Binarized Color Thresholding Filter Tool

Binarized Color Thresholding Filter Tool

This tool allows the user to set thresholds for the RGB or HSI image channels. The user selects to which color representation the thresholding will be applied (RGB or HSI). The user then selects the lower and upper pixel range (Range 0-255) for each image channel. These ranges determine the binarized image, i.e. outside the range: 0 inside the range: 255 (for an 8-bit image). The three planes are then AND'd together to produce the output image from the tool. There is also an option to invert the output result for use in masking operations.

Note that the HSI plane selection available is further refined to allow the user to select a hue value of zero to represent either pure red, pure green or pure blue. This is necessary in order to avoid wrap around issues. For instance, when looking at reddish hues with a hue value of zero representing pure red, a color slightly towards green has a low hue value whereas a color slightly towards blue has a value close to 255. Choosing to use hue 0 = green or blue for this case would eliminate this problem for the two reds above.

FIGURE 13-15.

Hue Wheel

Figure 13-16 shows the Color Thresholding Filter Step being inserted into the inspection. Note that this step should only be available when the snapshot buffer is a color image.

FIGURE 13-16. Insertion

of Color Thresholding Filter

Figure 13-17 displays the options available for Color Thresholding in RGB space.

FIGURE 13-17. Options for Color Thresholding Filter

Figure 13-18 displays the selection of the different color space models available. They are RGB, HSI (Hue Red =0). HSI (Hue Green =0), HSI (Hue Blue =0).

FIGURE 13-18. Options for RGB Color Space Thresholding

Figure 13-19 displays the parameters available when the color space HSI (Hue Green =0) is selected.

FIGURE 13-19. Options for HUE Color Space Thresholding

Figure 13-20 displays the output of the Color Thresholding Filter Color Space RGB threshold range 0-128 for all planes.

FIGURE 13-20. Results of Color Thresholding RGB Space 0-128