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step

System object: visionhdl.MeasureTiming
Package: visionhdl

Measure timing of pixel control structure input

Syntax

[activePixels,activeLines,totalPixels,totalLines,horizBlank,vertBlank] = step(measure,ctrlIn)

Description

Note

Alternatively, instead of using the step method to perform the operation defined by the System object™, you can call the object with arguments, as if it were a function. For example, y = step(obj,x) and y = obj(x) perform equivalent operations.

[activePixels,activeLines,totalPixels,totalLines,horizBlank,vertBlank] = step(measure,ctrlIn) incorporates the current pixel location into calculations of video frame timing. The control signals, ctrlIn, associated with each pixel indicate the location of this pixel relative to the active frame boundaries. The input object measures the time steps between the control signals to determine the parameters of each frame.

Note

The System object performs an initialization the first time you call the step method. This initialization locks nontunable properties and input specifications, such as dimensions, complexity, and data type of the input data. If you change a nontunable property or an input specification, the object issues an error. To change nontunable properties or inputs, first call the release method to unlock the object.

Input Arguments

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Specify a visionhdl.MeasureTiming System object that you created and configured.

Control signals accompanying the input pixel stream, specified as a pixelcontrol structure containing five logical data type signals. The signals describe the validity of the pixel and its location in the frame. For more details, see Pixel Control Structure.

Data Types: struct

Output Arguments

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The diagram shows the output measurements, as determined from the pixel stream control signals.

For details on the pixel control bus and the dimensions of a video frame, see Streaming Pixel Interface.

Note

Measurements from the first simulated frame are incorrect because some parameters require measurements between frames. Simulate at least two frames before using the results.

This value is measured between hStart and hEnd. See marker 1 in the diagram.

This value is measured as the number of hStart pulses between vStart and vEnd. See marker 2 in the diagram.

This value is measured from hStart to the next hStart, including the horizontal blanking interval. See marker 3 in the diagram.

This value is measured by the interval from vEnd to the next vEnd, divided by totalPixels. It includes the vertical blanking interval. See marker 4 in the diagram.

The horizontal blanking interval is the number of inactive pixels between lines of a frame. This value is measured between hEnd and the next hStart. See marker 5 in the diagram.

The vertical blanking interval is the number of inactive lines between frames. This value is measured from vEnd to the next vStart, adjusted to remove horizBlank, then divided by totalPixels. See marker 6 in the diagram.

Introduced in R2016b