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Gamma (BCON for MIPI)#

The Gamma camera feature allows you to optimize the brightness of acquired images for display on a monitor.

Using the Feature#

How It Works#

The camera applies a gamma correction value (γ) to the brightness value of each pixel according to the following formula (red pixel value (R) of a color camera shown as an example):

Gamma Correction Formula (Red Pixels)

The maximum pixel value (Rmax) equals, e.g., 255 for 8-bit pixel formats or 1 023 for 10-bit pixel formats.

Configuring Gamma Correction#

To configure gamma correction, set the Gamma parameter to the desired value. The parameter's value range is 0 to ≈4. - Gamma = 1: The overall brightness remains unchanged. - Gamma < 1: The overall brightness increases. - Gamma > 1: The overall brightness decreases.

In all cases, black pixels (brightness = 0) and white pixels (brightness = maximum) will not be adjusted.

Info

If you enable gamma correction and the pixel format is set to a 12-bit pixel format, some image information will be lost. Pixel data output will still be 12-bit, but the pixel values will be interpolated during the gamma correction process.

Additional Parameters#

Depending on your camera model, the following additional parameters are available:

  • BslColorSpace: Allows you to select one of the following gamma correction modes:
    • RGB: No additional gamma correction value is applied.
    • sRGB: The image brightness is optimized for display on an sRGB monitor. A gamma correction value of approximately 0.4 is applied. For more information, see the footnotes in the Specifics section.

Specifics#

Camera Model Additional Parameters
daA2500-60mc Gamma feature not supported
daA2500-60mci BslColorSpacea
daA3840-30mc Gamma feature not supported
daA4200-30mci BslColorSpacea

  1. If the color space is set to sRGB, a gamma correction value of approximately 0.4 is applied, the Gamma parameter becomes read-only, and the Gamma parameter value is ignored.

Sample Code#

// Set the Gamma value to 1.2
camera.Gamma.SetValue(1.2);

INodeMap& nodemap = camera.GetNodeMap();
// Set the Gamma value to 1.2
CFloatParameter(nodemap, "Gamma").SetValue(1.2);

/* 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 */
/* Set the Gamma value to 1.2 */
errRes = PylonDeviceSetFloatFeature(hdev, "Gamma", 1.2);
CHECK(errRes);

You can also use the pylon Viewer to easily set the parameters.