The PPF / PPM Video Surveillance Guide

By: IPVM Team, Published on Dec 23, 2016

Pixels per foot / Pixels per meter is the most fundamental and valuable, though imperfect, metric for specifying video surveillance image quality.

In a single number, this metric (e.g., 10ppf, 40ppf, 100ppf) conveys important information about what the projected quality that a camera can provide.

The image below, taken from our Camera Calculator, demonstrates examples of common pixel per foot (ppf) levels:

PPF Established Metric

PPF has become a critical established metric for several reasons:

  • Broad camera manufacturer support: Most major manufacturers use this metric.
  • Common A&E specifications: Architects and engineers who plan large projects regularly use PPF / PPM as the basis for their designs and surveillance plans.
  • Need for Something: With so many resolution options today (from 1MP to 12MP and beyond), the old metrics which used percentage of screen covered make no sense. PPF has filled this void.

The Goal of PPF

PPF is a single metric (e.g., 10, 50, 90, etc.) that when specified should deliver a specific level of quality. For example, the parking lot camera must deliver 50 PPF. Instead of guessing or just specifying more resolution, using this metric should enable selection of the ‘right’ resolution for the scene. The final image, following the PPF metric, will then deliver a predictable level of quality.

PPF Problems

Alas, PPF suffers from many problems that must be factored in:

  • Assumes even lighting and ignores the impact of bright sunlight
  • Assumes day time lighting and ignores the impact of night time / low light viewing
  • Disregards differences in lenses and compression
  • Disregards that image quality needs are subjective and debatable
  • Fails to specify related and critical metrics to complement PPF

Despite this, PPF does have value for estimation and planning. It just cannot be used blindly or simplistically. Inside the PRO Member’s section, we explain:

  • How to calculate PPF
  • How to recognize PPF limitations and make adjustments
  • How to best use PPF productively

Key ***************

**** ** ****:

  • *** ** *** **** art **** *******. *** are ******* ******** ** you ***** * ****** number *** *** ***** to ********** ********* ** complex ** ***** ******* across ********** *** ******.
  • ********** *** *** *********** of **** ** *** can ***** ********.
  • *** *** ** * baseline ** *** * sense ** ********* *********** then ****** *** ******** site ********.
  • *** *** ****** ***** guarantee ******* ****** **/*/*** in ***** ************.
  • *********** *********** *** *** proper ************.
  • ** *** ************ ** improve ********* *** ***** using **** ** **************. Instead, ******* ********** *** key ****** ********** (***, low ***** ***********, ***.)

PPF ** ***

****, ** *** *** throughout **** ******, *** sometimes *** ****** **********, Pixels *** ***** (***), is ****. *******, *** is ******** ****, **** in **** ******* ************ on *** ****** ******.

*** *********, *** ***** below ***** **** ******** PPF ****** *** **********. Note **** ******* ****** ************** ******** ****** ************, in ******** ** ******** / ***.

How ** ********* ***** *******

*********** ***** ******* ******* on *** ******/*******:

  • *** ****** ** ********** pixels ** * ***** feed/camera
  • *** ***** ** *** FoV ** *** ****** at *** ***** ** interest

Horizontal ***** *****

** ******* ** ******** identify *** ********** ***** count *** ** *** confuse ** **** *** vertical *** *** ******* resolution. *** ********, * 720p ****** *** * total ********** ** *** (technically *.***) *** *** horizontal ***** ***** ** 1280 *** *** ******** pixel ***** ** ***, more ******** ********* ** 1280 * ***. ** is *** ***** ****** in **** ****, *** 1280, **** ****** *** measuring ***.

**** *** ********** ***** counts *** ****** ***********:

**** **** ** ******** them ** **** *** quite ***********.

Selecting *** *****

*** ****** **** ** the *********** ** *** wide * ***** ** View *** ***** ** cover. *** ***** ***** shows * ****** ******** for ********* *** ***, simply ******* ****** ** the ***** ** ********, like *** **** *****:

*********** *** ***** ** the *** *** ** trickier *** ******, **** areas, **** ** ******* lots ** ******. *** instance, *** ********* ***** shows *** ********* *** widths *** ******** * parking ***/*****.

