Pixel density tells you how many million pixels fit or would fit in one square cm of the sensor. Olympus VH-510 has a pixel density of 42.06 MP/cm².
These numbers are important in terms of assessing the overall quality of a digital camera. Generally, the bigger (and newer) the sensor, pixel pitch and photosite area, and the smaller the pixel density, the better the camera. If you want to see how VH-510 compares to other cameras,