DemodulationMode Property

NI Vision for Visual Basic

DemodulationMode Property

Syntax

CWIMAQQRSearchOptions.DemodulationMode

Data Type

CWIMAQQRDemodulationModes

You can use the following constants with this data type:

  • cwimaqQRDemodulationModeAll—The method tries cwimaqQRDemodulationModeHistogram, then cwimaqQRDemodulationModeLocalContrast and then cwimaqQRDemodulationModeCombined, stopping once one mode is successful.
  • cwimaqQRDemodulationModeAutoDetect—The method will try each demodulation mode and use the one which decodes the QR code within the fewest iterations and utilizing the least amount of error correction.
  • cwimaqQRDemodulationModeCombined—The method uses the histogram of the QR code to calculate a threshold. For cells with pixel values that are sufficiently below or above this threshold, the method will use the threshold to determine if the cell is on or off. If the cell pixel values are close to the threshold, the method will use the cwimaqQRDemodulationModeLocalContrast mode to determine if the cell is on or off. This mode is slower, but works with images that contain a QR code with extremely low cell fill percentages or gross print growth errors.
  • cwimaqQRDemodulationModeHistogram—The method uses a histogram of all of the QR cells to calculate a threshold. This threshold determines if a cell is on or off. This is the fastest mode, but requires images with consistent levels of contrast.
  • cwimaqQRDemodulationModeLocalContrast—The method examines each of the cell's neighbors to determine if the cell is on or off. This mode is slower, but works with images that have inconsistent levels of contrast.

Purpose

Specifies the mode the method should use to demodulate (determine which cells are on and which cells are off) the QR code.

Remarks

The default value is cwimaqQRDemodulationModeAutoDetect.