Basic Tools In Image Processing

The image above shows some of the basic tools of the program NIH Image. The following are brief descriptions of the tools and how they are used. Their skillful use will allow you to accomplish some very sophisticated image processing techniques and analysis.

Look Up Table: Displays color or shades of gray which are assigned to each pixel. There are 256 gray scale colors (255=absolute black, 0=absolute white).

Magnifying Glass: Magnifies the image up to 64x. Option Click will de-magnify the image.

Hand: Moves the image around the screen.

Pencil: Freehand draws one pixel on the image.

Eraser: Erases the foreground image.

Paint Brush: Paints on the image.

Line Width: Draws straight lines. Double Clicking the line, changes line width.

Paint Bucket: Fills all pixels within a confined area with the same color.

Density Profile Tool: Produces density profile plots

Magic Wand: Selects outlines.

Angle Measuring Tool: Selects and measures angles.

Reserved Colors: Six colors can be set aside (reserved). These reserved colors can be used to draw on the images.

Contrast/Brightness: Drag handles or sliders to change brightness or contrast of the image.

Rectangular Drawing Tool: Produces rectangular selections. Press the shift key to make squares.

Elliptical Drawing Tool: Produces elliptical selections. Press the shift key to make circles.

Polygon Drawing Tool: Produces polygon selections.

Freehand Drawing Tool: Produces freehand selections.

Line Selection Tool: Produces line selections.

Density Slicing Tool: Manipulates the LUT and highlights pixels of specific values.

Text Tool: Prints text on images.

Spray Paint Can: Sprays paint unto the image.

Eye Dropper Tool: Picks up colors from the image or Look Up Table.

Coordinate Tool: Marks and measures coordinates.

Line Width: Sets line width for coordinate tool, line tool, and profile plot tool.

Info Box: Shows the following type of information: cursor coordinates (x,y), pixel value, count, pixels. mean, Std Dev, Min. Max, length. The contents of this window change due to different actions being accomplished.

Turning on balloon help and moving the cursor over the different tools, will provide additional information concerning the tool in question.

Practice using these tools on the provided images to gain familiarity with their use.

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