CCTV Pixel Density Calculator

When you install a new camera or reposition an existing camera, you must ensure that the new or repositioned camera will capture the necessary detail from the location where the subject of interest will appear in the video footage. Many people will automatically assume that installing a higher resolution camera or one with a wider lens will provide the necessary viewing detail for the desired surveillance task. However, the actual performance of a camera are determined by how many pixel fall onto the subject.

The pixel density of a camera can change based off the distance from the camera, the angle of the lens, and the width of the scene that the camera will cover. To calculate the pixel density of a camera, you must divide the number of pixels that the camera will record in the horizontal direction by the width of the scene that is to be covered by the camera. This calculation will provide the number of pixels per foot or pixels per meter.

Make Sure Your Camera Captures Enough Detail

The width of the scene can be directly measured with a tape measure, or it can be calculated from the angle of the lens and the distance from the lens to the scene. The width of the scene that is to be covered by the camera is the parameter that must be measured. Using the width of the scene that is to be covered by the camera will provide the most accurate calculation of the pixel density.

Using the total width of the scene that the camera is to cover will provide inaccurate results. Raw pixel measurements of cameras are different than the performance of the camera. The raw pixels are calculated under ideal conditions within the laboratory; the surveillance camera will often lose some of that potential resolution due to video compression, motion blur, and the subject being under-lit.

In order to account for the loss of resolution of surveillance cameras in the real world, an allowance for quality must be made in the calculation of pixel density. The quality allowance is a small amount that is subtracted from the calculated pixel density; this ensures that the calculated pixel density is the actual resolution that the surveillance camera will provide once it is installed and running. The pixel density of a surveillance camera will depend upon the task that the surveillance camera is to perform.

The task of detecting that an individual is in a particular scene will require fewer pixels than a task of recognizing the license plate of a car or the face of an individual. Guidelines have been established for surveillance cameras for the various tasks to ensure that the resolution of the surveillance camera is appropriate for the task. A task that only requires detection of motion will have a lower pixel density than a task that requires the recognition of an individual.

The pixel density can be increased by decreasing the scene width that is to be covered by the surveillance camera or by using a narrower lens. The scene width that is to be covered by the surveillance camera and the lens that is used are two variables that interact with each other. A wide-angle lens will cause the pixel density to drop quickly as the distance from the surveillance camera to the subject increases.

A narrower lens will increase the pixel density of the surveillance camera, even though the lens covers less of the scene. Calculators are available that allow for the calculation of the scene width from the angle of the lens and the distance from the surveillance camera. The surveillance camera will help to determine the proper lens that should be used to provide the required pixel density within the scene width.

The distance that the surveillance camera is to be installed from the subject will impact the viewing angles of the surveillance camera. The surveillance camera can determine how wide the angle of view should be based upon the distance from the surveillance camera of the subject that is to be viewed. The scene width can be measured at the subject rather than at the surveillance camera.

The scene width measured at the subject will provide the most accurate calculation of the surveillence cameras viewing angle. The resolution of the surveillance camera also interacts with the calculation of the pixel density. If the resolution is increased from 1080p to 4K, for example, the horizontal pixels will be doubled.

However, if the 4K resolution is used to cover the same scene width as the 1080p resolution, there will be no benefit to using the higher resolution. The pixel density calculation can determine the resolution that is required to view a subject at a given distance. In some cases, changing the lens will provide more benefit to the surveillance camera than increasing it’s resolution.

Some common mistakes in calculating the pixel density of surveillance cameras include incorrect assumptions regarding the scene width and the distance from the surveillance camera. For example, rather than measuring from the surveillance camera to the subject, many individuals will measure from the surveillance camera to the entire driveway. Additionally, the distance from the surveillance camera to the measurement plane may be measured rather than the distance to the subject.

Finally, individuals may not account for the loss of focusing precision of surveillance cameras that use wide angle lenses; the pixel density in the corners of the surveillance camera may be less than that in the center. Each of these mistakes will result in an incorrect calculation of the pixel density of the surveillance camera. Lighting and the angle of the subject will impact the outcome of the surveillance camera feeds.

However, these variables are not accounted for in the calculation of the pixel density of the surveillance camera. For example, a surveillance camera focused on the subjects of individuals will lose focusing precision if the subject’s face is turned away from the surveillance camera. Additionally, the individual may lose detail if their face is lit from behind the surveillance camera.

Furthermore, if the shutter speed of the surveillance camera is too slow for the subject that is being viewed (such as a moving vehicle), the resulting motion blur will make it difficult for surveillance software to focus on the subject’s features. The goal in planning the surveillance camera feed is to ensure that there are enough pixels falling onto the areas of interest to the surveillance task. Some surveillance cameras require fewer pixels than others.

A surveillance calculator will make it easier for surveillance camera designers or installers to determine the number of pixels required by the surveillance task. Once the calculated pixel density of surveillance cameras matches the pixel density requirements for the surveillance task, it will be easier for the designer or installer to determine the mounting height of the surveillance camera, the lighting requirements for the area, and the surveillance camera recording settings. You should of checked the lux levels too.

It is easy to make a error when your setting up a new system. There are alot of factors to consider. One should of also looked at the furnitures in the room to see if they blocks the view.

The cameras needs to be placed high. One mistake people make is using a lens that is too wide. The results will be bad if the camera is too far.

The installers often forget to check the cables. This can lead to a problem.