Trevista Edit Control

Cognex VisionPro 9.25 SR1

The Trevista tool edit control provides a graphical user interface to the CogTrevistaTool, which accepts an interlaced image from a Trevista CI Dome and uses computational imaging to generate output images to highlight features that raw camera images cannot display. The following figure shows an input image from a Trevista Dome Light and the depth image it generates to highlight surface defects:

See the topic Using a Trevista Tool for an introduction to using a Trevista CI Module. The following figure shows the Trevista tool edit control available in QuickBuild:

See the following sections for more information:

Settings Tab
Advanced Tab
Graphics Tab
Control Buttons

Settings Tab

Use the Settings tab to determine which output images you want to generate and set various output image parameters:

The Settings tab offers the following controls:

Control	Description
Tool Result Images	Enabling the checkbox for a given type of image enables the production of the named result image, while selecting the row displays the properties specific to that image. See the topic Using a Trevista Tool for descriptions.
Output Bit Depth	For the selected image (for example, Greyscale or Depth), you can choose to generate an output image of type CogImage8Grey or CogImage16Grey to continue processing the image. See the topic Vision Tools and Supported Image Types for a list of the supported image types for all the vision tools or operators in this release.
Floating Point to Grey Mapping	A Trevista tool uses a computational imaging algorithm to produce a set of pixel values initially stored as floating point numbers. The tool then maps these floating point numbers to greyscale pixel values in the output image. The edit control offers a histogram representing the floating point values and controls for mapping the BlackLevel and WhiteLevel in the specific output image selected under Tool Results Images. The tool maps the floating point value of Map to Black to black - the integer output value zero. The tool maps the floating point value of Map to White to the maximum pixel value for the specified type of output image: 255 for CogImage8Grey 65535 for CogImage16Grey The tool linearly maps any floating point value that falls between these two limits to an intermediate shade of grey, with floating point numbers closer to Map to Black receiving darker pixel values and floating point values closer to Map to White receiving lighter pixel values. The tool maps floating point values outside the range of Map to Black and Map to White as either black or white, depending on which limit is closer. Experiment with these parameters to get the best results for your vision application.
Depth Mode	For Depth images only, use Local mode to compute the relative heights of surface areas that lie near each other in your image, or Global mode to compute the relative heights of surface areas that lie far away from each other in your image. Cognex recommends Global mode for surfaces that have large, flat areas that are not perpendicular to the optical axis of your lens. Be aware that Local mode requires an interative procedure and processing time will increase.
Depth Level	Specify a depth-calculation level for Depth images: For a Depth Mode of Global, set the depth level to a number that is approximately the size (in pixels) of the entire surface over which you wish to compute the depth. For a Depth Mode of Local, set the depth level to a number that is bigger than the size (in pixels) of the local surface patch over which you wish to compute the depth.

Advanced Tab

Use the Advanced tab to set less-common parameters:

The Advanced tab offers the following controls:

Control

Description

Sensor Correction Parameters

Check Enabled to use specific parameters for the calculation of the Shape Horizontal and Shape Vertical images.

Dome Diameter (mm): Specify the diameter of the dome illumination unit in millimeters.
- Small Trevista Dome: 120 mm
- Medium Trevista Dome: 300 mm
- Large Trevista Dome: 580 mm
Pixel Size (mm): Specify the distance in millimeters that corresponds to the width or height of one pixel in the input image.
Modifier: Specify a value between -1 to 1 to apply to account for distortion from reflectance, sensor position, or other factors.

Processing Parameters

Specify additional processing parameters:

CPU / GPU if Available: Choose the preferred mechanism for processing results.
Max Thread Count: Set the maximum number of threads to use when processing with a CPU.
GPU Device Index: Sets the target GPU when the PC supports more than one.

Graphics Tab

Use the Graphics tab to choose which image records the tool makes available in the local and floating image displays:

Check each type of output image you want to make available in the edit control display. Be aware the tool will not generate an image record for any given output image type if you do not also select it on the Settings tab. For example, if you enable Shape Vertical on the Graphics tab but do not select Shape Vertical in Tool Result Images on the Settings tab, there will not be a record for LastRun.OutputShapeVerticalImage in the display.

In addition, use Show Input Image to determine whether or not the input image is recorded as part of the diagnostic record, and whether the image is copied to the record or saved in the record as a reference.

Control Buttons

The following table describes the function of each button:

Button	Description	Function
	Run	Take the input CogImage8Interlaced and unpack its 8-bit pixels into four "shading" images, then process those images to produce the requested output images.
	Electric mode	Toggle electric mode, where the Trevista tool executes automatically when particular configuration parameters change. In electric mode, a lightning bolt appears next to every electric property.
	Local image display	Open or close the local image display window. A Trevista tool supports the following image buffers: The Current.InputImage contains the latest acquired image. The LastRun.InputImage contains last image the tool processed. The LastRun.OutputGreyscaleImage contains the greyscale image the tool generates. The LastRun.OutputDepthImage contains the depth image the tool generates. The LastRun.OutputContourImage contains the contour image the tool generates. The LastRun.OutputShapeHorizontalImage contains the image lit by the Trevista Dome Light to highlight vertical features. The LastRun.OutputShapeVerticalImage contains the image lit by the Trevista Dome Light to highlight horizontal features. The LastRun.ShadingImage"X" contains the image lit by one of four quadrants inside the Trevista Dome Light.
	Floating image display	Open a floating image window, which supports the same image buffers as the local image display window.
	Open	Open a VisionPro persistence (.vpp) file that contains a set of saved properties for this vision tool object type. VisionPro reports an error if you try to open a .vpp file for another object type.
	Save	Save the current properties of the vision tool to a VisionPro persistence (.vpp) file. The edit control allows you to choose between saving the vision tool with or without its image buffers and tool results.
	Save As	Save the current properties of the vision tool to a new VisionPro persistence (.vpp) file.
	Reset	Reset the vision tool to its default state. The tool gives you a choice between resetting to the default-constructed state, which is appropriate when you are using it in a Visual Studio.NET application, and its template-initialized state, which is appropriate for QuickBuild applications.
	Show ToolTips	Enable or disable the display of tooltips for individual items in the edit control.
	Help	Open this VisionPro online help file.