Tuning the 3DLUT Feature

This section describes how to tune the 3DLUT feature to control the three-dimensional lookup table (3D LUT) of a DC9400.

Before you begin

Make sure:
  • The details view shows the settings of the 3DLUT feature for a DC9400 project.

    To tune the 3DLUT feature, you need to choose DC9400 > 3DLUT > Whole Image, ROI 0, or ROI 1 in the Features view. If only one ROI is needed, make sure that ROI 0 is used for setting the 3D LUT. For more details, see Tuning a DC9400 Feature.

    Figure 1. Details View When Whole Image under 3DLUT Is Selected

  • The VTunerClient is connected to a VTunerServer that works with a DC9400.

    For information about how to set up a connection to a VTunerServer, see Setting Up a Connection to a VTunerServer.

About this task

You can tune the 3DLUT feature for either the whole image or in a maximum of two regions of interest (ROIs).
  • For the whole image, the 3D LUT consists of 17x17x17 control points.
  • For each ROI, the 3D LUT consits of 9x9x9 control points.

Procedure

  1. In the upper-left corner, select the Enable check box to enable the 3D LUT module for the whole image, ROI 0, or ROI 1.
  2. In the Coordinates text box, enter the chromaticity coordinates of the current calibration node being loaded.
  3. (Only for ROI 0 and ROI 1) In the Region(XYWH) text box, specify a rectangle in the image as the ROI in which the 3D LUT takes effect.
    The rectangle must be specified in the X, Y, W, H format, where:
    • X: the X coordinate of the upper-left corner of the rectangle.
    • Y: the Y coordinate of the upper-left coner of the rectangle.
    • W: the width of the rectangle.
    • H: the height of the rectangle.
  4. Select the Basic Calibration or Fine Tuning tab.
    • If the Basic Calibration tab is selected, the 3D LUT is generated using standard checkers.
    • If Fine Tuning is selected, the 3D LUT is generated by mapping specified input colors to target colors.
  5. If the Basic Calibration tab is selected, perform the following steps:
    1. To the right of Target Patch File, click the Open button.
    2. In the prompted Pick Color Checker window, select 24-patch, 140-patch, or User Defined from the Color Checker Type drop-down list.
      Figure 2. Pick Color Checker Window

    3. If 24-patch or 140-patch is selected for Color Checker Type, perform the following steps:
      1. On the Input Patch File page, click the Browse button and select the input color checker image.
        Figure 3. Input Patch File Page for 24-Patch Color Checker

      2. In the displayed image, click the center of the color patch at each corner of the color checker to explicitly specify the color checker.

        The average color of each patch in the color checker is calculated and used as the patch color.

      3. (Optional) To change a color checker corner, click the corresponding mark to remove it and then click the center of a color patch to mark it as the new color checker corner.
      4. Under Rotate, drag the slider to rotate the image.
      5. Click Next.
      6. On the Target Patch File page, click the Browse button and select the target color checker image.
        Figure 4. Target Patch File Page for 24-Patch Color Checker

      7. In the displayed image, click the center of the color patch at each corner of the color checker by referring to Step 5.c.ii and Step 5.c.iii.
      8. Under Rotate, drag the slider to rotate the image.
      9. Click Next.
    4. If User Defined is selected for Color Checker Type, perform the following steps:
      1. On the Input Patch File page, click the Browse button and select the .csv file that describes the R, G, and B values of each patch in the input color checker.
        Figure 5. Example CSV File

        Figure 6. Input Patch File Page for User-Defined Color Checker

      2. Click Next.
      3. On the Target Patch File page, click the Browse button and select the .csv file that describes the R, G, and B values of each patch in the target color checker.
        Figure 7. Target Patch File Page for User-Defined Color Checker

      4. Click Next.
    5. On the Advance page, modify the weight of each color for generating the 3D LUT and click Finish.
      Figure 8. Advance Page of the Pick Color Checker Window

      Then, on the Basic Calibration tab of the details view:
      • The Summary table shows the global maximum and average Delta C and Delta E.
      • The Attributes table shows the following attributes of each color patch: index, weight, input, target, and optimized colors, and Delta C and Delta E before and after optimization.
      Figure 9. Details View with Basic Calibration Settings When Precision Mode under 3DLUT Is Selected

    6. (Optional) To update the weight of a color patch, double-click the corresponding cell in the Weight column, enter the target weight value, and press Enter.

      The weight controls how close the input is to the target. The input and the target are closer if the weight is set to a greater value. The valid range of the weight is from 0.0 to 2.0, inclusive. The default value is 1.0.

  6. If the Fine Tuning tab is selected, perform the following steps:
    Figure 10. Details View with Fine Tuning Settings When Precision Mode under 3DLUT Is Selected

    1. To the right of Input Image File, click the Open button and select the input image.
    2. To the right of Target Image File, click the Open button and select the target image.
    3. Add each sample patch as follows:
      1. In the Input Sample Size spin box of the Sample Setting section, specify the sample patch size of the input image.
      2. Select the sample input color by double-clicking a proper position in the input image.

        Then, the R, G, and B values of the sample input color is automatically filled in the Input section under Sample Detail.

      3. In the Target Sample Size spin box of the Sample Setting section, specify the sample patch size of the target image.
      4. Select the sample target color by double-clicking a proper position in the target image.

        Then, the R, G, and B values of the sample target color is automatically filled in the Target section under Sample Detail.

      5. In the Weight text box of the Sample Detail section, enter the weight of the sample color.
      6. Click Add Sample.

        Then, the attributes of the sample patch are added to the Attributes table. The attributes include index, weight, input color, target color, optimized color, and Delta C and Delta E before and after optimization.

    4. (Optional) To update the weights of all sample patches to the same value, enter the value in the Total Weight text box.
  7. In the upper-right corner, click the Create 3D LUT button to re-generate a 3D LUT with the modified color weights.

Results

  • The tuning results are printed in the Console view in real time.
  • The image displayed on the VTunerServer side is updated.