Testing The Real Resolution of MP Cameras (Line Count)

By: Ethan Ace, Published on Dec 11, 2013

Resolution has problems.

IP cameras equate resolution with pixels, ignoring that pixels are simply mechanical components of a camera, not the full performance of said camera. Indeed, it has gotten so bad, we have recommended that we Ban Resolution.

Classic Resolution Metric

With analog cameras, resolution was always defined by line counts (aka TV line counts or horizontal TV lines), which measured the actual details that the full camera could deliver.

In fairness, line counts were far from perfect. They only considered ideal lighting conditions and ignored digital recording. Plus, manufacturers went crazy with them, leading to analog insanity of spiraling, but pointless, TV line counts of 600 to 700 to 800 to 900 to 1000.

However, at least line counts attempted to measure real world performance, not just count parts on a chip (i.e., number of pixels = resolution).

The IP TV Line Test

IPVM is bringing back the TV line test and introducing it to IP / MP cameras.

The setup is an ISO 12233 chart with a camera positioned to capture the area of the chart. The image below shows an IP camera being tested:

We then measured the number of TV lines different cameras delivered in various conditions. Here is an example of two test charts:

Get Notified of Video Surveillance Breaking News
Get Notified of Video Surveillance Breaking News

Notice that in chart 1, the number of TV lines visible is ~450-500 while chart 2 on the right is much higher, 1,000-1,200.

Questions Answered

This test answers the following key questions:

  • How does pixel count relate to line count?
  • How much are line counts reduced in lower light?
  • How much does compression impact line count?
  • What other factors impact line count?

Key Findings

Here are our key findings from this test:

  • Pixel count had the largest effect on TV lines captured, an increase of hundreds of TVL for each jump in resolution (720p to 1080p, 1080p to 5MP, etc.).
  • Lowering lights significantly impacted cameras at all resolutions, on the order of hundreds of TVL when lights were dimmed to 3 lux and below 1 lux.
  • Compression surprisingly had no practical effect. Edges of large objects of the chart suffered artifacting but the fine lines used to measure TVL were still distinguishable even at maximum compression.
  • Lens selection had substantial impact, with differences of 100-200 TVL possible moving from SD to megapixel to multimegapixel lenses.
  • Adjusting sharpness had minor effect, typically only reducing TVL count when lowering it to minimum levels. Increasing above defaults had no practical effect.
  • Other image adjustments such as contrast and saturation had minimal effect, with no difference in TVL captured.

Readers should note that we have included ranges of TVL in this report, as opposed to exact measurements, since interpretation of these results may be subjective and vary somewhat from person to person.

Test Setup

This short video reviews our physical setup of the test and use of the chart.

Summary Findings

This chart lists the TVL we found for each camera in different lighting conditions:

Based on the above numbers, pixel count relates to TVL in a ratio of approximately 1:0.41 in full light. So for example, given a 5MP camera with a horizontal resolution of 2560, we can estimate TVL captured to be ~1,049 (2560*0.41=1,049). 

Pixel Count Comparison

As a baseline, we set up our cameras in a brightly lit room beneath indirect lighting. Cameras were tested one at a time to properly adjust FOV and mounting angle to the chart, and default settings were used.

As seen in the comparison below, TVL varied from ~450-550 in 720p to ~1,400-1,600 in the 10MP camera.

(click for full size version)

Lowering Light

Next, we lowered the lights to 3 lux to test effective TVL captured as light dims. Cameras were standardized to 1/30s exposure in these low light scenes.

TVL dropped substantially in all cameras. The 1080p camera best maintained performance in this scene due to a combination of low light performance and resolution. 

(click for for full size version)

With the lights off, the light level drops to about 0.1 lux. Only the 720p and 1080p cameras produce usable images at this level, again at a reduced performance level, with the 720p camera dropping to ~200-300 TVL, and 1080p camera to ~550-600. 

(click for full size version)

Compression

In order to test compression's effects on TVL captured, we varied settings from minimum to maximum (0-100, with a default of 30 in the Axis camera seen below). These changes had little effect on TVL. More compression artifacts were seen on the edges of some larger objects on the chart, but the fine lines used to measure TVL remained mostly unchanged regardless of compression.

Further, we checked for differences between H.264 and MJPEG, which also had no practical effect, further proof that H.264 is inherently not lower quality than MJPEG.

Lens Type

In order to see what effect lens selection had on TVL captured, we ran the test using a 720p camera with four different lenses: one standard definition, two megapixel rated, and one "ultra high definition" multi-megapixel rated lens. We found that lens selection had the second largest impact on TVL captured, after pixel count, with a variance of 300+ TVL possible moving from standard definition lenses to multi-megapixel. Additionally, even our two megapixel rated lenses (Computar and Fujinon) resulted in different TVL ratings (450-550 vs. 500-600). 

