GB/T 44268.1-2024 Microscopes—Definition and measurement of illumination properties—Part 1: Image brightness and uniformity in bright field microscopy (English Version)
GB/T 44268.1-2024 Microscopes - Deifinition and measurment of illumination properties - Part 1: Image brightness and uniformity in bright field microscopy
1 Scope
This document specifies procedures for the measurement of image brightness and uniformity for bright field light microscopy. These measurements for image brightness and uniformity are defined in image planes or intermediate image planes only, when these planes are suitable for detection by electronic imaging devices.
This document defines how image brightness and uniformity are measured and how this information is provided to the user.
Note: The scope is intentionally limited to electronic imaging devices and (intermediate) image planes. The visual observation by means of eyepieces would require a different measurement procedure and hence result in unambiguities in the description of measurement procedures. Nevertheless, this document will give useful estimates for the image brightness with visual observation as in this case, an eyepiece is used to observe an intermediate image plane (which is under the scope of this document).
2 Normative references
There are no normative references in this document.
3 Terms and definitions
No terms and definitions are listed in this document.
4 Measurands
4.1 General
For obtaining the desired image quality when using a light microscope, the brightness and uniformity of the image play an important role. This holds true for different applications and various types of instruments.
Intentionally, this document is limited to bright field microscopy and detection by means of electronic imaging devices but within this limitation, this document does apply to transmitted or reflected light microscopy and conventional or laser illumination.
4.2 Brightness
The image shall be bright enough to allow the detection of the details of the object under investigation.
Note: This is especially true for microscopic contrasting techniques like phase contrast, differential interference contrast, dark field microscopy, or fluorescence microscopy. Although these contrasting techniques are beyond the scope of this document, the given concepts can be easily extended.
As this document is based on measurement procedures, the image brightness shall be expressed in the corresponding SI units. The photometric unit Illuminance (measured in 1m/m2) shall be used whenever the illumination source covers the visible spectral range (380 nm to 780 nm) continuously, which is usually the case for filament and halogen lamps as well as for phosphor-type white LEDs. The radiometric unit irradiance (measured in W/m2) shall be used for all other illumination sources (like discharge arc lamps, lasers, and single colour LEDs) and are more generally applicable, e.g. to the ultraviolet and infrared spectral range.
4.3 Uniformity
The microscope’s optical system shall achieve a certain degree of image uniformity in order to allow the detection of the details of the object under investigation. A severe drop of the image brightness towards the edge of the image field can result in brightness values that are not sufficient in the above mentioned sense.
Furthermore, spatial variations of the image brightness over the image field cannot always be distinguished from spatial variations of the properties of the object under investigation.
The uniformity of the brightness in the image field is expressed as
Note: Depending on the size of the image field, the objective magnification and the size of the sensor pixels, it might be necessary to apply an adequate averaging method in the computation of the uniformity.
Standard
GB/T 44268.1-2024 Microscopes—Definition and measurement of illumination properties—Part 1: Image brightness and uniformity in bright field microscopy (English Version)
Standard No.
GB/T 44268.1-2024
Status
valid
Language
English
File Format
PDF
Word Count
7000 words
Price(USD)
210.0
Implemented on
2025-3-1
Delivery
via email in 1~3 business day
Detail of GB/T 44268.1-2024
Standard No.
GB/T 44268.1-2024
English Name
Microscopes—Definition and measurement of illumination properties—Part 1: Image brightness and uniformity in bright field microscopy
GB/T 44268.1-2024 Microscopes - Deifinition and measurment of illumination properties - Part 1: Image brightness and uniformity in bright field microscopy
1 Scope
This document specifies procedures for the measurement of image brightness and uniformity for bright field light microscopy. These measurements for image brightness and uniformity are defined in image planes or intermediate image planes only, when these planes are suitable for detection by electronic imaging devices.
This document defines how image brightness and uniformity are measured and how this information is provided to the user.
Note: The scope is intentionally limited to electronic imaging devices and (intermediate) image planes. The visual observation by means of eyepieces would require a different measurement procedure and hence result in unambiguities in the description of measurement procedures. Nevertheless, this document will give useful estimates for the image brightness with visual observation as in this case, an eyepiece is used to observe an intermediate image plane (which is under the scope of this document).
2 Normative references
There are no normative references in this document.
3 Terms and definitions
No terms and definitions are listed in this document.
4 Measurands
4.1 General
For obtaining the desired image quality when using a light microscope, the brightness and uniformity of the image play an important role. This holds true for different applications and various types of instruments.
Intentionally, this document is limited to bright field microscopy and detection by means of electronic imaging devices but within this limitation, this document does apply to transmitted or reflected light microscopy and conventional or laser illumination.
4.2 Brightness
The image shall be bright enough to allow the detection of the details of the object under investigation.
Note: This is especially true for microscopic contrasting techniques like phase contrast, differential interference contrast, dark field microscopy, or fluorescence microscopy. Although these contrasting techniques are beyond the scope of this document, the given concepts can be easily extended.
As this document is based on measurement procedures, the image brightness shall be expressed in the corresponding SI units. The photometric unit Illuminance (measured in 1m/m2) shall be used whenever the illumination source covers the visible spectral range (380 nm to 780 nm) continuously, which is usually the case for filament and halogen lamps as well as for phosphor-type white LEDs. The radiometric unit irradiance (measured in W/m2) shall be used for all other illumination sources (like discharge arc lamps, lasers, and single colour LEDs) and are more generally applicable, e.g. to the ultraviolet and infrared spectral range.
4.3 Uniformity
The microscope’s optical system shall achieve a certain degree of image uniformity in order to allow the detection of the details of the object under investigation. A severe drop of the image brightness towards the edge of the image field can result in brightness values that are not sufficient in the above mentioned sense.
Furthermore, spatial variations of the image brightness over the image field cannot always be distinguished from spatial variations of the properties of the object under investigation.
The uniformity of the brightness in the image field is expressed as
Note: Depending on the size of the image field, the objective magnification and the size of the sensor pixels, it might be necessary to apply an adequate averaging method in the computation of the uniformity.
