MdigReference()函数

Synopsis

Select digitization reference level.

Format

void MdigReference(DigId, ReferenceType, ReferenceLevel)

MIL_ID DigId;

Digitizer identifier

long ReferenceType;

Reference type

long ReferenceLevel;

Reference level

Description

This function sets (if available) the reference levels used to digitize the analog signal received from an input device (generally a camera). This function is specific to analog input devices. Depending on the type of digitizer and input signal, some reference types are not applicable.

The DigId parameter specifies the identifier of the digitizer on which to set the reference level. An error is generated if the specified digitizer does not support the type of programmable digitization reference levels specified.

The ReferenceType parameter specifies the reference level type to adjust for the specified digitizer. This parameter can be set to one of the following:

M_BLACK_REF

Set the input signal’s digitization black reference level (0).

M_WHITE_REF

Set the input signal’s digitization white reference level
(eg: 0xff for 8-bit digitization).

M_BRIGHTNESS_REF

Set the brightness level for composite input signals.

M_CONTRAST_REF

Set the contrast level for composite input signals.

M_HUE_REF

Set the hue level for composite input signals.)

M_SATURATION_REF

Set the saturation level for composite input signals.

On many digitizers, when using RGB input and setting ReferenceType to M_BLACK_REF or M_WHITE_REF, you can control the reference level of a specific input channel by combining it with one of the following:

M_CH0_REF

Set the reference level on input channel 0.

M_CH1_REF

Set the reference level on input channel 1.

M_CH2_REF

Set the reference level on input channel 2.

M_CH3_REF

Set the reference level on input channel 3.

M_ALL_REF

Set the reference level on all input channels. (This is the default setting).

The ReferenceLevel parameter specifies the level of reference. This parameter can be set to a value between M_MIN_LEVEL and M_MAX_LEVEL, inclusive. The value may be expressed as an integer within this range, or as M_MIN_LEVEL + n or M_MAX_LEVEL – n. If you set this parameter to M_DEFAULT, the reference levels are set to the default levels for the specified digitizer data format.

Note, some digitizers might take a few milliseconds before the reference level stabilizes.

See also

MdigAlloc