AI.CV.ImageProcessors

ImageProcessors is a functional (Processor-based) interface to computer vision using OpenCV.

The Processor interface allows the primitives in this library to take care of all the allocation / deallocation of resources and other setup/teardown requirements, and to appropriately nest them when combining primitives.

Simple example:

 win = window 0        -- The number is essentially a label for the window
 cam = camera 0        -- Autodetect camera
 edge = canny 30 190 3 -- Edge detecting processor using canny operator

 test = win . edge . cam   -- A processor that captures frames from camera and displays edge-detected version in the window.

Documentation

type ImageSink = Processor IO (Ptr IplImage) ()

type ImageSource = Processor IO () (Ptr IplImage)

type ImageProcessor = Processor IO (Ptr IplImage) (Ptr IplImage)

keyPressed :: Show a => a -> IO Bool

Some general utility functions for use with Processors and OpenCV

Predicate for pressed keys

runTill :: Monad m => Processor m () b -> (b -> m Bool) -> m b

Runs the processor until a predicate is true, for predicates, and processors that take () as input (such as chains that start with a camera).

runTillKeyPressed :: Show a => Processor IO () a -> IO ()

Name (and type) says it all.

camera :: Int -> ImageSource

A capture device, using OpenCV's HighGui lib's cvCreateCameraCapture should work with most webcames. See OpenCV's docs for information. This processor outputs the latest image from the camera at each invocation.

window :: Int -> ImageSink

A window that displays images. Note: windows with the same index will be the same window....is this ok?

imageProcessor :: (Ptr IplImage -> Ptr IplImage -> IO (Ptr IplImage)) -> (Ptr IplImage -> IO (Ptr IplImage)) -> ImageProcessor

A convenience function for constructing a common type of processors that work exclusively on images

resize :: Int -> Int -> InterpolationMethod -> ImageProcessor

OpenCV's cvResize

dilate :: Int -> ImageProcessor

OpenCV's cvDilate

canny

Arguments

:: Int

Threshold 1

-> Int

Threshold 2

-> Int

Size

-> ImageProcessor

OpenCV's cvCanny

haarDetect

Arguments

:: String

Cascade filename (OpenCV comes with several, including ones for face detection)

-> Double

scale factor

-> Int

min neighbors

-> HaarDetectFlag

flags

-> CvSize

min size

-> Processor IO (Ptr IplImage) [CvRect]

Wrapper for OpenCV's cvHaarDetectObjects and the surrounding required things (mem storage, cascade loading, etc).

drawRects :: Processor IO (Ptr IplImage, [CvRect]) (Ptr IplImage)

OpenCV's cvRectangle, currently without width, color or line type control