Operator ExpandLine

The operator ExpandLine stores the last image line of each input image. This stored image line will used to replace all image lines of the next image at the output. In other words, the operator copies the last image line to all lines of the next image.

Mind, that the behavior of this operator will only affect the following frame and not the current frame. Therefore, the output data of the first frame after acquisition start has to be be specified using parameter Init.

If the width of a successive frame is less than the previous frame, the operator will keep the image dimension and only output the first part of the stored line. If the width of a successive frame is greater than the previous frame, the operator will fill the missing pixels with random memory content.

Operator Restrictions

  • Empty images are not supported.

    Images with varying line lengths are not supported.

    Input image dimension must be equal to the maximum image dimensions set in the link.

I/O Properties

Property Value
Operator Type O
Input Link I, data input
Output Link O, data output

Supported Link Format

Link Parameter Input Link I Output Link O
Bit Width [1, 64]1 as I
Arithmetic {unsigned, signed} as I
Parallelism any as I
Kernel Columns any as I
Kernel Rows any as I
Img Protocol VALT_IMAGE2D as I
Color Format any as I
Color Flavor any as I
Max. Img Width any as I
Max. Img Height any as I


The range of the input bit width is [1, 64] for unsigned inputs. For signed inputs, the range is [2, 64]. For unsigned color inputs, the range is [3, 63] and for signed color, the range is [6, 63].


Type static parameter
Default 0
Range [0, 2^InputBitWidth - 1]

The parameter specifies the initialization value of the pixels of the first output frame. The parameter will only accept unsigned values. For signed initialization values enter its unsigned representation.

Examples of Use

The use of operator ExpandLine is shown in the following examples: