Retina is a brand name trademarked by apple and refers to a display with a pixel density such that the individual pixels are discernible to the human eye. DPI is also used when referring to the computer mouse sensitivity and how far the mouse cursor will move on the screen for a given distance of actual movement. While pixels per inch is a measure of screen density in pixels, dots per inch is a measure of the density in dots.ĭots, sometimes also called points when referring to a screen, might encompass multiple pixels or might be smaller than a pixel depending on the resolution and pixel size.ĭPI is most often used when measuring the resolution of a printer, which prints in dots rather than 1:1 to the pixels of the screen. Thus, screen pixel density in pixels per inch is equal to the pixels along the diagonal d p divided by the diagonal in inches d i.ĭots per inch, or DPI, are very similar to pixels per inch, but they are slightly different. Given the diagonal measurement in pixels and inches, use the following formula to calculate PPI. For instance, the width in pixels of a 1920×1080 screen is 1920, and the height is 1080. The width in pixels is equal to the first part of the screen’s resolution, and the height is the second.
In other words, the diagonal pixels d p is equal to the square root of the width in pixels w squared plus the height in pixels h squared. Given the screen’s resolution, you can find the number of pixels along the diagonal using the Pythagorean theorem. This might seem complicated, but you can use the Pythagorean theorem to find this using the screen’s resolution.
The second step to calculating PPI is finding the total number of pixels along the diagonal measurement. Or, simply use our screen size calculator to find the size. If not, measure the diagonal from one corner to the opposite corner using a tape measure. Most displays, screens, monitors, and televisions are sold by their diagonal measurement, which should be marked on the screen or its documentation. The first step to calculate PPI is to measure the screen’s diagonal size in inches.
verification of an alarm from the security alarm system.Detection is the selection of a control object from the background or the separate perception of two control objects located at a distance from each other, commensurate with their sizes: Here are some typical operator’s task for video surveillance systems: Calculation of pixel density is required to select a security camera for such tasks as personal identification, recognition, observation, detection, and monitoring.Ĭriteria for solving video surveillance tasks
Pixel Density is the ratio of the horizontal camera resolution in pixels to the width of the field of vision in meters or feet.
Pixel Density Calculator is a free online tool for CCTV design.