The OpenVX Specification  dba1aa3
Vision Functions

## Detailed Description

These are the base vision functions supported in OpenVX 1.1.

These functions were chosen as a subset of a larger pool of possible functions that fall under the following criteria:

• Applicable to Acceleration Hardware
• Very Common Usage
• Encumbrance Free

## Modules

Absolute Difference
Computes the absolute difference between two images. The output image dimensions should be the same as the dimensions of the input images.

Accumulate
Accumulates an input image into output image. The accumulation image dimensions should be the same as the dimensions of the input image.

Accumulate Squared
Accumulates a squared value from an input image to an output image. The accumulation image dimensions should be the same as the dimensions of the input image.

Data Object Copy
Copy a data object to another.

Accumulate Weighted
Accumulates a weighted value from an input image to an output image. The accumulation image dimensions should be the same as the dimensions of the input image.

Performs addition between two images. The output image dimensions should be the same as the dimensions of the input images.

Arithmetic Subtraction
Performs subtraction between two images. The output image dimensions should be the same as the dimensions of the input images.

Bitwise AND
Performs a bitwise AND operation between two VX_DF_IMAGE_U8 images. The output image dimensions should be the same as the dimensions of the input images.

Bitwise EXCLUSIVE OR
Performs a bitwise EXCLUSIVE OR (XOR) operation between two VX_DF_IMAGE_U8 images. The output image dimensions should be the same as the dimensions of the input images.

Bitwise INCLUSIVE OR
Performs a bitwise INCLUSIVE OR operation between two VX_DF_IMAGE_U8 images. The output image dimensions should be the same as the dimensions of the input images.

Bitwise NOT
Performs a bitwise NOT operation on a VX_DF_IMAGE_U8 input image. The output image dimensions should be the same as the dimensions of the input image.

Box Filter
Computes a Box filter over a window of the input image. The output image dimensions should be the same as the dimensions of the input image.

Non-Maxima Suppression
Find local maxima in an image, or otherwise suppress pixels that are not local maxima.

Canny Edge Detector
Provides a Canny edge detector kernel. The output image dimensions should be the same as the dimensions of the input image.

Channel Combine
Implements the Channel Combine Kernel.

Channel Extract
Implements the Channel Extraction Kernel.

Color Convert
Implements the Color Conversion Kernel. The output image dimensions should be the same as the dimensions of the input image.

Convert Bit depth
Converts image bit depth. The output image dimensions should be the same as the dimensions of the input image.

Custom Convolution
Convolves the input with the client supplied convolution matrix. The output image dimensions should be the same as the dimensions of the input image.

Dilate Image
Implements Dilation, which grows the white space in a VX_DF_IMAGE_U8 Boolean image. The output image dimensions should be the same as the dimensions of the input image.

Equalize Histogram
Equalizes the histogram of a grayscale image. The output image dimensions should be the same as the dimensions of the input image.

Erode Image
Implements Erosion, which shrinks the white space in a VX_DF_IMAGE_U8 Boolean image. The output image dimensions should be the same as the dimensions of the input image.

Fast Corners
Computes the corners in an image using a method based upon FAST9 algorithm suggested in [3] and with some updates from [4] with modifications described below.

Gaussian Filter
Computes a Gaussian filter over a window of the input image. The output image dimensions should be the same as the dimensions of the input image.

Non Linear Filter
Computes a non-linear filter over a window of the input image. The output image dimensions should be the same as the dimensions of the input image.

Harris Corners
Computes the Harris Corners of an image.

Histogram
Generates a distribution from an image.

Gaussian Image Pyramid
Computes a Gaussian Image Pyramid from an input image.

Laplacian Image Pyramid
Computes a Laplacian Image Pyramid from an input image.

Reconstruction from a Laplacian Image Pyramid
Reconstructs the original image from a Laplacian Image Pyramid.

Integral Image
Computes the integral image of the input. The output image dimensions should be the same as the dimensions of the input image.

Magnitude
Implements the Gradient Magnitude Computation Kernel. The output image dimensions should be the same as the dimensions of the input images.

Mean and Standard Deviation
Computes the mean pixel value and the standard deviation of the pixels in the input image (which has a dimension width and height).

Median Filter
Computes a median pixel value over a window of the input image. The output image dimensions should be the same as the dimensions of the input image.

Min, Max Location
Finds the minimum and maximum values in an image and a location for each.

Min
Implements a pixel-wise minimum kernel. The output image dimensions should be the same as the dimensions of the input image.

Max
Implements a pixel-wise maximum kernel. The output image dimensions should be the same as the dimensions of the input image.

Optical Flow Pyramid (LK)
Computes the optical flow using the Lucas-Kanade method between two pyramid images.

Phase
Implements the Gradient Phase Computation Kernel. The output image dimensions should be the same as the dimensions of the input images.

Pixel-wise Multiplication
Performs element-wise multiplication between two images and a scalar value. The output image dimensions should be the same as the dimensions of the input images.

Remap
Maps output pixels in an image from input pixels in an image.

Scale Image
Implements the Image Resizing Kernel.

Sobel 3x3
Implements the Sobel Image Filter Kernel. The output images dimensions should be the same as the dimensions of the input image.

TableLookup
Implements the Table Lookup Image Kernel. The output image dimensions should be the same as the dimensions of the input image.

Thresholding
Thresholds an input image and produces an output Boolean image. The output image dimensions should be the same as the dimensions of the input image.

Warp Affine
Performs an affine transform on an image.

Warp Perspective
Performs a perspective transform on an image.

Bilateral Filter
The function applies bilateral filtering to the input tensor.

MatchTemplate
Compares an image template against overlapped image regions.

LBP
Extracts LBP image from an input image. The output image dimensions should be the same as the dimensions of the input image.

HOG
Extracts Histogram of Oriented Gradients features from the input grayscale image.

HoughLinesP
Finds the Probabilistic Hough Lines detected in the input binary image.

Tensor Multiply
Performs element wise multiplications on element values in the input tensor data with a scale.

Performs arithmetic addition on element values in the input tensor data.

Tensor Subtract
Performs arithmetic subtraction on element values in the input tensor data.

Tensor TableLookUp
Performs LUT on element values in the input tensor data.

Tensor Transpose
Performs transpose on the input tensor.

Tensor Convert Bit-Depth
Creates a bit-depth conversion node.

Tensor Matrix Multiply
Creates a generalized matrix multiplication node.