Note ● Before starting the acquisition you can call (Page 26 / 388) Machine Vision Camera SDK (C)_Developer Guide_V4.0.0

Machine Vision Camera SDK (C) Developer Guide

Note

● Before starting the acquisition, you can call MV_CC_SetImageNodeNum to set the number of

image buffer nodes. When the number of obtained images is larger than this number, the

earliest image data will be discarded automatically.

● For original image data, you can call MV_CC_ConvertPixelType to convert the image pixel

format, or you can call MV_CC_SaveImageEx2 to convert the image to JPEG or BMP format

and save as a file.

6. Perform one of the following operations to acquire images.

- Call MV_CC_GetOneFrameTimeout repeatedly in the application layer to get the frame data

with specified pixel format.

- Call MV_CC_GetImageBuffer in the application layer to get the frame data with specified pixel

format and call MV_CC_FreeImageBuffer to release the buffer.

Note

● When getting the frame data, the application program should control the frequency of calling

this API according to the frame rate.

● The differences of above two image acquisition methods are:

MV_CC_GetImageBuffer should be used with MV_CC_FreeImageBuffer in pairs, the data

pointer of pstFrame should be released by MV_CC_FreeImageBuffer .

Compared with MV_CC_GetOneFrameTimeout , MV_CC_GetImageBuffer is more efficient,

and its stream buffer is allocated by SDK, while the stream buffer of

MV_CC_GetOneFrameTimeout should allocated by the developer.

● The above two methods and the method of acquiring image in callback function cannot be

used at the same time.

● The pData returns an address pointer, it is recommended to copy the data of pData to create

another thread.

7. Optional: Call MV_CC_DisplayOneFrame to input the window handle and start displaying.

8. Call MV_CC_StopGrabbing to stop the acquisition or stop displaying.

9. Call MV_CC_CloseDevice to close the device.

10. Call MV_CC_DestroyHandle to destroy the handle and release resources.

3.2 Get Image in Callback Function

The API MV_CC_RegisterImageCallBackEx is provided for registering callback function. You can

customize the callback function and the obtained image will automatically called back. This

method can simplify the application logic.