Editing Face detection

{{Short description|Identification of human faces in images}}
{{about|face detection|face recognition systems|Facial recognition system|human face perception|Face perception}}

[[File:Face detection.jpg|thumb|Automatic face detection with [[OpenCV]]]]

'''Face detection''' is a computer technology being used in a variety of applications that identifies [[face|human faces]] in [[digital image]]s.<ref>{{Cite web | url=https://facedetection.com/ |title = Face Detection: Facial recognition and finding Homepage}}</ref> Face detection also refers to the [[psychological]] process by which humans locate and attend to faces in a visual scene.<ref>{{citation|title=How we detect a face: A survey of psychological evidence|journal=International Journal of Imaging Systems and Technology|volume=13|pages=3–7|year=2003|last1=Lewis|first1=Michael B|last2=Ellis|first2=Hadyn D|s2cid=14976176|doi=10.1002/ima.10040}}</ref>

== Definition and related algorithms ==

Face detection can be regarded as a specific case of [[object-class detection]]. In object-class detection, the task is to find the locations and sizes of all objects in an image that belong to a given class. Examples include upper torsos, pedestrians, and cars.
Face detection simply answers two question, 1. are there any human faces in the collected images or video? 2. where is the face located? 

Face-detection algorithms focus on the detection of frontal human faces. It is analogous to image detection in which the image of a person is matched bit by bit. Image matches with the image stores in database. Any facial feature changes in the database will invalidate the matching process.<ref name="a">{{cite journal |last1=Sheu |first1=Jia-Shing |last2=Hsieh |first2=Tsu-Shien |last3=Shou |first3=Ho-Nien |title=Automatic Generation of Facial Expression Using Triangular Geometric Deformation |journal=Journal of Applied Research and Technology |date=1 December 2014 |volume=12 |issue=6 |pages=1115–1130 |doi=10.1016/S1665-6423(14)71671-2 |language=en |issn=2448-6736|doi-access=free }}</ref>

A reliable face-detection approach based on the [[genetic algorithm]] and the [[Eigenface|eigen-face]]<ref>{{Cite journal |doi = 10.1109/5.628712|title = Face recognition: Eigenface, elastic matching, and neural nets|journal = Proceedings of the IEEE|volume = 85|issue = 9|pages = 1423–1435|year = 1997|last1 = Jun Zhang|last2 = Yong Yan|last3 = Lades|first3 = M.}}</ref> technique:

Firstly, the possible human eye regions are detected by testing all the valley regions in the gray-level image. Then the genetic algorithm is used to generate all the possible face regions which include the eyebrows, the iris, the nostril and the mouth corners.<ref name="a"/>

Each possible face candidate is normalized to reduce both the lighting effect, which is caused by uneven illumination; and the shirring effect, which is due to head movement. The fitness value of each candidate is measured based on its projection on the eigen-faces.  After a number of iterations, all the face candidates with a high fitness value are selected for further verification. At this stage, the face symmetry is measured and the existence of the different facial features is verified for each face candidate.{{CN|date=February 2024}}

== Applications ==
=== Facial motion capture ===
{{Main article|Facial motion capture}}

=== Facial recognition ===
{{Main article|Facial recognition system}}

Face detection is used in [[biometrics]], often as a part of (or together with) a [[facial recognition system]]. It is also used in [[video surveillance]], human computer  interface and image database management.

=== Photography ===
Some recent digital cameras use face detection for autofocus.<ref>{{cite web |url=http://www.dcresource.com/reviews/canon/powershot_s5-review/index.shtml |title=DCRP Review: Canon PowerShot S5 IS |publisher=Dcresource.com |access-date=2011-02-15 |archive-date=2009-02-21 |archive-url=https://web.archive.org/web/20090221223757/http://dcresource.com/reviews/canon/powershot_s5-review/index.shtml |url-status=dead }}</ref> Face detection is also useful for selecting regions of interest in photo slideshows that use a pan-and-scale [[Ken Burns effect]].

Modern appliances also use [[smile detection]] to take a photograph at an appropriate time.

