The blob locator tool converts the input grayscale image into a binarized black-and-white image before performing image processing. The user must choose how many thresholds are used (one or two) and how the thresholds are determined (Auto or Fixed).
The left dropdown box defines how the threshold is set. Select one of the following:
The Fixed method requires the user to set the threshold manually. All subsequent images will use this threshold value to change the grayscale values to black (with a grayscale value of zero), or white (with a grayscale value of 255), depending on whether they are less than, or greater than, the threshold value.
The Auto method uses the threshold value set by the user and the average grayscale value of the image. When the average grayscale value changes after an image is acquired, the threshold value changes to compensate for the average brightness of the image.
The right dropdown box determines how many thresholds values are used. Select one of the following:
Single indicates that there is one threshold value. Grayscale values less than the threshold are set to black (with a grayscale value of zero). Grayscale values greater than the threshold are set to white (with a grayscale value of 255). When the Single method is set, the user must edit the Threshold value. The Lower Threshold value and Upper Threshold value will not be visible.
Dual indicates that there are two threshold values, an upper and a lower threshold. Grayscale values that are between the thresholds are set white (with a grayscale value of 255). Grayscale values outside of the threshold limits are set to black (with a grayscale value of zero). When the Dual method is set, the user must edit the Lower Threshold value and the Upper Threshold value. The Threshold value will not be visible.