From 22c86364c7006ee80e2f9db1bcca82697b14ab42 Mon Sep 17 00:00:00 2001
From: Edgar O Silva <oswaldo.silva@gmail.com>
Date: Wed, 8 Jan 2014 14:33:03 -0600
Subject: [PATCH] Added example for video feed applying gaussianBlur and canny
 edges filter to the video frame feed. Updated typo in camera example.

---
 .../coffeescript/camera-gausian-effect.coffee | 58 +++++++++++++++++++
 examples/coffeescript/camera.coffee           |  2 +-
 2 files changed, 59 insertions(+), 1 deletion(-)
 create mode 100644 examples/coffeescript/camera-gausian-effect.coffee

diff --git a/examples/coffeescript/camera-gausian-effect.coffee b/examples/coffeescript/camera-gausian-effect.coffee
new file mode 100644
index 0000000..a6cfc32
--- /dev/null
+++ b/examples/coffeescript/camera-gausian-effect.coffee
@@ -0,0 +1,58 @@
+cv = require 'opencv'
+
+# First we create a new VideoCapture object to get
+# video from the camera (0 for default camera)
+camera = new cv.VideoCapture(1)
+
+# we create a window to display the Video frames
+namedWindow = new cv.NamedWindow('Video',1)
+
+# We set an interval to retrieve frames from the
+# video source and we get the intervalId so we can
+# stop the program from the video feed window.
+intervalId = setInterval(()->
+
+  # camera.read allows us to retriebe the current
+  # frame to be displayed in the video window.
+  camera.read((err, im) ->
+    # We can check for errors and even break the
+    # program execution if an error is detected here.
+    console.lof "The err ==>#{ err }" if err
+
+    # There is no need to display the image width or Height
+    # but I leave this here in case anyone needs to check them.
+    #console.log("Width: #{im.width()}")
+    #console.log("height: #{im.height()}")
+
+    # Before working with the frame we need to check the image
+    # is already available and has a width and height greater than 0,
+    # otherwise it will fail when trying to do namedWindow.show()
+    # and the image has width or height equal or less than 0.
+    if im.width() > 0 and im.height() > 0
+      # We apply filters and effects to the frame we got from the
+      # camera to manipulate the video that we'll display.
+      # First we convert to grayscale.
+      im.convertGrayscale()
+      # We then apply GaussianBlur.
+      # It takes an array of type double and size 2
+      # that indicates how strong the gaussian blur should be.
+      im.gaussianBlur([7,7])
+      # We then apply canny edge filtering.
+      # Params are lower and higher threshold and aperture size,
+      # although nodejs-opencv overwrite the aperture size param
+      # with 0. An update to consider it is needed.
+      im.canny(0, 30, 3)
+
+      # We use the previously created namedWindow to display the
+      # video frame to wich we applied the blur and filter.
+      namedWindow.show(im)
+
+    # Finally we get the key pressed on the window to terminate
+    # execution of the program.
+    res = namedWindow.blockingWaitKey(0, 20)
+    console.log("KEYPRESSED => #{ res } ")
+
+    # In this case I terminate the program if any key is pressed.
+    if res >= 0 then clearInterval(intervalId)
+  )
+, 50)
diff --git a/examples/coffeescript/camera.coffee b/examples/coffeescript/camera.coffee
index ec5a4e3..f5208c3 100644
--- a/examples/coffeescript/camera.coffee
+++ b/examples/coffeescript/camera.coffee
@@ -26,7 +26,7 @@ intervalId = setInterval(()->
 
     # We use the previously created namedWindow to display the
     # video feed frame, we need to check the image is already
-    # available and has a width and height greated than 0,
+    # available and has a width and height greater than 0,
     # otherwise namedWindow.show() will fail if any of those is 0.
     namedWindow.show(im) if im.width() > 0 and im.height() > 0