mathematics

Transfer functions in imaging

Transfer functions in imaging is a mathematics topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Transfer functions in imaging rather than just read about it. In short: Images and videos use specific transfer functions to describe the relationship between electrical signal, scene light and displayed light. Definition The opto-electronic transfer function (OETF) is the transfer function having the scene light as input and converting into the picture or video signal as output.

Key takeaways

Transfer functions in imaging belongs to mathematics; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Transfer functions in imaging to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Transfer functions in imaging from memory before moving on to harder problems.

Reference excerpt

Images and videos use specific transfer functions to describe the relationship between electrical signal, scene light and displayed light.

Definition The opto-electronic transfer function (OETF) is the transfer function having the scene light as input and converting into the picture or video signal as output. This is typically done within a camera. The electro-optical transfer function (EOTF) is the transfer function having the picture or video signal as input and converting it into the linear light output of the display. This is done within a display device. The opto-optical transfer function (OOTF) is the transfer function having the scene light as input and the displayed light as output. The OOTF is the composition of the OETF and the EOTF and is usually non-linear.

List of transfer functions

Linear Raw formats Some OETF and EOTF have an initial linear portion followed by a non-linear part (e.g. sRGB and Rec.709).

Gamma Rec. 601, Rec. 709 and Rec. 2020: The ITU-R recommendations BT.601, BT.709 and BT.2020 describe the reference OETF of respectively SD-TV, HD-TV and UHD-TV. They are identical OETF based on a gamma curve and used for SDR-TV. BT.1886: The ITU-R Recommendation BT.1886 is the reference EOTF of Standard Dynamic Range TV (SDR). sRGB: sRGB defines a transfer function based on a gamma curve and used for monitors, printers and the Web. sRGB is standardized as IEC 61966-2-1:1999

Logarithmic S-Log: Developed by Sony for digital cameras in order to increase captured dynamic range Canon Log: Developed by Canon for digital cameras in order to increase captured dynamic range Arri Log C: Developed by Arri for digital cameras in order to increase captured dynamic range

HDR These transfer functions have been developed to allow HDR display:

Perceptual quantizer: PQ is a transfer function developed by Dolby for HDR and allowing a luminance level of up to 10,000 cd/m2. It is standardized in Rec. 2100 and also as SMPTE ST 2084. Hybrid log–gamma: HLG is a transfer function developed by NHK and BBC for HDR and offering some backward compatibility on SDR displays. HLG is a hybrid transfer function in which the lower half of the signal values use a gamma curve and the upper half of the signal values use a logarithmic curve. It is standardized in Rec. 2100.

References

Worked examples

Example 1 — a first encounter with Transfer functions in imaging

Start with the simplest possible case. Write down what Transfer functions in imaging claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In mathematics, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Transfer functions in imaging before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Transfer functions in imaging ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Transfer functions in imaging

In research: Transfer functions in imaging appears in mathematics research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Transfer functions in imaging in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Transfer functions in imaging is common in secondary-school and first-year university syllabi. It links to neighbouring topics Imaging, Transfer functions, Video, so understanding it makes those chapters shorter.
In everyday life: Look for Transfer functions in imaging outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Transfer functions in imaging in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Transfer functions in imaging means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Transfer functions in imaging out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Transfer functions in imaging in simple terms?

Images and videos use specific transfer functions to describe the relationship between electrical signal, scene light and displayed light. Definition The opto-electronic transfer function (OETF) is the transfer function having the scene light as input and converting into the picture or video signal…

Why does Transfer functions in imaging matter?

Because it connects several mathematics ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Transfer functions in imaging?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Transfer functions in imaging.