Microscan Quadrus EZ, User Manual, Page: 214 / 366

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Quadrus EZ Reader User’s Manual
Evaluation
Histogram
Note: Since histograms are performed in the reader, the results will be save regardless of
whether the image was captured as a BMP or JPG.
1. From the Evaluation window, click the Histogram button.
The current image is transferred into the histogram operation. This may take a
moment since all relevant pixels are being evaluated intensively.
2. When the Histogram window opens, you might need to expand the window and/or
adjust the scroll bars in order to bring the image into view.
3. To generate a histogram, click and drag your mouse pointer diagonally across the
symbol or a portion of it.
Threshold (Histogram)
Enable Autothreshold is checked by default.
To manually adjust the threshold,
1. Uncheck the Enable Autothreshold checkbox.
2. Move the threshold marker (vertical green dashed line) in the Histogram chart.
Hint: This should be midway between the maximum and minimum curves.
3. Click on the Send Threshold button to adopt the new threshold position.
Histogram Evaluation
In a histogram, the first peak from the left is the Low Peak. Its highest point occurs at 20 in
the dark-to-light range. The next peak is the High Peak which occurs at 141.
The minimum (dark) and maximum (light) represent the entire range of pixels that are
derived from the capture.
Threshold is the mean setting and represented by a vertical dashed green line. In practical
terms, the threshold represents the point at which all pixels on the left are regarded as
dark and all to the right as light.
You can adjust the threshold by unchecking the Enable Autothreshold checkbox, moving
the threshold and clicking Send Threshold to save the new setting.
Usage: Useful in determining quality and contrast of symbols.
Definition:
A histogram is a graphical presentation of the numeric count of the occurrence
of each intensity (gray level) in an image. The horizontal axis is the values
of gray levels and the vertical axis is the number of pixels for each gray
level.