**** ** ***** **** may ** '*****', *** it ******* ** ******** factors.

  • ** ***** ******* ***** the ****?** ******* ****** ** mounted ** *** ***** of **** ***, ****** to *** **** ** the ****** *****, ** may ** ****** ** use *** ******** ***' FOV *** ************. ** there ** ** ***** coverage, *** ***' *** need ** ** ****.
  • **** ********** *********** *** there?** ****** ********* ** limited ** ***********, ** must **** **** ** mind **** ********* ****. This *** ** *** if ***** *** ***** models *** ********, ***** are ********* ******* ** 1080p. *** ** ** or **** ******* *** be ****, ***** **** are ********.

** ***** ** *** uncertainty, ** ********* ***** wider ****, ** **** you ** *** ************* your ***.

PPF *******

**** *** **** ********** the ********** ****** ** the ****** ****** *** measured **** *** *****, PPF ** ****** ********.

**** *** * *** examples:

  • *** *** ***** * 720p ****** ** ***** a ** **** **** entrance: *** = *** because ********** ***** ***** is **** *** *** Width = ** (*.*., 1280 / **).
  • *** **** * *** camera ******** * *** foot **** ******* ***: PPF = ~** ******* horizontal ***** ***** ** 2592 *** *** ***** = *** (*.*., **** / ***).
  • * ***** ****** ** monitoring * ** **** wide ******* ********: *** = ** ******* ********** pixel ***** ** **** and *** ***** = 40 (*.*., **** / 40).

PPF ********* ** *** ***** *** ******** **** ****** *********

******* ** *** **** a '******' ***. **** the *** ** ******* on *** *** *** subject ** ******** ** from *** ******. *** instance, ***** ******* ****** **********, ** *** ***** over * ******'* ***, which ***** *** ** that *****. ** *** see **** *** ********* as ** ******** *** target ** ** ***, but ******* *** ****** it ******* *********, ** 100, ***, ** *** PPF.

******* *********, *** *** level ********* ** ** widen *** ***, **** below. ******** *** ****** of *** *** *****, we *** *** *** decrease, *********** ** ***.

*** *** *** **** for ******** ** ******* ****** **********.

Fisheye ***** ** **** ******

*******, ****** ** ***** of **** ***** **** using ******* ********* ******, as *** ***** ************, much ****** **** ******** cameras.

***** *** (*) *** cameras ** ** *******, one * ******* ********* (360 ****) *** *** other ***** * ~**° HFoV. ******* *** **** to *** ** ******** 20 **** **** **** each ******:

  • **** * *** *********, at ** **** **** from *** ******, *** PPF ** ~**
  • **** * *** '************' 60° ****, ** ** feet **** **** *** camera, *** *** ** ~130

**** ** * ******* practical **********. ***** *** panoramic *** *** ** 'all' **********, ** *** direction, ** ** **** away, ****** **** **** like ***** (**** **** scenario). ** ********, *** 'conventional' **** **** ******* near ******** ******* ****** though ****** * **** narrower ****.

*** *** **************** ********* ****** *********** **** *******.

Recognizing *** ***********

**** ***** *********** ***, there *** ******* ****** which ****** *** ********* quality ** ****** *********. Below, ** ******:

  • *** ****** ** ****** lighting / **** ******* scenes
  • *** ***** / ***** time *******
  • *********** / ***** ******* setting ******
  • **** ******* ***********
  • ********** ***** ******* ************
  • ************* ******* ** ***

Wide ******* ***** ***********

*** ******* *** ****** are *** **** *** the ********* ***** *** vary *************. *** ******* to ****** ****** ********* / ******** ** * key *******. ** *** image *****, **** ******* have *** **** **********, cover *** **** *** and *** ***** ** the **** ****:

*******, *** ***** ** the ***** ***** **** it *** ***** *** PPF ***** ** *** other. ****** *** *** is *** ****, *** camera ** *** ***** has *** ******** *** more ********* ***.

Low ***** ***********

**** ** **** ********** low *****, ** **** as ****,****** ********* **** ****************, **** ******* ***** reducing ***** *******. **** can ** **** ** the ****** ** ****** below, ******* *** ******* in *** **** **** over *** ****** ** several ***** **** *** to *****, **** ***** levels ******** ** ~*,***** on *** ****, *** under *** ** *** right.

******* *** ***** *** being '****' ** ******* standards, **** *** **** cameras ******* ***** ******* and ******* **** ***** than ****** *** ***. However, ************ *** ********** almost ***** **** **** critical ********** *****.

** *** ****** **********, we ******* ******* ***** in **** ***** *** and ***** ****** ** show **** **********, **** PPF ********* ** **** time ** ***** ****** their *******' **********.

