Exposure Auto#

相机的 Exposure Auto 功能会自动在指定限值内调整曝光时间，直到达到目标亮度为止。

自动功能的像素数据可以来自一个或多个自动功能 ROI。

如果要同时使用 Exposure Auto 和 Gain Auto，使用 Auto Function Profile 功能可以指定如何平衡两者效果。

要手动调整曝光时间，请使用 Exposure Time 功能。

该功能的使用#

启用或禁用 Exposure Auto#

要启用或禁用 Exposure Auto 自动功能：

将至少一个自动功能 ROI 分配给 Exposure Auto 自动功能。
确保自动功能 ROI 部分或完全与图像 ROI 重叠。
将 ExposureMode 参数设置为 Timed。
设置 ExposureAuto 参数设置为以下工作模式之一：
- Once：相机调整曝光时间，直至达到指定的目标亮度值。完成此操作后，或最多经过 30 个计算周期后，相机会将自动功能设置为 Off。相机会将以下计算得出的曝光时间应用于所有后续图像。
- Continuous：相机在采集图像时连续调整曝光时间。
- Off：禁用 Exposure Auto 功能。曝光时间保持为上次自动或手动调整后的值。

信息

当相机连续拍摄图像时，自动功能会在经过较短的延迟后生效。前几张图像可能不受自动功能的影响。

指定下限和上限#

自动功能会在您指定的限值范围内调整 ExposureTime 参数值。

要更改限值，请将 AutoExposureTimeLowerLimit 和 AutoExposureTimeUpperLimit 参数设置为所需值（单位为 µs）。

示例：假设您已将 AutoExposureTimeLowerLimit 参数设置为 1000，并将 AutoExposureTimeUpperLimit 参数设置为 5000。在自动调节过程中，曝光时间将永远不会低于 1000 µs 且不会高于 5000 µs。

如果将 AutoExposureTimeUpperLimit 参数设置为较高的值，则相机的帧速率可能会降低。

指定目标亮度值#

自动功能会调整曝光时间，直至达到目标亮度值（即平均灰度值）为止。

要指定目标值，请使用 AutoTargetBrightness 参数。

信息

目标值计算不包括其他图像优化，例如 Gamma。根据设置的图像优化，相机输出的图像平均灰度值可能会明显低于或高于目标值。
相机还使用 AutoTargetBrightness 参数来控制自动功能 Gain Auto。如果要同时使用 Exposure Auto 和 Gain Auto，使用 Auto Function Profile 功能可以指定如何平衡两者效果。
For racer 2 S line scan cameras with CXP interface, the following is true:
The algorithm for generating the target brightness value is applied on the "camera side", and therefore only applied to a single line, not to the complete frame. The complete frame is built in the frame grabber where the randomly selected lines with the applied target brightness value are part of the assembled frame.
在部分相机机型上，您可以使用 Remove Parameter Limits 功能提高目标值参数的上限。

在 Basler ace GigE 相机型号上，您还可以指定一个 Gray Value Adjustment Damping 系数。在 Basler dart 和 pulse 相机型号上，您可以指定 Brightness Adjustment Damping 系数。

如果使用阻尼系数，则达到目标值的速度会更慢。

示例代码#

ace Classic/U/L GigE 相机#

C++ (Native)C++ (Generic)C#C (Generic)Python

// Set the Exposure Auto auto function to its minimum lower limit
// and its maximum upper limit
double minLowerLimit = camera.AutoExposureTimeLowerLimitRaw.GetMin();
double maxUpperLimit = camera.AutoExposureTimeUpperLimitRaw.GetMax();
camera.AutoExposureTimeLowerLimitRaw.SetValue(minLowerLimit);
camera.AutoExposureTimeUpperLimitRaw.SetValue(maxUpperLimit);
// Set the target brightness value to 128
camera.AutoTargetValue.SetValue(128);
// Select auto function ROI 1
camera.AutoFunctionAOISelector.SetValue(AutoFunctionAOISelector_AOI1);
// Enable the 'Intensity' auto function (Gain Auto + Exposure Auto)
// for the auto function ROI selected
camera.AutoFunctionAOIUsageIntensity.SetValue(true);
// Enable Exposure Auto by setting the operating mode to Continuous
camera.ExposureAuto.SetValue(ExposureAuto_Continuous);

INodeMap& nodemap = camera.GetNodeMap();
// Set the Exposure Auto auto function to its minimum lower limit
// and its maximum upper limit
double minLowerLimit = CFloatParameter(nodemap, "AutoExposureTimeLowerLimitRaw").GetMin();
double maxUpperLimit = CFloatParameter(nodemap, "AutoExposureTimeUpperLimitRaw").GetMax();
CFloatParameter(nodemap, "AutoExposureTimeLowerLimitRaw").SetValue(minLowerLimit);
CFloatParameter(nodemap, "AutoExposureTimeUpperLimitRaw").SetValue(maxUpperLimit);
// Set the target brightness value to 128
CIntegerParameter(nodemap, "AutoTargetValue").SetValue(128);
// Select auto function ROI 1
CEnumParameter(nodemap, "AutoFunctionAOISelector").SetValue("AOI1");
// Enable the 'Intensity' auto function (Gain Auto + Exposure Auto)
// for the auto function ROI selected
CBooleanParameter(nodemap, "AutoFunctionAOIUsageIntensity").SetValue(true);
// Enable Exposure Auto by setting the operating mode to Continuous
CEnumParameter(nodemap, "ExposureAuto").SetValue("Continuous");

