AtomSpace Computer Vision Types

Atomese wrappers around a subset of OpenCV

The general idea is that theImageValues will hold a handle to the image being processed, and theImageBlurLink,and other things of that kind specify the kinds of transformations to be applied to the image. The actual images are never in the AtomSpace, only the abstract processing tree, and a way of hooking that tree to the image(s) to be processed.

Status

• It is possible to read an image from a file usingImageNode,its name corresponds to the image file location.
• There are a few OpenCV operations that you can invoke both on image Nodes and Values. They returnImageValues. Look down for usage info in Scheme.
• Saving images supported withImageWriteLink.

Building

Dependencies

• CMake (build dependency)
• OpenCV (libopencv-devpackage on Debian-derived Linux distributions)
• AtomSpace

Commands

The basic command is just CMake:

cmake -B build/ -S.

Thencmake --build buildandsudo cmake --install build

If you have VCPkg and / or you want to use something like clangd that requirescompile_commands.json,there is theconfigure.shscript that runs a slightly extended version of the above command (exportVCPKG_ROOTwith the path to your VCPkg).

Library Usage

CMake

• find_packagelibrary name:AtomSpaceVision.
• Target to link with:AtomSpace::Vision.

Types Usage

For Scheme users:

• (Image "<file-path>" )opens an image from a given file.
• (ImageBlur <Image or ValueOf> (Number <kernel size>))to setup acv::bluroperation.
• (ImageWrite <Image or ValueOf> <Concept or ValueOf>)writes an image to a given location.
• (ImageHalfSize <Image or ValueOf>)to setup acv::pyrDownoperation.
• (ImageFilter2D <Image or ValueOf> (Number <ddepth>) <Image or ValueOf>:kernel)to setup acv::filter2Doperation.

More plans and ideas

Other required and optionalImageFilterLinks. These are described athttps://docs.opencv.org/4.5.3/d4/d86/group__imgproc__filter.html

• display to screen for debugging. So,ImageDisplayLink.

• thresholding, convert to greyscale, convert to binary b/w.

• ImageRectangleLink- this needs to be a white rectangle on a black background, with a given width, height, postion. To be used with the above to select regions (butRectis a separate type in OpenCV that is used by other procedures for selecting ROI, is this necessary as a Link then?).

• HaarWaveletLink- we want to search for features in a position-independent, scale-independent way. We need a good API for that. Not at all clear what a good API for that might be... Really, we want something affine... Maybe this:http://wavelet2d.sourceforge.net/

• erode()... maybe useful later??

• Extract hue, saturation, value, extract red, green blue channels. How to do this in opencv??

• Maybe a circle or ellipse? to answer yes/no to circular feature questions.