Overview
IEC 61146-4:1998 is an International Electrotechnical Commission (IEC) standard that establishes methods for assessing the automatic functions of video cameras and camera-recorders operating with PAL, SECAM, and NTSC systems. The standard specifically focuses on automatic functions related to light input through the lens and the electronic output from video cameras and their recorder components. By defining standardized test patterns, conditions, measurement methods, and ways to present results, IEC 61146-4 enables objective, repeatable comparison of camera automatic functions such as automatic exposure, focusing, and white balance.
Key Topics
- Automatic Function Assessment: Covers procedures to measure and evaluate key automatic functions in video cameras and camera-recorders, ensuring results are only for the aspects relating to lens light input and electronic video output.
- Standardized Test Patterns: Specifies the use of particular test charts, such as grey scale charts (with γ = 2.2), tracking charts, and uniform white or resolution charts, to provide consistent measurement conditions.
- Measurement Conditions: Sets out controlled requirements for environmental conditions, illumination (color temperature and intensity), camera positioning, and equipment setup.
- Result Presentation: Details how to present measured data, such as absolute signal levels and relative variations, in standardized tables for easy comparison between devices.
- Automatic Exposure Control: Provides methods to assess how luminance signal levels respond to changes in illumination and average scene brightness.
- Automatic Focusing: Describes assessment techniques for focus response time and accuracy under standardized conditions.
- Automatic White Balance: Outlines procedures for measuring the dependency of white balance on color temperature and its dynamic characteristics.
Applications
- Product Development and Quality Assurance: Manufacturers of PAL, SECAM, and NTSC video cameras and camera-recorders can use IEC 61146-4 to objectively benchmark the performance of their products’ automatic functions.
- Comparative Testing: Testing laboratories and certification bodies can consistently compare different video devices, supporting reliable product claims and buyer confidence.
- Procurement and Specification: Professional users and system integrators can reference IEC 61146-4 methods to specify and select video cameras and camera-recorders with verified automatic function performance.
- Research and Development: Engineers and developers can utilize the standardized test methods outlined in IEC 61146-4 to improve auto-exposure, autofocus, and white balance features, enhancing the user experience.
- Technical Documentation: The standard’s definitions, test procedures, and result reporting structure assist in the creation of comprehensive, transparent product test reports.
Related Standards
- IEC 61146-1:1994 – Video cameras (PAL/SECAM/NTSC) – Methods of measurement – Part 1: Non-broadcast single-sensor cameras. Lays the groundwork for many fundamental measurement techniques referenced in Part 4.
- ISO 8341:1989 – Photography – Slide projectors and filmstrip projectors – Illumination test. Provides standard methods for measuring and specifying illumination, referenced for environmental and measurement conditions in IEC 61146-4.
- IEC 60050 – International Electrotechnical Vocabulary (IEV). Used for unified terminology across IEC publications.
- IEC 60027, IEC 60417, IEC 60617 – Address graphical, letter, and schematic symbols for clarity in documentation and reporting.
Practical Value
Adopting IEC 61146-4:1998 assures that the automatic exposure, focus, and white balance functions of video cameras and camera-recorders can be measured and compared on a level playing field. This standardization is critical for delivering reliable, quality-controlled video equipment for professional and consumer markets, supporting enhanced imaging performance and consistency across various operational conditions. By adhering to IEC 61146-4, both manufacturers and buyers benefit from increased transparency and confidence in automatic video camera functions.