Video

Toolbar:

Menu:   View > Video

Script:   showVideo, setVideoPos, setVideoPal, setDisplayRange

Use this command to show or hide the Video window. The Video window displays the live image (video frames) coming from the video device. Unlike the thumbnail Preview in the Capture dialog box, the Video window displays the live video in actual size. Its main purpose is to let the user check the functionality of the video device, evaluate and adjust the video settings, and select the size and location of images to be captured.

If Cut to video frame is selected in Video Preferences, the visible area of the Video window will define the working area for capturing functions. In this case, changing the size of the Video window and scrolling its viewable area will modify the size of the captured images and change the position of the capture area on the virtual video surface. Note that you can pan the content of the Video window not only with the scroll-bars, but also by dragging its client area. The information about the current size and location of the capture area, as well as the frame rate is displayed on the Status Bar.

You can analyze the digital content of the live image by moving the mouse cursor over it and watching the reported pixel values on the status bar, or you can open the Digital Editor which will give you an access to all the pixels in numerical format.

You can use Zoom In and Zoom Out commands to enlarge or reduce the visible size of the live video and images captured from the video device. Changing zoom will not affect the actual size of the video frames or captured images, but only their appearance on the screen. To modify the size of the video frames, use Video Format command. The Local Zoom tool allows for viewing a magnified area of interest of the live image in a separate window.

If the video device is set up to acquire high-bit depth Images (more than 8-bit per channel), the Video window will have Display Range boxes at the bottom. By adjusting the minimum and maximum levels of the display range, you can map a specific intensity range of the live image to the standard 8-bit luminance scale of the display.

The following commands are available from the Video tool bar, located on the left side of the Video window, or from the context menu, activated by the right button click:

Snap   

Captures a single image from the current capture area of the video device. The image is created in the first available image frame. This command gives you a quick and convenient way to capture images. For more advanced capture operations use the Capture command.

Freeze/Unfreeze   

Use this command to toggle the video devise between Freeze and Unfreeze modes. When the video is frozen, the content of Video window remains unchanged and the capture functions will create images from the frozen video frame. A check mark will appear next to the Freeze command in the menu and the button on the video tool bar will remain pressed. To unfreeze the video, apply the same command again.

Trigger   

Use this command apply a software Trigger signal to the video device that is set to the trigger mode. The trigger signal usually initiates an acquisition of a single frame. In the start/stop mode, mostly used by line-scan devices, this command should be used twice: first time to initiate the frame acquisition and second time to finish it. In this case the size of the frame will depend on the time between two consecutive Trigger commands. If the video device is working in the continuous mode, this command will be unavailable.

Source   

Displays the Video Source dialog box.

Format   

Displays the Video Format dialog box

Display   

Displays the Video Display dialog box.

Palette   

Lets you select one of a few predefined palettes to apply to a grayscale live video. The palettes represent choices that may be useful in viewing different kinds of video in pseudo-colors. Choose among the following palettes:

Gray

Applies the standard 256-level grayscale palette to the Video window. This is a regular mode of viewing a grayscale video.

Inverse

Applies the inverted 256-level grayscale palette. The video will be displayed in the negative format.

Saturated

Applies the grayscale palette with colorized upper entries. The saturated palette allows you to control the dynamic range of the video signal by bringing it slightly below the saturation level of the video camera or video amplifier. To achieve the maximum dynamic range, adjust the intensity of the light source and/or the gain and zero level of the video amplifier so that the red color corresponding to the brightest pixel values just barely shows up.

Rainbow

Applies a color palette where the entries are evenly distributed along the Hue axis. This allows for assigning different color pigments to different levels of intensity.

Spectra

Applies a color palette where the entries are distributed along the Hue and Luminance axes. That allows for assigning different color pigments to different levels of intensity while preserving the luminance scale.

Isodense

Applies the 256-level grayscale palette, each 8-th entry of which is colorized. The isodense palette allows you to clearly see transitions between different levels of intensities as isolines on a topographic map.

Multiphase

Applies the multiphase palette. Entries in the multiphase palette are at opposite ends of the color model so even small changes in gray levels are highlighted.

Random

Applies the random color palette whose entries are filled with random values each time you select it from the menu.

Best Fit   

Automatically optimizes the palette or display range of the live video to provide the maximum contrast between the brightest and darkest pixels.