May 26 2010
The leading imaging technology vendor Pixim has recommended the latest horizontal TV lines (HTVL) Effective (HTVL-E) specification that accounts for expressing both vertical TV lines (VTVL) and HTVL as the CCTV cameras’ single resolution number in response to new technologies and latest trends in the industry.
This novel specification provides video security cameras the complete credit for the full, usable image created by them and also maintaining compatibility with conventional HTVL nomenclature. Using the HTVL-E standard will empower the security consultants and end users to compare the useable resolution provided by different cameras irrespective of the image capturing technology in use.
Frost & Sullivan, a research and consulting firm, has endorsed the HTVL Effective specification that is the most recent measurement methodology of the resolution of the CCTV camera. This specification utilizes the HTVL’s and VTVL’s measured values for finding out the CCTV cameras’ actual and useable resolution.
Resolution is usually specified in terms of HTVL in the video security market. Vertical resolution is also important though rarely specified, and is used to calculate an image’s total resolution. The measured vertical resolution multiplied by the measures horizontal resolution results in the total resolution. The interfaced image sensors’ limitations were responsible for the rare mention of the vertical resolution in the past. However, wide spread usage of progressive scan imagers has resulted in the importance of vertical resolution as a key component of the total resolution, resulting in the need for a novel resolution specification for the CCTV camera.
Analog CCD sensors are capable of capturing interfaced video through use of the line-pair simulation process. However, this technology causes a side effect that decreases the vertical resolution by 25%. Such a decrease is regrettable for the end users since inputs of DVR and display monitor can accept 480 vertical resolution lines. In contrast, imagers that are capable of capturing progressive images can maintain the complete vertical resolution resulting in increased total resolution during playback and initial display. Cameras used outside the security industry are usually specified by total resolution.
The HTVL’s significance as an autonomous stand-alone resolution standard has been reduced by the emergence of digital image sensors, recorders and display devices.
Frost & Sullivan has approved the standard’s extensive usage for the video security industry since it can use any image sensor type for simple measurement on any CCTV camera.
Source: http://www.pixim.com