Measurement Tools¶
Line Profile Tool and Measuring Distance¶
SanjVIEW's line profile tool can be used to convert pixel measurements in a captured image into physical distance units. This is done by calibrating the image's pixel-to-distance scale against a feature of known physical size, then applying that scale to line profiles drawn elsewhere in the image.
To determine the distance scale for an image:
- Identify a feature in the image with a known physical size — for example, a bond pad of a known dimension (such as 100 µm) or a feature on a calibration substrate (such as a 500 µm reference feature). [diagram/image in source — not reproduced here — the source shows an annotated screenshot, "Draw line on a known feature size, e.g. 100µm pad or calibration substrate."]
- Using the line profile tool, draw a line across the full width of the known feature. [diagram/image in source — not reproduced here — the source shows the line profile tool and its "Line info" readout overlaid on a screenshot labeled "Microsanj Test Sample."]
- Read the line's pixel length from the line info readout. Note that the total pixel count reported includes an initial zero-index pixel, so the number of pixel intervals spanned by the line is one less than the total pixel count reported.
- Calculate the distance-per-pixel scale factor by dividing the known feature size by the number of pixel intervals:
For example, in the source document's sample measurement, a line profile drawn across a 500 µm feature reported 428 total pixels. Subtracting 1 for the zero-index pixel gives 427 pixel intervals, so:
Once you have established the distance-per-pixel scale factor for an image, you can apply it to any other line profile drawn in that same image: multiply the pixel length reported by the line profile tool (minus 1, for the zero-index pixel) by the distance-per-pixel value to obtain the physical distance represented by that line.