParameter(nodemap, "BlackLevel").SetValue(32.0);
// Disable black level compensation
// Note: Available on selected camera models only
CEnumParameter(nodemap, "BslBlackLevelCompensationMode").SetValue("Off");

// Enable sensor black level adjustment
// Note: Available on racer 2 L camera models only
camera.Parameters[PLCamera.BlackLevelSelector].SetValue(PLCamera.BlackLevelSelector.Sensor);
// Set the black level to 32
camera.Parameters[PLCamera.BlackLevel].SetValue(32.0);
// Disable black level compensation
// Note: Available on selected camera models only
camera.Parameters[PLCamera.BslBlackLevelCompensationMode].SetValue(PLCamera.BslBlackLevelCompensationMode.Off);

/* Macro to check for errors */
#define CHECK(errc) if (GENAPI_E_OK != errc) printErrorAndExit(errc)
GENAPIC_RESULT errRes = GENAPI_E_OK;  /* Return value of pylon methods */
/* Enable sensor black level adjustment */
/* Note: Available on racer 2 L camera models only */
errRes = PylonDeviceFeatureFromString(hdev, "BlackLevelSelector", "Sensor");
CHECK(errRes);
/* Set the black level to 32 */
errRes = PylonDeviceSetFloatFeature(hdev, "BlackLevel", 32.0);
CHECK(errRes);
/* Disable black level compensation */
/* Note: Available on selected camera models only */
errRes = PylonDeviceFeatureFromString(hdev, "BslBlackLevelCompensationMode", "Off");
CHECK(errRes);

# Enable sensor black level adjustment
# Note: Available on racer 2 L camera models only
camera.BlackLevelSelector.Value = "Sensor"
# Set the black level to 32
camera.BlackLevel.Value = 32.0
# Disable black level compensation
# Note: Available on selected camera models only
camera.BslBlackLevelCompensationMode.Value = "Off"

You can also use the pylon Viewer to easily set the parameters.