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Vignetting Correction(pylon Viewer)#

The Vignetting Correction feature in the pylon Viewer allows you to remove vignetting artifacts with a single click.

The Vignetting Correction feature is available on selected ace U and ace L models (GigE and USB 3.0) and on boost CXP-12 cameras.

仕組み#

ビネットとは、画像の中心と比較して、画像の隅を暗くなることを意味します。これはデジタル撮像によく見られる現象で、センサーの端にある画素に十分な光が届かない場合に発生します。例えば、画像の円がセンサーのサイズに対して小さすぎる、または光がセンサーの中心には直角に当たるが、隅の方には直角に当たらないなどの理由で発生することがあります。つまり、エッジの画素のグレー値が低くなります。

To remove these vignetting artifacts, the Vignetting Correction feature uses an algorithm that calculates a multiplier to bring the lower-than-expected gray values up to normal levels. The correction data is saved in the camera and can also be downloaded to use it on a different camera. Use the File Access option in the Camera menu to do this.

Performing Vignetting Correction#

情報

  • 最適な結果を得るには、補正データを作成する前に、光源の初期値やガンマなどの非線形機能をすべて無効にしてください。これらの機能は、あとで再度有効にすることができます。
  • カラーカメラでは、補正データを作成する前にベイヤーピクセルフォーマットを選択します。補正データを作成したら、任意のピクセルフォーマットを選択できます。
  • ビネット補正を実行するときは、生成された基準画像の隅の部分が中央部より適度に暗くなっていることが重要です。
  • ビネットは、使用するレンズ、口径、および焦点距離の影響を受けます。レンズ、口径、または焦点距離を変更する場合は、ビネット補正データの新しいセットを作成する必要があります。

To perform vignetting correction:

  1. Open the camera if you have not already done so.
  2. Select a Bayer pixel format.
  3. Place a white sheet of paper in the camera's field of view.
    This allows for a homogeneous illumination of the scene.
  4. Stop continuous image acquisition if it is currently enabled.
  5. Click Camera > Vignetting Correction.
    The algorithm creates the correction data and captures an image with the correction data applied.

Messages about the result will be displayed in the Message Log pane. Among other information, this will give you an error value. This is an indication of the degree of correction achieved. The closer the error value is to zero, the more effective the vignetting correction has been.

Downloading and Uploading Vignetting Correction Data#

You can download vignetting correction data from a camera and upload it to a different camera.

To download vignetting correction data:

  1. Perform vignetting correction as described above.
  2. On the camera that you have performed the vignetting correction on, click Camera > File Access.
    The camera must be open.
  3. In the Camera File Access dialog, select Vignetting Correction in the drop-down list.
  4. Click Download and specify the desired location.
  5. Enter a file name, including a file extension, e.g., .txt, and close the dialog.

To upload vignetting correction data:

  1. On the camera on which you want to upload the correction data, click Camera > File Access.
    The camera must be open.
  2. In the Camera File Access dialog, select Vignetting Correction in the drop-down list.
  3. Click Upload and navigate to the location where you saved the correction data file.
  4. Select the file and click Upload.

To apply the correction data on another camera, execute the VignettingCorrectionLoad command.

情報

  • You should only upload vignetting correction data on cameras with identical specifications to the one on which you created the vignetting correction data, e.g., the sensor size must be the same.
  • Bear in mind that there is a certain variance between individual cameras and lenses, i.e., correction data created on one camera may not completely remove vignetting artifacts on another camera.
  • If the upload fails, the VignettingCorrectionMode parameter in the Features pane will be disabled. If this happens, create a new set of vignetting correction data and repeat the procedure.