https://wiki.yanding.com/ 2026-09-08T12:09:54+00:00 https://wiki.yanding.com/ https://wiki.yanding.com/lib/tpl/myconfluence/images/favicon.ico text/html 2026-07-24T03:00:19+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.yanding.com/doku.php?id=en:yanding:image_quality_evaluation:image_quality_factors:chromatic_aberration&rev=1784862019&do=diff FIXME This page is not fully translated, yet. Please help completing the translation. (remove this paragraph once the translation is finished) Chromatic Aberration I. What is Chromatic Aberration Chromatic Aberration (CA) refers to the phenomenon where a lens fails to focus all wavelengths of light to the same focal point, resulting in colored fringes (commonly purple, green, or red) along high-contrast edges. Its essence lies in the dispersion of optical materials—the refractive index n v… text/html 2026-07-24T03:00:23+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.yanding.com/doku.php?id=en:yanding:image_quality_evaluation:image_quality_factors:distortion&rev=1784862023&do=diff Distortion I.Definition Distortion is a geometric aberration characterized by the bending of straight lines in the actual scene, which disrupts the geometric similarity between the object and the image, despite not affecting image sharpness. It is determined by the behavior of the chief rays and manifests specifically as an inconsistency in actual lateral magnification across different fields of view. $$D = \frac{\Delta H}{H} \cdot 100$$$\Delta H$$H$$(x_{real}, y_{real})$$r_{\text{real}} = r_{… text/html 2026-07-24T03:00:19+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.yanding.com/doku.php?id=en:yanding:image_quality_evaluation:image_quality_factors:dynamic_range&rev=1784862019&do=diff FIXME This page is not fully translated, yet. Please help completing the translation. (remove this paragraph once the translation is finished) Dynamic Range When shooting against the light, the sky is overexposed and lacks detail, while the foreground subjects are reduced to black $DR_{dB}=20log_{10}(\frac{L_{max}}{L_{min}})$$L_{max}$$L_{min}$ text/html 2026-07-27T11:43:42+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.yanding.com/doku.php?id=en:yanding:image_quality_evaluation:image_quality_factors:field_of_view&rev=1785152622&do=diff Field of View I.Definition The field of view (FOV) describes the extent of the observable scene captured by an imaging system. In photography, the terms field of view (FOV) and angle of view (AOV) are often used interchangeably to refer to the maximum angular extent of a scene observable by a camera. $$\alpha = 2\arctan\left(\frac{d}{2f}\right)$$$d$$f$$d_{h}$$d_{v}$$$HFOV=2arctan\frac{d_{h}}{2f}$$$$VFOV=2arctan\frac{d_{v}}{2f}$$$$DFOV = 2 \arctan\left( \frac{\sqrt{{d_{h}}^2 + {d_{v}}^2}}{2f} \… text/html 2026-07-27T07:57:47+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.yanding.com/doku.php?id=en:yanding:image_quality_evaluation:image_quality_factors:flare&rev=1785139067&do=diff Stray light Stray light is an imaging artifact in which non-imaging rays reaches the image sensor plane through optical paths other than the intended imaging path. It is commonly observed in optical imaging systems under high-irradiance conditions, including backlighting and direct solar illumination. Stray light may lead to reduced image contrast, veiling glare, and various flare-related artifacts. $F$$F$$$F = \frac{S_{black}}{S_{white}} \times 100\%$$$2\text{cd/m}^2$$(5～10)$$\text{Mcd/m}^2$$(… text/html 2026-08-14T07:46:35+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.yanding.com/doku.php?id=en:yanding:image_quality_evaluation:image_quality_factors:mtf_sfr_analysis_and_testing&rev=1786693595&do=diff MTF (Modulation Transfer Function) I.Definition MTF (Modulation Transfer Function) is the modulus of the Optical Transfer Function (OTF), defined as the ratio of the output modulation of the system to the input modulation, describing the contrast transfer capability of an imaging system at different spatial frequencies.$$MTF(f)=\frac{M_{\text{out}}(f)}{M_{\text{in}}(f)}=|OTF(f)|$$$M$$$M=\frac{I_{\max}-I_{\min}}{I_{\max}+I_{\min}}$$$I_{max}$$I_{min}$ text/html 2026-08-20T02:50:53+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.yanding.com/doku.php?id=en:yanding:image_quality_evaluation:image_quality_factors:noise&rev=1787194253&do=diff FIXME This page is not fully translated, yet. Please help completing the translation. (remove this paragraph once the translation is finished) Noise I. Definition Image noise refers to the unintended interference superimposed on the target signal during image acquisition, transmission, or processing. Its external manifestation is the $\sigma_{\text{signal}} = \sqrt{N_{\text{signal}}}$$I_{\text{dark}} \propto A \cdot T^3 e^{-\frac{E_g}{kT}}$$I_{\text{dark}}$$T$$E_g$$k$$A$$\sigma_{\text{dark… text/html 2026-08-14T09:33:39+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.yanding.com/doku.php?id=en:yanding:image_quality_evaluation:image_quality_factors:sharpness&rev=1786700019&do=diff Acutance I. Definition Acutance is an objective physical quantity used to measure image clarity. By contrast, sharpness is the subjective human perception of image clarity; the two are distinct concepts. Early acutance calculations were based on the gradient of an edge profile: the steeper the transition, the higher the value. However, an edge gradient describes only the physical rate of transition and does not account for the fact that images are ultimately perceived by the human visual syst… text/html 2026-07-24T03:00:19+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.yanding.com/doku.php?id=en:yanding:image_quality_evaluation:image_quality_factors:spatial_frequency_units&rev=1784862019&do=diff FIXME This page is not fully translated, yet. Please help completing the translation. (remove this paragraph once the translation is finished) Spatial Frequency Units Units and Applications of Spatial Frequency Conversion Formulas Different units can be converted using parameters such as image height and focal length. The conversion formulas are as follows:$\frac{MTF(C/P)}{\text{pixel pitch}}$$2 \times MTF\left(\frac{LP}{PH}\right)$$2 \times MTF\left(\frac{C}{P}\right) \times PH$$MTF\le… text/html 2026-07-28T07:26:01+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.yanding.com/doku.php?id=en:yanding:image_quality_evaluation:image_quality_factors:uniformity_shading&rev=1785223561&do=diff Shading I.Concept Shading comprises luminance shading and color shading. * Luminance shading refers to the uneven distribution of brightness from the center to the edges of an image (Figure 1). * Color shading refers to the inconsistent color reproduction from the center to the edges of an image (Figure 2).$\theta$$\theta$$\cos^4\theta$ text/html 2026-07-27T12:31:31+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.yanding.com/doku.php?id=en:yanding:image_quality_evaluation:image_quality_factors:white_balance&rev=1785155491&do=diff Auto White Balance I. Color Constancy White balance is based on the phenomenon of color constancy in human vision. Color constancy refers to the ability of the visual system to maintain a stable perception of object colors under illumination with different spectral distributions.