User manual

Small Vision System User Manual 21
2.2 Storing, Saving, and Loading Stereo Data
smallv provides a basic facility for loading and saving stereo data streams. The file load and store
functions are part of the SVS library, and their source code is included. smallv exercises these
functions, and provides a memory buffer for storing live stereo video.
There are two basic types of storage/playback available. The first, video storage, is meant to save a
video sequence of stereo images (including color information). Images from live video streaming are
captured to an internal buffer of 200 frames. These frames can be replayed and stored.
A second type of storage is still image storage. In this mode, a single frame is stored to a file. The
video storage buffer is not involved in this process, and an arbitrary number of such stills can be saved.
2.2.1 Stereo Video Storage
smallv has an internal buffer capable of holding 200 stereo pairs (frames). Depending on the size
of the images and the amount of memory on the machine, a video sequence of frames can be captured to
physical memory without slowing down video capture.
The buffer can be filled from a previously-saved file set, or from live video input. The buffer can also
be written out to a file set, and used as the source for stereo processing in smallv.
The video buffer is controlled from the Video Buffer window, accessed via the menu bar (Figure
2-7).
When the input source is the buffer, the acquisition mode controls (Continuous, Single,
Freeze) control the processing of the buffer frames (Section 2.1.8). The frame control can also be used
to go to an individual frame when in Single acquisition mode.
The Record button controls the input of live video into the buffer. Clear clears the buffer and
resets it to frame 0. Activating the Record button starts the input of live video frames into the buffer.
The source must be set to Video; either Continuous or Single mode may be used. Frames are
stored sequentially until the buffer is full. Pressing Record again will also turn off acquisition before the
buffer is full.
As an example, to capture a short video sequence and replay it, perform the following steps.
1. Start acquiring live video in continuous mode.
2. Clear the buffer (Clear button).
3. Start buffer storage (Record button).
4. After a short period, stop buffer storage (Record button).
5. Change from Video to Buffer source.
At this point, the short segment that is in the buffer can be replayed as a short continuous loop. The
Figure 2-7 Video buffer controls.