Altami Software - software for image analysis
Altami Software
Software for image analysis

Threshold of color image filter


Used instruments: filter Threshold for colored images.

Objects of examination: photo with the volvox image by 4-times increase (Volvox.jpg).

Task: to select the background at the image.

NOTE. Tutorial does not contain the information on all the possibilities of the application. Here the optimal way of solving the task set is offered.

Step 1. Launch of the application

Launch the Altami Studio application. In order to launch the application, use the Altami Studio shortcut at the workbench or the menu item Start→Programs→Altami Ltd→Altami Studio 3.0. Besides, the application can be launched from the folder where the application was installed (usually it is C:\Program Files\Altami Ltd\Altami Studio 3.0\).

Step 2. Opening the file

In Altami Studio application open the file with the image, in order to do that use the menu item File→Open and mark the Volvox.jpg. It is in Tutorials\Pictures folder which is in the main folder of the application. Click the Open button.

The following image shall appear in the application window:

Picture 1. Opened document in Altami Studio application.

Step 3. Adding the Threshold of color image filter to the document

In order to use the Threshold of color image filter, call the Filters panel through the Filters→Filters menu.

Image 2. Opening the Filters panel

Then at the appeared Filters panel click with the right button of the mouse and at the context menu select FiltersColor transformationsThreshold of color image.

Image 3. Adding the Threshold of color image filter

Step 4. Adjustment of the Threshold of color image filter

Select the name of the «Threshold of color image» filter and there will appear the window with settings of this filter in its lower part.

Image 4. Filter Threshold of color image

Turn off the filter having put away the tick near the enabled parameter.

Image 5. Settings panel of the Threshold of color image filter

Leave the threshOperation parameter with the value by default (ThreshBinary).

Also, leave the value of radius parameter as 10 by default. ThreshValue parameter defines the base color which be searched in the image. Direct the cursor to the background field (yellow color) as it is shown in the Image 6. In the Status bar such color values as r (red), g (green) и b (blue).

Image 6. Defining the color of the image background

Image 7. Value of color parameters

Select the ThreshValue having clicked on its value as it is shown at the Image 5. Click the appeared by that button ….

Image 8. The panel of color choice for Threshold value parameter

In the appeared Select color window indicate r, g и b parameters of the cursor, previously found and shown at the Image 7.

Image 9. Search of the image background color

Add the selected by you color to the user colors panel having clicked the button Add to Custom Colors, in order that not to look for that color again. Click ОК button. Turn on «Threshold of color image» filter, having put the tick in front of the enabled parameter.

Image10. Action of the Threshold of color image filter by Binarization operation

Select in the thresholdType parameter Hue value.Method of the nearest color search will be working according to the tone parameter in HSV tone.

Image 11. Action of the Threshold of color image filter by Hue type of transformation

Select in the threshOperation parameter ThreshBinaryInv value (image 12).

Image 12. Action of the Threshold of color image filter by ThreshBinaryInv operation

Correct the value of the radius parameter as 12. So, the background is separated from the objects in the image.

Image 13. The result of the Threshold of color image transformation

Read more on the subject:

Sub background filter
Pseudocolor filter
Sobel filter
Laplace filter
Threshold filter
Adjust histogram
Configured find contours
Inpaint image by mask filter
Inpaint black pixels in image filter
Adaptive threshold filter


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