Differences ** ***********

******* *** ********* ******* with *** ** *********** level ********. **** ** the **** ********** *** the **** ***** *** used, *** ****** ** compression *** **** *******. Below ************ ****:

** ***** **** ***** B's *** ** *** lower **** ***** *, but **** ** *** the ****. *** *** less *** **** ***** A *** **** ** not *** ****. **** images *** ***** **** the **** ******, **** the **** ********** ***** increased *********** ** ***** B.

****** ** *** ********* confusion, ************* *** **** different ******* *********** ********, as **** ** ********* terminology *** ***** ******* quality ******. ******* ****** see ***** ****** ************ *********** Comparison*** ******* ** ***** settings *** ************ *****.

***** ****** ** ******* to ***** *********** ****** and******* ************* ********* ** ***** these ******** ******. *** our***** ******* / *********** Tutorial*** **** ******* ** compression *** *** *******.

Lens ***********

**** ***** **** **** choices *** **** * huge ********** ** ***** quality, ********** ** *** pixels ********. *******, ** our *****, **** ******* is ****** * ***** concern, ******* **** ******* differences ***** *** *********** in **** ******. ***** factors, **** ***-****,******, *** ********** ************ are *** **** ****** to ****** ***** *******.

Subjective ***** *******

******* *** **** ********** element ** *** ** how ********** *** '*****' quality ***** *** **. Just ** '****** ** in *** *** ** the ********', *** ********** person *** ***** * given ******* ***** ** good ****** ** '********' a *******, *** ******* may ******* ************* **** pixels ** ****** *** required.

*** *******: * ******** wants ** ****** * human *******. ***** ** the ***** *** ****** below ** *****?

***** **** ** **** show ****** ******* *** all ** **** **** at ***** ** *******, some ***** ****** *** 18 ** ** *** images, ** **** **** more **** **** * moving '****', **** **** very ***** *******.

*** **** ********* ******** arises **** ******** ******* how **** ****** *** needed ** ******** * specific ******. ******* *** images *****:

**** ****** **** *** the ~** *** ** the **** ** *** fuzzy *** **** **** want * '*******' *****. Others **** **** ** good ******, ********** ** the ****** ** *****, such ** ** ******** or ********.

********** ** **** ** 'expert' ****** ** ******, one ***** ** ****** with *** ***** / decision ***** **** **** think ** **********.

Related / ******** *******

**** ********** *******, *** alone **** *** ******* enough *********** ** ******** select *******, ******* ** confusion ** *********. **** using ***, ******* ******* must ** ****:

  • ***** ** **** *****: ***** ************** **** to ****** *** *** the *** ***** ** be, ********* **** * PPF ******. **** *** create ********* ** **** will *** ******** ** wider **** **** ******. Instead, ************ ***** *** wide, *.*., ** *** at ** ****, ***.
  • ******** ** ******: ******* *** *** the ****** ***** ** deliver *** ***** *** impacts **** ********* ** well ** *** ***** of *** ***. ********, the ******* **** **** the ****** *** ****, the ***** *** ***.
  • ***** ** *********: *******, ********** ** the ****** ** ******, if *** ****** ****** too ******* ********** ** horizontally, *** **** **** key ******* **** ***** or ******* ***** **********. In ********* ****** ** ***** Quality****, ** ********** **** 15° ** **** ** ideal *** ****** ****** images.

FOV **** **********

******* ** ********* ** resolution ***** ********* ******* were **********, *** ********* has ****** ****** *** smaller *****. *** *******, in ***** **' **** or ****, * ***** camera **** ******* ~******, more **** ****** ****** for * **** ******* day **** *****. ** contrast, ** *** **** using ** ** ******, to *** *** **** PPF, *** ***** **** to ***** **** *** width ** * **** wide - * **% decrease.

** *** ****** **** high, *** **** ********* issues *** *********** ********* such ** *** ******'* low ***** *** *** performance. ********, ***** ******* will ***** ******* **** bright ******** *** *** light *** *** **** number ** ****** ******** a '****** *** *****'.

Larger **** **** *********

*******, ***** **-** **** wide ****, *** ********* becomes **** ********. ****** up **** ***** ** a *** ****** **** increases *** ********** ***** count ********, ~**%. ******* importantly, ********* *** ***** and *** *********** ** 5MP ******* *** ***** than ***** ****.

** ******* ***** ********** PPF *** ***** ***** as ** *** ****** problems ** *** ***. For ********, ***'* *** you **** ***** ****** a *** **** **** area. ** ** **, you **** **** **** horizontal ******. * ****** 14MP ****** *********** **** (as ** *** ~**** horizontal ******) ** ***** (2) *** *******. *** best ******** ***** ***** be (*) ***** *******. While *** ***** *** is ******** **** (****), the ******* ******* *** be ******** ** ***, low *****, ***** ****, broad ******* *******, ***.

