Calibration with StreamImage

Programming Questions .Net API
1

I try to read out the data of my camera using the StreamImage Code sample, as well as the calibration code sample. But I never get any data, which is correctly calibrated. Here is the code I use:

var stream = camera.Stream;

NodeMap nm = camera.NodeMaps[NodeMapNames.Device];
NodeMap cameraNodeMap = camera.NodeMaps[NodeMapNames.Device];

// get calibration file from camera
var files = cameraNodeMap.GetAvailableFiles();
if (files.Contains("UserData"))
    cameraNodeMap.DownloadFile($@"D:\VermessungErgebnisse\CalibrationFile.dat", "UserData");
            
stream.Start();
try
{
    Console.WriteLine("Start streaming");
    while (true)
    {
        using (StreamImage image = stream.Wait())
        {                                           
            var cloud = Calibrator3D.FromFile($@"D:\VermessungErgebnisse\CalibrationFile.dat")
                          .CreatePointCloud<Point3Dd>(image);
            var fileName = DateTime.Now.ToFileTime();                     
            cloud.Save($@"D:\VermessungErgebnisse\Camera\{fileName}.xyz");            
        }
    }
}
finally
{
    stream.Stop();
}

After calibration, the data from the camera is still in 2D, but bent like an “U”. If I use the calibration method FromFactors(1,1,1), I get a relative correct data.

What am I doing wrong?

2

Hi Michael,

taking a look at your code I don’t see why this shouldn’t work.

If a calibration seems to be not valid it can have multiple possible reasons:

  • how did you set the output images of the camera. Did you enable only DC2? If not, you need to decode the interleaved information first.
  • do the calibration parameters from the calibration file match the acquisition parameters in the camera? In specific the following parameters should be checked:
    - subpixels (rangeScale)
    - encoder resolution (Sy)
    –> since the .dat file is not readable, please store it in the .xml format (using the CXExplorer of the manufacturer). This way you can check or adapt the parameters. A more automated way to read the parameters is to store the calibration file after downloading it from the camera in CVB’s calibrator format (.json).
  • did you set the AbsOffsetPos parameter in the camera to true?
  • slight inaccuracies can be a result of using the sensor in a cold state. It is recommended to heat up the sensor for at least 1h before doing precise measurements
3

Hi Moli,

thanks for the reply.

For my test I only enabled DC2.

In my code I read the parameters directly from the camera. Is there some way, that they are different (e.g. subpixels or encoder resultion)?

SubPixels is 6 in configuration and rangeScale is 0.015625. Encoder Resolution is 1, where can I change this parameter in the configuration of the camera?

AbsOffsetPos is true.

I would love to enclose the XML and config file of the camera, but I seems I can´t yet.

EDIT: Here are the contents of the files.

JSON:

Summary

{
“cx3d”: {
“-xmlns:xsi”: “http://www.w3.org/2001/XMLSchema-instance”,
“-MajorVersion”: “1”,
“-MinorVersion”: “0”,
“-xsi:noNamespaceSchemaLocation”: “cx3d.xsd”,
“CalibCase3d”: {
“-id”: “cal0”,
“name”: “C5-1600CS19-500SN21311685”,
“dateTime”: “2019-06-21-12-49-58”,
“creator”: “AT-Automation Technology GmbH”,
“description”: “Factory Calibration”,
“target”: “2”,
“sensorSize”: “1600 1088”,
“fov”: “0 0 0 0 0 0”,
“roc”: “0 0 0 0”,
“intrinsic”: {
“model”: “65537”,
“rangeScale”: “0.015625”,
“sensorRoi”: “0 0 1600 63”,
“sensorR”: “0 0 0”,
“pixelSize”: “0 0”,
“f”: “0”,
“cp”: “0 0”,
“L”: {
“rows”: “1”,
“cols”: “0”,
“dt”: “d”
},
“P”: {
“rows”: “3”,
“cols”: “3”,
“dt”: “d”,
“data”: “1.015830039978027 0.001321549993008375 -798.7839965820313 0.001118979998864233 3.102370023727417 -1689.949951171875 -3.28493001688912e-06 0.0040095797739923 1”
},
“C”: {
“rows”: “15”,
“cols”: “2”,
“dt”: “d”,
“data”: “0.08127669990062714 0.0766431987285614 0.9864400029182434 0.0003397869877517223 -0.0001088709977921098 0.9906460046768188 1.117379997594981e-05 -3.249710061936639e-06 -5.300819793774281e-06 -1.672799953666981e-05 -1.655169967307302e-06 1.213910036312882e-05 -1.678910011015944e-09 3.978639995239064e-07 5.936509950288382e-08 1.882870082070554e-09 3.556399974513624e-07 -3.453709984668762e-09 -2.127370057891653e-09 4.710160084187009e-08 4.132680031521119e-10 -1.571999995453321e-11 -7.847960020561373e-13 4.245669926739026e-10 4.458389907258109e-11 -1.880020011196804e-12 -4.103020007084623e-12 1.499100010793342e-10 1.3546700219913e-11 3.782259921925046e-11”
}
},
“extrinsic”: {
“Sy”: “1”,
“Sxy”: “0”,
“Szy”: “0”,
“T”: “0 0 0”,
“R”: “0 0 0”
},
“metric”: {
“offset”: “0 0 0”,
“scale”: “1 1 1”,
“invalidDataValue”: “0”
},
“accuracyStat”: {
“rows”: “4”,
“cols”: “3”,
“dt”: “d”,
“data”: “0 0 0 0 0 0 0 0 0 0 0 0”
},
“lensCorrStat”: {
“rows”: “1”,
“cols”: “3”,
“dt”: “d”,
“data”: “0 0 0”
}
}
}
}

