Metrologic IS4910 Series, Руководство программиста

Страница: 17 / 42

11
C
AMERA
S
UPPORT
L
IBRARY
C
AM
L
IB
Clocks
The IS4910 camera has the master and pixel clocks. The master clock provides the image sensor with
the input clock. The pixel clock used by the host system to sample the sensor data.
The master clock is provided by the onboard oscillator and its frequency is 48 MHz. Allowed pixel clock
frequencies on PXA270 platform are: 12 and 24 MHz. By default, if not specified otherwise in the IS4910
device driver initialization file VuQuest2D.ini, the pixel clock frequency is set to the maximum 24 MHz.
If the camera is running in the video mode, it must be stopped before changing this property.
camSetClocks
This function sets the master and pixel clocks in Hertz.
Prototype :
int camSetClocks (int cam_handle, long pclk , long mclk );
Parameters :
cam_handle - [in] handle to the camera device returned by the camOpen function.
pclk - [in] pixel clock frequency in Hz.
mclk - [in] should be 0.
Return Value:
0: Success; -1: Failure
camGetClocks
This function returns the master and pixel clocks in Hertz.
Prototype :
int camGetClocks (int cam_handle, long * pclk , long * mclk );
Parameters :
cam_handle - [in] handle to the camera device returned by the camOpen function.
pclk - [out] pixel clock frequency in Hz.
mclk - [out] should be NULL.
Return Value:
0: Success; -1: Failure
Window of Interest
The window of interest (WOI) is the area within the field of view of the camera where image processing
and barcode decoding operations are performed. By default, the WOI is set to equal the entire field of
view of the camera, which 1280 x 960 (1280 columns by 960 rows). Note that numeration of rows and
columns starts from 0, meaning that the very first pixel at the top left corner of the field of view has
coordinates (0, 0). Note also that every pixel is an 8-bit value, ranging from 0 to 255.
By default, if not specified otherwise in the IS4910 device driver initialization file VuQuest2D.ini, the
window of interest covers the entire field-of-view of the sensor, which is 1280 x 960 (1280 columns by
960 rows).
If the camera is running in the video mode, it must be stopped before changing this property.