Operator ColSum

This operator calculates the sum of all pixel values for each image column. Each pixel value at the output represents the current sum of the respective column. Thus, each pixel is replaced by the sum determined so far.

It is possible to clear the current column sum manually by setting the ClrI link to 1. When a manual clear is not required, a constant 0 must be applied to ClrI.

With every new input frame, the sum for all columns is set to zero.

Often, this operator is used in conjunction with operator RemoveLine to use only the last image line containing the results for the full frame.

The following example shows the relation of input values to output values:

Image Restrictions:

  • Image Size

    All lines of an input image must have the same length. Images with varying line lengths are not allowed.

  • Empty Images

    Empty Images, i.e,. images with no pixels, are allowed. The operator will output an empty image.

  • Image Protocols

    Only VALT_IMAGE2D and VALT_LINE1D image protocols are supported.

I/O Properties

Property Value
Operator Type O
Input Links I, Image Input
ClrI, Clear Input
Output Link O, Data Output

Supported Link Format

Link Parameter Input Link I Input Link ClrI Output Link O
Bit Width [1, 64] unsigned, [2, 64] signed 1 auto/manual12
Arithmetic {unsigned, signed} unsigned as I
Parallelism any as I as I
Kernel Columns 1 as I as I
Kernel Rows 1 as I as I
Img Protocol {VALT_IMAGE2D, VALT_LINE1D} as I as I
Color Format VAF_GRAY as I as I
Color Flavor FL_NONE as I as I
Max. Img Width any as I as I
Max. Img Height any as I as I

1

For the image protocol VALT_IMAGE2D, the output bit width is automatically calculated from the input bit width and the maximum image height. The output bit width is determined by

The output bit width must not exceed 64 Bit.

2

For the image protocol VALT_LINE1D, the output bit width must be set manually on the output link.

The output bit width must be greater than 2 and must not exceed 64 bit.

Parameters

None

Examples of Use

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

  • 'Laser Triangulation'

    Examples - A high speed and robust laser line detection algorithm. The algorithm determines center of gravity coordinates to obtain sub-pixel resolution results.

  • 'ImageSplitAndMerge'

    Examples - Shows how to split an merge image streams. Appends a trailer to the image.