Config:

Summary 
{05D8C294-F295-4dfb-9D01-096BD04049F4}

GenApi persistence file (version 3.1.0)
Device = AutomationTechnology::CX_CMV_GigE – AT generic GigEVision interface for CX-CMV Series – Device version = 2.5.0 – Product GUID = F9138771-8EF5-4710-9427-63FE3A7C2101 – Product version GUID = F3B5B91B-A333-4460-8BD9-E38EE40C64FD
CameraMode CenterOfGravity
FIR 1
ProfileTriggerMode EncoderResolverInterfaceRS422
EnableDC2 1
EnableDC1 0
Width 1600
PixelFormat Mono16
ReverseX 0
ReverseY 0
OffsetX 0
ChunkModeActive 0
ChunkModeSelector OneChunkPerFrame
AcquisitionMode Continuous
AcquisitionFrameCount 1
MultiSlopeKneePointCount 1
MultiSlopeKneePointSelector 1
MultiSlopeExposureLimit 99
MultiSlopeKneePointSelector 2
MultiSlopeExposureLimit 99
MultiSlopeKneePointSelector 1
MultiSlopeKneePointSelector 1
MultiSlopeSaturationThreshold 60.3175
MultiSlopeKneePointSelector 2
MultiSlopeSaturationThreshold 49.2063
MultiSlopeKneePointSelector 1
ExposureTime 500
NumAois 1
AoiSelector 1
AoiSelector 1
AoiHeight 63
AoiSelector 1
AoiSelector 1
AoiOffsetY 530
AoiSelector 1
AoiSelector 1
AoiThreshold 120
AoiSelector 1
FIR 1
FIRCoef SG9
FIRGain 1
FIRCorrection 0
CameraMode CenterOfGravity
ProfilesPerFrame 1000
AbsOffsetPos 1
NumSubPixel 6
TrshFirstFalling 0
TrshFirstZeroCrossing 0
MinThrshValidation 1
PosValidationEn 0
ClearInvalidPos 0
ValidationWidthMin 0
ValidationWidthMax 1087
ValidationSumMin 0
ValidationSumMax 65535
AoiTrackingEnable 0
AoiSearchEnable 0
AoiSearchMinNumPixel 100
AoiSearchHeight 1088
AoiSearchOffsetY 0
AoiSearchAlgorithm Mean
FramePeriod 737
LineStartSyncTrigger 1
GainPGA Gain2
GainADC 40
BlackLevelOffset 16323
Vramp1 109
Vramp2 109
BlackSunControl 98
FOT 10
DummyRows 1
VresLow 64
EnableDC2 1
EnableDC1 0
EnableDC0 0
EnableDC1TrshWidth 0
EnableDC1Width 0
EnableDC1Option 0
EnableDC1Flags 0
EnableDC2TrshSP 0
LightControllerSource ExposureActive
LightBrightnessControlMode Analog
LightBrightness 50
Output1 Out1_SequencerActive
Output2 Out2_IntegrationActive
Output1MinPulseWidth 0
Output2MinPulseWidth 0
Output1Delay 0
Output2Delay 0
Output1Invert 0
Output2Invert 0
SequencerMode StartCameraInput1
ProfileTriggerMode EncoderResolverInterfaceRS422
TriggerDivider 1
TriggerDirectionMode 1
TriggerReverseDirection 1
TriggerSingleChannelMode Disabled
TriggerDividerLoadAtStart 0
ResetTriggerCoordZeroPos Off
TriggerCoordinateCountAlways 1
UseAlternateResolverInputs 0
UseAlternateResolverInputsInverted 0
GevHeartbeatTimeout 3000
GevStreamChannelSelector 0
GevSCPSPacketSize 1500
GevStreamChannelSelector 0
GevStreamChannelSelector 0
GevSCPD 5000
GevStreamChannelSelector 0
EventSelector AcquisitionStart
EventSelector AcquisitionStart
EventNotification Off
EventSelector AcquisitionEnd
EventNotification Off
EventSelector AcquisitionTransferStart
EventNotification Off
EventSelector AcquisitionTransferEnd
EventNotification Off
EventSelector AoiTrackingStart
EventNotification Off
EventSelector AoiTrackingEnd
EventNotification Off
EventSelector AoiSearchFailed
EventNotification Off
EventSelector AutoStartTrigger
EventNotification Off
EventSelector AcquisitionStart

4

In some cases it is possible that users of the AT cameras set the subpixel value within the camera to a different value than the one in the calibration file. This would lead to distorted profiles. However, in your case it is set to 6 subpixels in the camera and calib file. So this seems to be fine.

The encoder resolution can only be set in the calibration file, not in the camera.

Can you please send me the acquired range map + calibration file + settings file per PN? This way I can reproduce the resulting point clouds with static factors and with the calibration.

5

The Solution was, that the driver had “Auto Detect” as output format. I changed it to RAW and now everything works fine.

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