// Set the Exposure Auto auto function to its minimum lower limit
// and its maximum upper limit
double minLowerLimit = camera.Parameters[PLCamera.AutoExposureTimeLowerLimitRaw].GetMinimum();
double maxUpperLimit = camera.Parameters[PLCamera.AutoExposureTimeUpperLimitRaw].GetMaximum();
camera.Parameters[PLCamera.AutoExposureTimeLowerLimitRaw].SetValue(minLowerLimit);
camera.Parameters[PLCamera.AutoExposureTimeUpperLimitRaw].SetValue(maxUpperLimit);
// Set the target brightness value to 128
camera.Parameters[PLCamera.AutoTargetValue].SetValue(128);
// Select auto function ROI 1
camera.Parameters[PLCamera.AutoFunctionAOISelector].SetValue(PLCamera.AutoFunctionAOISelector.AOI1);
// Enable the 'Intensity' auto function (Gain Auto + Exposure Auto)
// for the auto function ROI selected
camera.Parameters[PLCamera.AutoFunctionAOIUsageIntensity].SetValue(true);
// Enable Exposure Auto by setting the operating mode to Continuous
camera.Parameters[PLCamera.ExposureAuto].SetValue(PLCamera.ExposureAuto.Continuous);

/* 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 */
double minLowerLimit = 0;
double maxUpperLimit = 0;
/* Set the Exposure Auto auto function to its minimum lower limit */
/* and its maximum upper limit */
errRes = PylonDeviceGetFloatFeatureMin(hdev, "AutoExposureTimeLowerLimitRaw", &minLowerLimit);
CHECK(errRes);
errRes = PylonDeviceGetFloatFeatureMax(hdev, "AutoExposureTimeUpperLimitRaw", &maxUpperLimit);
CHECK(errRes);
errRes = PylonDeviceSetFloatFeature(hdev, "AutoExposureTimeLowerLimitRaw", minLowerLimit);
CHECK(errRes);
errRes = PylonDeviceSetFloatFeature(hdev, "AutoExposureTimeUpperLimitRaw", maxUpperLimit);
CHECK(errRes);
/* Set the target brightness value to 128 */
errRes = PylonDeviceSetIntegerFeature(hdev, "AutoTargetValue", 128);
CHECK(errRes);
/* Select auto function ROI 1 */
errRes = PylonDeviceFeatureFromString(hdev, "AutoFunctionAOISelector", "AOI1");
CHECK(errRes);
/* Enable the 'Intensity' auto function (Gain Auto + Exposure Auto) */
/* for the auto function ROI selected */
errRes = PylonDeviceSetBooleanFeature(hdev, "AutoFunctionAOIUsageIntensity", 1);
CHECK(errRes);
/* Enable Exposure Auto by setting the operating mode to Continuous */
errRes = PylonDeviceFeatureFromString(hdev, "ExposureAuto", "Continuous");
CHECK(errRes);

# Set the Exposure Auto auto function to its minimum lower limit
# and its maximum upper limit
minLowerLimit = camera.AutoExposureTimeLowerLimitRaw.Min
maxUpperLimit = camera.AutoExposureTimeUpperLimitRaw.Max
camera.AutoExposureTimeLowerLimitRaw.Value = minLowerLimit
camera.AutoExposureTimeUpperLimitRaw.Value = maxUpperLimit
# Set the target brightness value to 128
camera.AutoTargetValue.Value = 128
# Select auto function ROI 1
camera.AutoFunctionAOISelector.Value = "AOI1"
# Enable the 'Intensity' auto function (Gain Auto + Exposure Auto)
# for the auto function ROI selected
camera.AutoFunctionAOIUsageIntensity.Value = True
# Enable Exposure Auto by setting the operating mode to Continuous
camera.ExposureAuto.Value = "Continuous"

其他相机#

C++ (Native)C++ (Generic)C#C (Generic)Python

// Set the Exposure Auto auto function to its minimum lower limit
// and its maximum upper limit
double minLowerLimit = camera.AutoExposureTimeLowerLimit.GetMin();
double maxUpperLimit = camera.AutoExposureTimeUpperLimit.GetMax();
camera.AutoExposureTimeLowerLimit.SetValue(minLowerLimit);
camera.AutoExposureTimeUpperLimit.SetValue(maxUpperLimit);
// Set the target brightness value to 0.6
camera.AutoTargetBrightness.SetValue(0.6);
// Select auto function ROI 1
camera.AutoFunctionROISelector.SetValue(AutoFunctionROISelector_ROI1);
// Enable the 'Brightness' auto function (Gain Auto + Exposure Auto)
// for the auto function ROI selected
camera.AutoFunctionROIUseBrightness.SetValue(true);
// Enable Exposure Auto by setting the operating mode to Continuous
camera.ExposureAuto.SetValue(ExposureAuto_Continuous);