(click for full size version)

Lenses used were (L-R):

Image Settings

Finally, we checked the impact of image adjustments such as contrast, sharpness, and saturation on TVL.

Among these, only sharpness had noticeable effect, slightly reducing TVL when it is lowered to minimum from default. Increasing from default to maximum provided no gain in TVL.

 

Contrast and saturation, on the other hand, had no noticeable effect regardless of setting.

1 report cite this report:

Resolution Tutorial on Dec 28, 2017
Understanding video surveillance resolution can be surprisingly difficult and complex. While the word 'resolution' seems self-explanatory, its use...
Comments (25) : Members only. Login. or Join.

Related Reports

Video Surveillance Cameras 101 on Feb 25, 2020
Cameras come in many shapes, sizes and specifications. This 101 examines the basics of cameras and features used in 2020. In this report, we...
Glossary / Acronyms for Video Surveillance on Feb 10, 2020
This directory provides definitions and explanations for over 70 common video surveillance industry terms, including links to related IPVM...
IR Surveillance Camera Guide on Feb 06, 2020
Integrated infrared (IR) cameras are everywhere in 2020, but not all IR is created equal, with many differences in coverage, overexposure,...
Biggest Low Light Problems 2019 on Nov 08, 2019
Over 150 integrators responded to our survey question: "What are the biggest problems you face getting good low-light images?" Inside, we share...
Wide Dynamic Range (WDR) Guide on Oct 01, 2019
Understanding wide dynamic range (WDR) is critical to capturing high quality images in demanding conditions. However, with no real standards, any...
Avigilon 32MP and 12MP H4 Multisensor Cameras Tested on Jun 11, 2019
Avigilon has released their H4 Multi-Sensor line of cameras claiming "broad scene coverage and high image detail" We bought and tested the...
Vivotek 20MP Multi-Imager Tested on May 30, 2019
Vivotek has released their latest repositionable multi-imager camera, the MA9321-EHTV, a 20 MP model claiming "Supreme Night Visibility", "Optimal...
Verkada Video Quality Problems Tested on May 23, 2019
Verkada suffers from numerous video quality problems, not found in commercial IP cameras, new IPVM testing of Verkada vs Axis and Hikvision...
Panasonic 32MP Multi Imager Camera Tested (WV-X8570N) on May 16, 2019
Panasonic has released their first multi imager models including the 32MP (4x4K) WV-X8570N, claiming "Extreme image quality for evidence capturing...
Speco Ultra Intensifier Tested on Apr 22, 2019
While ISC West 2019 named Speco's Ultra Intensifier the best new "Video Surveillance Cameras IP", IPVM testing shows the camera suffers from...

Most Recent Industry Reports

LIVE Now "Fever Camera" Show Day 2 on Jun 03, 2020
IPVM is excited for the world's first "Fever Camera" show. Day 2 is today from 11am to 4pm EDT. Recordings from Day 1 are posted at the end of this...
Cobalt Robotics Presents Indoor Security and Access Robots on Jun 03, 2020
Cobalt Robotics presented indoor security robots at the May 2020 IPVM Startups show. Inside this report: A 30-minute video from Cobalt...
Dahua Sues Ex-North American President, Says Legal Typo on Jun 03, 2020
Dahua's former North American President Frank Zhang claims he is owed almost $11 million but Dahua counter claims it is just a "scrivener's error",...
Smart Entry Systems Presents Cloud Multi-Tenant Access Control on Jun 02, 2020
Smart Entry Systems presented Cloud Multi-Tenant Access Control at the May 2020 IPVM Startups show. Inside this report: A 30-minute video...
Genetec Drops Support for Dahua and Hikvision on Jun 01, 2020
Genetec has dropped support for Dahua and Hikvision, citing US blacklisting and ONVIF conformance blockage, the company informed partners in an...
Dotty "Hot Or Not" Elevated Body Temperature App Tested on Jun 01, 2020
What if you could take an existing phone or tablet and transform it into "fever camera"? That is what DottyAR is doing with their strangely named...
Optris "Fever Screening Systems" Examined on Jun 01, 2020
German manufacturer Optris has been building temperature measuring instruments for industrial manufacturing for over 15 years, and thermal cameras...
Fever Camera Sales From Integrators Surveyed on Jun 01, 2020
Fever cameras are the hottest trend in video surveillance currently but how much are integrators selling them? 220 integrators answered the...
Proxy Presents Mobile Credentials For BLE Devices and Access on May 29, 2020
Proxy presented Mobile Credentials For BLE Devices and Access at the May 2020 IPVM Startups show. Inside this report: A 30-minute video...
ISC West 2020 Moves To The Basement on May 29, 2020
The twice cancelled/postponed show will now not only be held in a different month (October) but on a different floor, moving down to the...