Tuning the Luma Feature

This section describes how to tune the Luma feature to control the luma calculation submodule of LTM within a DC9400.

Before you begin

Make sure:

The details view contains the Luma table for LTM.
To tune this feature, you need to choose DC9400 > LTM > Luma in the Features view. For more details, see Tuning a DC9400 Feature.

Figure 1. Luma Table for LTM
A VTunerServer is accessible.
For information about how to set up a connection to a VTunerServer, see Setting Up a Connection to a VTunerServer.

Procedure

From the LTM Luma Mode drop-down list, select one of the following options to specify the luma calculation mode:
- VS_DPU_LUMA_GRAY: the Y component is obtained in gray-oriented mode using the following formula:
  $Y_{gray} = (\begin{matrix} Coef0 & Coef1 & Coef2 \end{matrix}) (\begin{matrix} R_{input} \\ G_{input} \\ B_{input} \end{matrix})$
  where Coef0, Coef1, and Coef2 need to be specified.
- VS_DPU_LUMA_LIGHTNESS: the Y component is obtained in lightness-oriented mode using the following formula:
  $Y_{lightness} = (1 - lightness_weight) \times Min (R_{input}, G_{input}, B_{input}) + lightness_weight \times Max (R_{input}, G_{input}, B_{input})$
  where lightness_weight needs to be specified.
- VS_DPU_LUMA_MIXED: the Y component is obtained in gray/lightness-balanced mode using the following formula:
  $Y_{mixed} = Y_{gray} \times gray_weight + Y_{lightness} \times (1 - gray_weight)$
  where gray_weight needs to be specified in addition to Coef0, Coef1, Coef2, and lightness_weight.
Next to LTM Luma Coef, click View/Edit this Table and edit the coefficients and weights for luma calculation in the prompted dialog.
The columns in the LTM Luma Coef table are described as follows:
- Coef 0, Coef 1, and Coef 2: the coefficients used to calculate Y_gray
- Coef 3: the lightness_weight used to calculate Y_lightness
- Coef 4: the gray_weight used to calculate Y_mixed
You can use one of the following methods to update the coefficients and weights in the LTM Luma Coef table:
- Double-click and edit a cell in the table to update a single coefficient or weight.
- Click Edit and update the coefficients and weights in the prompted Edit Table dialog.
  The coefficients and weights must be specified in the same order as the table columns and separated by a comma (,).
- Click Export to export the coefficients and weights to a .csv file, edit the file, and then import the updated coefficients and weights from the .csv file.
  The order of the coefficients and weights in the exported .csv file is the same as that in the table.

Results

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