HALCON Frame Grabber Interface for GINGA++ Boards

This document provides information about the sequence grabbing mode that can be used by the HALCON Ginga++ interface. The latest revision of this interface can be downloaded from the Support Area of the LinX WWW server. In case of installation problems please send e-mail (techimage@linx.jp) or fax (81-45-979-0732) to LinX technical support center.

Sequence Grabbing Mode

The principle idea of this grabbing mode is that the image frames are stored sequentially to several frame buffers, which are allocated in system memory in advance. With the use of only one grab command like grab_image the specified number of frames are grabbed at once.

Note that the frame rate for grabbing can be adjusted either automatically or dynamically according to the PCI load by setting the grabbing frequency.

Parameters for set_framegrabber_param():

	'capture_frequency'	'Capture=x Drop=y' (1≤x≤15, 0≤y≤15)	Specify the grabbing frequency to adjust the desired frame rate automatically and dynamically according to the PCI load. The frames specified by x are grabbed sequentially. After that, the grabbing is suspended for the next y frames. This parameter is effective only in sequence or continuous grabbing mode. Default: value specified in the camera file.
	'num_buffers'	2, 3, 4, ...	The number of allocated frame buffers is specified in case of sequence grabbing or continuous grabbing mode. The maximum number of frame buffers is limited by system memory size. Note that 'num_buffers' must be set before enabling the sequence grabbing mode!
	'sequence_grabbing'	'enable', 'disable'	Activate/deactivate sequence grabbing mode. Default: 'disable'.

Example

  num_buffers:       5
  capture_frequency: 'Capture=2 Drop=1'

Limitation

The sequence grabbing mode can not be combined with the software trigger (shot grabbing) mode!

Sample Program

close_all_framegrabbers ()
NumBuffers := 5
open_framegrabber ('Ginga++', 1, 1, 0, 0, 0, 0, 'default', 8, 'default', -1, 'default', 'jai/CVM40_NI_NORM', 'default', 0, -1, FGHandle)
set_framegrabber_param (FGHandle, 'num_buffers', NumBuffers)
set_framegrabber_param (FGHandle, 'sequence_grabbing', 'enable')
set_framegrabber_param (FGHandle, 'capture_frequency', 'Capture=2 Drop=1')
set_framegrabber_param (FGHandle, 'volatile', 'enable')
dev_close_window ()
dev_open_window (0, 0, 640, 480, 'black', WindowHandle)
stop ()
* Sequential image, whose number is specified by NumBuffers, can be  
* grabbed into channel by the following one operator:
grab_image (Image, FGHandle)
stop ()
count_channels (Image, Channels)
for i := 1 to Channels by 1
  access_channel (Image, Image1, i)
  dev_display (Image1)
endfor