PPF ********** ******* ** *************

**** *** **** ** mind, *** ****** ******* to ************ *** **********.********:***** ******* ****** ******, even ******** *** ** not ****** ** *** impact ** ****** ******** or **** ****** ********, which ** ****** ************.

****** **********:

  • **** ******* / *********** people *** ******* ******:************* ******* ******* ** and *** ***. **** in ***** **********, ** is ******** ** ******* solid *********** *******, ********** of ******* ******. ** contrast, *** ** ****** overkill ****** ******** ** very **** ** **** fine ******* **** ** visible, **** ** *** serial ******* ** ********.
  • ******** ******* / ****** see **** ** ****** (person, ***) ** ***** but *** *** *********** details:************* ********* ********* ******* 20 *** ** ***. This ** ****** ********* as **** ** ******** is *****.
  • *** ******* / ********* only:************* ******* * - 10 ***. ** *******, because ** **** *****, it *** ** **** hard ** **** ******* out ****** *** ******* know **** **** *** there ** ** *** are ******* *********. ** course, **** **** ******** ideal ********. *** ** all, ** *** **** less **** ** ***, you *** ****** ****** to **** *******. *******, some ********* ******* **** a *** *** ** function, ** *** ***** be ****.

[****: **** ***** *** originally ******* ** **** but *** ******* ** 2016/2017 ** ******** ******* covered *** ******* ****** examples **** *** **** Camera **********.]

Comments (11)

However, in our tests, lens quality is rarely a major concern, despite fine quality differences which are perceptible in some lenses...

Has there been a specific test of lenses and their effect on apparent PPF?  Some tests have indicated that in certain cases there might be substantial differences, A Major Flaw in Long Lenses and PTZs Found.

Plus with imager pixel density increasing, lenses are needed to have higher MTF.  

You raise a good point. We'll add more info about long lenses and clarify.

Great article. 

Note, we use PPF throughout this report, but sometimes the metric equivalent, Pixels Per Meter (PPM), is used. However, PPF is commonly used, even in many regions standardized on the metric system.

This bias for anything non-metric forever bemuses me.

Setting aside your 'regional' comment for just a moment, there are only 3 countries in the world not using the metric system.  And with no offense to Burma or Liberia, it's the USA that you are acquiescing to here.  So I ask you (IPVM) to reflect on PPF versus PPM.  As 'the world's leading video surveillance information source, IPVM provides the best reporting, testing and training for 10,000+ members globally' [my emphasis on the areas in bold], who are you serving?  What is the more exact measurement tool?

You say, 'PPF is commonly used, even in many regions standardized on the metric system.  I wonder what you base that comment on?  More importantly, if that is true, could the reason be because PPF is what we are force fed?

The US National Institute of Standards and Technology (NIST) has a very interesting paper on the subject of metric systems in the USA at https://www.nist.gov/sites/default/files/documents/pml/wmd/metric/1136a.pdf

Thanks for your consideration and Happy New Year.

James,

Our calculator has long supported metric and actually checks the country for each visitor defaulting to metric for those countries who use metric.

We will add in references to PPM values as well as PPF for all pictures / graphics after the New Year's and update the post.

James, all, we added PPM measurements to the images inside the report. Thanks.

Can anyone explain why the Horizontal Pixel count of 2592, for 5MP resolution, is less than the figure of 2688, for 4MP resolution? 

This question is in reference to the table on page for of this tutorial.

Eddie, good eye.

The reason that 5MP has a lower horizontal pixel count than a 4MP camera is the difference in aspect ratios, i.e., 5MP cameras are 'taller' than 4MP ones:

5MP - 2592 x 1944

4MP - 2688 x 1520

Related - Aspect Ratio 16:9 vs 4:3 Shootout

Also, 3MP cameras have slightly greater vertical pixel count but much narrower horizontal one, i.e., 3MP - 2048 x 1536

Give a better idea of ppm.

I want to help, but I don't understand the question.  Can you expand?

Clear explanation of changes in HFoV and change of PPF according to difference parameter.  Great information.

Read this IPVM report for free.

This article is part of IPVM's 6,528 reports, 880 tests and is only available to members. To get a one-time preview of our work, enter your work email to access the full article.