INodeMap& nodemap = camera.GetNodeMap();
// Set the Exposure Auto auto function to its minimum lower limit
// and its maximum upper limit
double minLowerLimit = CFloatParameter(nodemap, "AutoExposureTimeLowerLimit").GetMin();
double maxUpperLimit = CFloatParameter(nodemap, "AutoExposureTimeUpperLimit").GetMax();
CFloatParameter(nodemap, "AutoExposureTimeLowerLimit").SetValue(minLowerLimit);
CFloatParameter(nodemap, "AutoExposureTimeUpperLimit").SetValue(maxUpperLimit);
// Set the target brightness value to 0.6
CFloatParameter(nodemap, "AutoTargetBrightness").SetValue(0.6);
// Select auto function ROI 1
CEnumParameter(nodemap, "AutoFunctionROISelector").SetValue("ROI1");
// Enable the 'Brightness' auto function (Gain Auto + Exposure Auto)
// for the auto function ROI selected
CBooleanParameter(nodemap, "AutoFunctionROIUseBrightness").SetValue(true);
// Enable Exposure Auto by setting the operating mode to Continuous
CEnumParameter(nodemap, "ExposureAuto").SetValue("Continuous");

// Set the Exposure Auto auto function to its minimum lower limit
// and its maximum upper limit
double minLowerLimit = camera.Parameters[PLCamera.AutoExposureTimeLowerLimit].GetMinimum();
double maxUpperLimit = camera.Parameters[PLCamera.AutoExposureTimeUpperLimit].GetMaximum();
camera.Parameters[PLCamera.AutoExposureTimeLowerLimit].SetValue(minLowerLimit);
camera.Parameters[PLCamera.AutoExposureTimeUpperLimit].SetValue(maxUpperLimit);
// Set the target brightness value to 0.6
camera.Parameters[PLCamera.AutoTargetBrightness].SetValue(0.6);
// Select auto function ROI 1
camera.Parameters[PLCamera.AutoFunctionROISelector].SetValue(PLCamera.AutoFunctionROISelector.ROI1);
// Enable the 'Brightness' auto function (Gain Auto + Exposure Auto)
// for the auto function ROI selected
camera.Parameters[PLCamera.AutoFunctionROIUseBrightness].SetValue(true);
// Enable Exposure Auto by setting the operating mode to Continuous
camera.Parameters[PLCamera.ExposureAuto].SetValue(PLCamera.ExposureAuto.Continuous);

/* 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 */
double minLowerLimit = 0;
double maxUpperLimit = 0;
/* Set the Exposure Auto auto function to its minimum lower limit */
/* and its maximum upper limit */
errRes = PylonDeviceGetFloatFeatureMin(hdev, "AutoExposureTimeLowerLimit", &minLowerLimit);
CHECK(errRes);
errRes = PylonDeviceGetFloatFeatureMax(hdev, "AutoExposureTimeUpperLimit", &maxUpperLimit);
CHECK(errRes);
errRes = PylonDeviceSetFloatFeature(hdev, "AutoExposureTimeLowerLimit", minLowerLimit);
CHECK(errRes);
errRes = PylonDeviceSetFloatFeature(hdev, "AutoExposureTimeUpperLimit", maxUpperLimit);
CHECK(errRes);
/* Set the target brightness value to 0.6 */
errRes = PylonDeviceSetFloatFeature(hdev, "AutoTargetBrightness", 0.6);
CHECK(errRes);
/* Select auto function ROI 1 */
errRes = PylonDeviceFeatureFromString(hdev, "AutoFunctionROISelector", "ROI1");
CHECK(errRes);
/* Enable the 'Brightness' auto function (Gain Auto + Exposure Auto) */
/* for the auto function ROI selected */
errRes = PylonDeviceSetBooleanFeature(hdev, "AutoFunctionROIUseBrightness", 1);
CHECK(errRes);
/* Enable Exposure Auto by setting the operating mode to Continuous */
errRes = PylonDeviceFeatureFromString(hdev, "ExposureAuto", "Continuous");
CHECK(errRes);

# Set the Exposure Auto auto function to its minimum lower limit
# and its maximum upper limit
minLowerLimit = camera.AutoExposureTimeLowerLimit.Min
maxUpperLimit = camera.AutoExposureTimeUpperLimit.Max
camera.AutoExposureTimeLowerLimit.Value = minLowerLimit
camera.AutoExposureTimeUpperLimit.Value = maxUpperLimit
# Set the target brightness value to 0.6
camera.AutoTargetBrightness.Value = 0.6
# Select auto function ROI 1
camera.AutoFunctionROISelector.Value = "ROI1"
# Enable the 'Brightness' auto function (Gain Auto + Exposure Auto)
# for the auto function ROI selected
camera.AutoFunctionROIUseBrightness.Value = True
# Enable Exposure Auto by setting the operating mode to Continuous
camera.ExposureAuto.Value = "Continuous"

您也可以使用 pylon Viewer 轻松设置参数。