CS320n –Visual Programming Image Manipulation

What We Will Do Today Look at how to alter images using LabVIEW Visual Programming Image Manipulation

Loading Images VI Block Diagram of VI that allows user to load jpg images from a file and displays the image Visual Programming Image Manipulation

Image Data The image cluster contains a lot of data The heart of the image is an array of ints each int only uses 1 byte or 8 bits represents a number from 0 – 255 three ints in a row represent the red, green, and blue intensity for 1 pixel elements 0, 1, 2 are for the pixel at row 0, column 0, the upper left corner Visual Programming Image Manipulation

Image Data Visual Programming Image Manipulation

Image Data Visual Programming Image Manipulation

RGB Colors What color is that pixel at the top left corner? Looks very black Unbundle image to get at image array Visual Programming Image Manipulation

RGB Colors First three elements of image array are 27, 26, and 5 Intensity of red from 0 to 255 0 is none, 255 is maximum a little red, a little green, almost no blue very close to black, all three 0 Visual Programming Image Manipulation

Viewing a Single Color Developed a VI to do this in an early lab a single function exists Controls and indicator added. Visual Programming Image Manipulation

Sample Single Colors Black. Moss? Visual Programming Image Manipulation

How Many Colors If the encoding of an image allows red, green, and intensity values of 0 – 255 there are 256 * 256 * 256 = 16,777,216 possible colors 1 byte per color per pixel 3 bytes total per pixel, 24 bits a.k.a. 24 bit image Visual Programming Image Manipulation

Altering Images Some programming tools allow individual pixels or areas to be affected, recolored. We will look at altering image by affecting all pixels in the image need to work with the color data can work with the array of colors from image OR “unflatten” the image data to a 2d array go from an array of 1 dimension (like a list) to an array with 2 dimensions, like a table Visual Programming Image Manipulation

Unflatten Image Function Most interested in the 24-bit pixmap Visual Programming Image Manipulation

Unflattening the Image Image Wire Displaying value in element 0,0 Shown as a hexadecimal number, base 16. 1B = red component, 1 * 16 + 11 * 1 = 27 1A = green component, 1 * 16 + 10 * 1 = 26 05 = blue component, 0 * 16 + 5 * 1 = 5 Visual Programming Image Manipulation

One filter – Invert image Invert the image set each pixel = 16,777,215 – original value auto indexing really shines 2d array single element 1d array flatten back to image Visual Programming Image Manipulation

Original Visual Programming Image Manipulation

Result Visual Programming Image Manipulation