Already a member? Login here | Join now

Related Reports

Emitted Energy TempScan Thermal Screening System Examined on Apr 28, 2020
Emitted Energy has specialized in temperature measurement using FLIR cameras...
Embedded Logix Thermal Temperature Detection System Examined on Apr 08, 2020
Embedded Logix has been producing thermal temperature measurement systems for...
Optris "Fever Screening Systems" Examined on Jun 01, 2020
German manufacturer Optris has been building temperature measuring...
Directory of 206 "Fever" Camera Suppliers on Aug 04, 2020
This directory provides a list of "Fever" scanning thermal camera providers...
Quantum Dots Potential for Surveillance Cameras Explained on Sep 08, 2020
Quantum dots are starting to be used in TVs for better images, but how will...
FLIR A Series Temperature Screening Cameras Tested on Jun 04, 2020
FLIR is one of the biggest names in thermal and one of the most conservative....
The Next Hot Fever Detection Trend - $100 Wall-Mounted Units on Jul 06, 2020
The first wave of the booming fever detecting market was $10,000+ cameras,...
FLIR Presents Dual Spectrum High Security Focused PTZ on May 01, 2020
FLIR presented its Elara DX-Series bispectral, visible and thermal, PTZ...
Avigilon Elevated Temperature Detection Camera Tested on Sep 17, 2020
Avigilon has entered the temperature screening market with the release of...
Kogniz Health Thermal Screening System on May 15, 2020
Kogniz, a Silicon Valley AI surveillance company is claiming to offer...
Hanwha 8K / 33MP Camera Tested on Sep 14, 2020
Hanwha Techwin has released an 8K / 33MP resolution camera, the TNB-9000 with...
New Axis M30 Cameras Tested on Mar 26, 2020
Axis has released a new generation of, for them, relatively low cost M30...
Camera Course Summer 2020 - Last Chance on Jul 18, 2020
This is your last chance to register for the Summer 2020 Camera Course. This...
IPVM Editorial Staff on Aug 01, 2020
IPVM has the largest and most experienced editorial team covering video...
NetApp Presents Hybrid Cloud Video Archive on May 11, 2020
NetApp presented its hybrid S3 cloud video archive at the April 2020 IPVM New...

Recent Reports

FLIR CEO: Many New Fever Entrants "Making Claims That The Science Just Won't Support" on Sep 22, 2020
FLIR's CEO joins a growing number calling out risks with fever / screening...
China Bems Temperature Measurement Terminal Tested on Sep 22, 2020
Guangzhou Bems (brand Benshi) is the manufacturer behind temperature...
Axis Exports To China Police Criticized By Amnesty International on Sep 21, 2020
Axis Communications and other EU surveillance providers are under fire from...
Milestone XProtect on AWS Tested on Sep 21, 2020
Milestone finally launched multiple cloud solutions in 2020, taking a...
Mobile Access Control Usage Statistics 2020 on Sep 21, 2020
Most smartphones can be used as access control credentials, but how...
Axis Compares Fever Camera Sellers to 9/11 on Sep 18, 2020
Axis Communications, the West's largest surveillance camera manufacturer, has...
Avigilon Elevated Temperature Detection Camera Tested on Sep 17, 2020
Avigilon has entered the temperature screening market with the release of...
Chilean Official Investigated for Motorola And Hikvision Contracts on Sep 17, 2020
A corruption investigation is underway in Chile after a crime prevention...
Huawei HiSilicon Production Shut Down on Sep 17, 2020
Huawei HiSilicon chips are no longer being manufactured or supplied to...
Virtual ISC West and GSX+ Exhibiting Contrasted on Sep 17, 2020
Both ISC West and ASIS GSX are going virtual this year, just weeks apart, but...
X.Labs Sues FLIR on Sep 16, 2020
X.Labs, the maker of Feevr, has sued FLIR, the publicly traded thermal...
Video Surveillance 101 September Course - Last Chance on Sep 16, 2020
Today is the last chance to sign up for the Fall Video Surveillance 101...
No Blackbody Mistake, Half Million Dollar, Hikvision Fever Camera System in Georgia on Sep 16, 2020
A Georgia school district touted buying Hikvision fever screening "about...
Costar Technologies / Arecont H1 2020 Financials Examined on Sep 16, 2020
Costar's financial results have been hit by the coronavirus with the company...
Startup Cawamo Presents Live Alerts With Edge AI and Cloud VMS on Sep 15, 2020
Cawamo, an Israeli edge-to-cloud analytics and VMS startup, presented its...