Image Quality Factors

Sharpness

Brand：ColorSpace
Product description: Sharpness is arguably the most important single image quality factor: it determines the amount of detail an image can convey. The image on the upper right illustrates the effects of reduced sharpness
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Clarity is a crucial factor in assessing image quality, indicating the capability of an imaging device to capture and display the sharpness of an image and its fine details. The clarity of a device or system can be measured through Spatial Frequency Response (SFR), also known as the Modulation Transfer Function (MTF). The MTF quantifies the contrast at specific spatial frequencies, which can be expressed in terms of cycles per unit of distance or line pairs per unit of distance.

There are three prevalent methods for testing the clarity or resolving power of an imaging system: TV line testing, MTF testing, and SFR testing. Clarity dictates the level of detail an image can convey. The image below illustrates the impact of reduced clarity. The clarity of a device or system is determined by measuring its SFR, or MTF. The 50% MTF value correlates well with visual clarity and is a more effective approach than traditional methods that focus on the point at which details vanish, as it emphasizes the consistency of the image's sharpness.

In practical testing, there are differences in the sharpness test charts required by various standards. Some commonly used ones include the ISO12233 test chart, SFRplus test chart, eSFR ISO test chart, SFRreg test chart, andthe Siemens star test chart.


ISO 12233 Test Chart	SFRplus Test Chart

eSFR Test Chart	SFRreg Test Chart

ColorSpace offers a variety of test equipment and analysis software for sharpness testing, supporting the following standards, among others:

· ISO 12233 Standard: Photography - Electronic still picture imaging - Resolution and spatial frequency responses
· QC/T 1128 Standard: Cameras for automotive use
· GA/T 1127-2013: General technical requirements for video surveillance cameras in safety prevention
· GB/T 31070.1-2014: Building intercom systems
· Zoom Meetings Personal Camera v4.0
· Microsoft Teams Video Specification 5.0