First Bytes - LabVIEW

Today’s Session Introduction to LabVIEW Colors and computers Lab to create a color picker Lab to manipulate an image Visual ProgrammingImage Manipulation2

3 LabView LabVIEW is a graphical programming language –as opposed to a text based programming language such as Java or C++ –originally developed to collect and analyze data from instrumentation. –can be used as a general purpose programming language There are similarities –must think about what the problem is –what is the program suppose to do? –must plan a solution –must implement and test the solution The difference is what you do when implementing solution. –typing vs. working with icons

Colors and Computers Computers store numbers. How to store colors? Color models RGB Look at source code for a web page –search for “color” Visual ProgrammingImage Manipulation4

Visual ProgrammingImage Manipulation5 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

Exercise Complete LabVIEW program to create a color picker Visual ProgrammingImage Manipulation6

Visual ProgrammingImage Manipulation7 Loading Images VI Block Diagram of VI that allows user to load jpg images from a file and displays the image

Visual ProgrammingImage Manipulation8 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 ProgrammingImage Manipulation9 Image Data

Visual ProgrammingImage Manipulation10 Image Data

Visual ProgrammingImage Manipulation11 RGB Colors What color is that pixel at the top left corner? Looks very black Unbundle image to get at image array

Visual ProgrammingImage Manipulation12 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 ProgrammingImage Manipulation13 Viewing a Single Color Developed a VI to do this in an early lab a single function exists Controls and indicator added.

Visual ProgrammingImage Manipulation14 Sample Single Colors Moss? Black.

Visual ProgrammingImage Manipulation15 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 ProgrammingImage Manipulation16 Unflatten Image Function Most interested in the 24-bit pixmap

Visual ProgrammingImage Manipulation17 Unflattening the Image Image Wire Displaying value in element 0,0 Shown as a hexadecimal number, base 16. 1B = red component, 1 * * 1 = 27 1A = green component, 1 * * 1 = = blue component, 0 * * 1 = 5

Image Manipulation Program already done to pull out red, green, and blue components Now make changes such as –swapping –brighter –darker –remove one color channel –invert –posterize Visual ProgrammingImage Manipulation18

Visual ProgrammingImage Manipulation19 Original

Visual ProgrammingImage Manipulation20 Result