Sequences

A sequence is a special type of ImageWarp's document which contains multiple images. It usually represents a series of related images taken at different points in time and space. Sequences can be used in a wide variety of applications such as motion analysis, volume measurements, intensity analysis through z-series, absorption and radioactivity measurements. Images in a sequence are stored along with corresponding time intervals allowing for playing the sequence at a variable frame rate. ImageWarp treats sequences as a special case of the regular images, placing them into the global queue of image frames. That means that the image processing functions can access sequences by their frame numbers just like static images. All the basic commands applicable to images can be applied to sequences as well.

A sequence can contain images of any type supported by ImageWarp. To capture a sequence from the video device, use the Capture Video command from the Acquire menu or the equivalent GrabSeq function in a script. You can select the number of video frames to be captured and the time interval between them. You can also create a new sequence by converting a static image into a single-frame animation (see Convert to Sequence) and then appending it with additional frames. Refer to ImageWarp Language Reference for more details.

You can save a sequence in a GIF, IWD, or AVI file. Since GIF format only supports 8 bits per pixel, all the frames in the sequence will be automatically converted into 8-bit format (palettized or grayscale). If you are saving the sequence in the AVI file, make sure that the codec selected supports the bit depth of the sequence. Grayscale sequences can also be stored in TIFF and FTS files.

When you use the drawing tools or processing commands on a sequence, they will be applied only to the visible image (frame) of the sequence. One exception is the Duplicate command that will create a copy of the whole sequence. If a rectangular selection is active on a sequence, the Duplicate command will retrieve the selected area of the sequence and place it in a new image frame as a sequence.

If an image frame contains a sequence, the Sequencer Toolbar will appear at the bottom of the frame with the following buttons:

Play   Plays the sequence forward by automatically displaying consecutive frames.   Stop   Stop sequence play so that the stepping controls can be used.   Play backward   Plays the sequence backward.   StepBack   Steps the sequence to the previous frame. If the beginning of the sequence is reached, the stepping will wrap around.   StepForward   Steps the sequence to the next frame. If the end of the sequence is reached, the stepping will wrap around.   Frame Slider   Allows you to quickly move to an arbitrary frame in the sequence.   12 Frame Box   Reports and sets the current frame number.

In addition, a popup menu with the most frequently used commands may be obtained by placing the mouse cursor over a sequence frame and clicking the right button.