Highgui and ruby

opencv, ruby

Solution

Not sure which wrapper you are using, but you should take a look at this: Ruby/OpenCV - An OpenCV Ruby wrapper.

Face detection sample:

#!/usr/bin/env ruby

require 'opencv'

include OpenCV

# Load an image
img = IplImage.load('sample.jpg')

# Load the cascade for detecting faces
detector = CvHaarClassifierCascade::load('haarcascade_frontalface_alt.xml.gz')

# Detect faces and draw rectangles around them
detector.detect_objects(img) do |rect|
  img.rectangle!(rect.top_left, rect.bottom_right, color: CvColor::Red)
end

# Create a window and show the image
window = GUI::Window.new('Face Detection')
window.show(img)
GUI::wait_key

The classifier can be downloaded here.

EDIT:

The following code uses OpenCV, the rb_webcam gem, and RMagick to capture an image from a webcam and save it as a jpg file:

require 'rb_webcam'
require 'RMagick'

capture = Webcam.new

image = capture.grab
width = image.size[:width]
rows = image.data.unpack("C*").each_slice(3).to_a.each_slice(width).to_a
capture.close

height = rows.length
img = Magick::Image.new width, height

rows.each_with_index do |r, i|
q = r.map {|b, g, r| Magick::Pixel.new r * 256, g * 256, b * 256, 0}
img.store_pixels(0, i, width, 1, q)
end

img.format = 'jpg'
img.write 'webcam.jpg' 

Problem

Original source