=== Marketing ===
Face detection is gaining the interest of marketers. A webcam can be integrated into a television and detect any face that walks by. The system then calculates the race, gender, and age range of the face. Once the information is collected, a series of advertisements can be played that is specific toward the detected race/gender/age.

An example of such a system is ''OptimEyes'' and is integrated into the  [[Alan Sugar#Amscreen|Amscreen]] digital signage system.<ref>[https://www.theguardian.com/technology/2013/nov/11/tesco-face-detection-sparks-needless-surveillance-panic-facebook-fails-with-teens-do Tesco face detection sparks needless surveillance panic, Facebook fails with teens, doubts over Google+ | Technology | theguardian.com<!-- Bot generated title -->]</ref>
<ref>[https://web.archive.org/web/20190321152321/https://www.amarvelfox.com/ibm-has-to-deal-with-the-privacy-issue-of-facial-recognition.html IBM has to deal with the privacy issue of facial recognition | Technology | amarvelfox.com]</ref>

=== Emotional Inference ===
Face detection can be used as part of a software implementation of [[emotional inference]]. Emotional inference can be used to help people with autism understand the feelings of people around them.<ref>{{Cite journal |last1=Bathelt |first1=Joe |last2=Geurts |first2=Hilde M. |last3=Borsboom |first3=Denny |date=2022-06-01 |title=More than the sum of its parts: Merging network psychometrics and network neuroscience with application in autism |url=https://direct.mit.edu/netn/article/6/2/445/108771/More-than-the-sum-of-its-parts-Merging-network |journal=Network Neuroscience |language=en |volume=6 |issue=2 |pages=445–466 |doi=10.1162/netn_a_00222 |issn=2472-1751 |pmc=9207995 |pmid=35733421}}</ref>

AI-assisted emotion detection in faces has gained significant traction in recent years, employing various models to interpret human emotional states. OpenAI's CLIP model<ref>{{Citation |title=openai/CLIP |date=2024-08-16 |url=https://github.com/openai/CLIP |access-date=2024-08-16 |publisher=OpenAI}}</ref> exemplifies the use of deep learning to associate images and text, facilitating nuanced understanding of emotional content. For instance, combined with a network psychometrics approach, the model has been used to analyze political speeches based on changes in politicians' facial expressions.<ref>{{Cite journal |last1=Tomašević |first1=Aleksandar |last2=Major |first2=Sara |date=2024-08-01 |title=Dynamic exploratory graph analysis of emotions in politics |url=https://advances.in/psychology/10.56296/aip00021/ |journal=Advances.in/Psychology |language=en |volume=2 |pages=e312144 |doi=10.56296/aip00021 |issn=2976-937X}}</ref> Research generally highlights the effectiveness of these technologies, noting that AI can analyze facial expressions (with or without vocal intonations and written language) to infer emotions, although challenges remain in accurately distinguishing between closely related emotions and understanding cultural nuances.<ref>{{Cite journal |last1=Khare |first1=Smith K. |last2=Blanes-Vidal |first2=Victoria |last3=Nadimi |first3=Esmaeil S. |last4=Acharya |first4=U. Rajendra |date=2024-02-01 |title=Emotion recognition and artificial intelligence: A systematic review (2014–2023) and research recommendations |url=https://www.sciencedirect.com/science/article/pii/S1566253523003354 |journal=Information Fusion |volume=102 |pages=102019 |doi=10.1016/j.inffus.2023.102019 |issn=1566-2535}}</ref> 

=== Lip Reading ===
Face detection is essential for the process of language inference from visual cues. [[Automated lip reading]] has applications to help computers determine who is speaking which is needed when security is important.

== See also ==
* [[Computer vision]]
* [[Face ID]]
* [[Pedestrian detection]]
* [[Picasa]]
* [[SceneTap]]
* [[Super recogniser]]
* [[Three-dimensional face recognition]]
* [[TSL color space]]
* [[visage SDK]]
* [[Human sensing]]

== References ==

{{Reflist|30em}}

== External links ==
* [http://homepages.cae.wisc.edu/~ece738/notes/Yang02.pdf Detecting faces in images: a survey]
* [https://astica.ai/vision/facial-recognition/ Face detection and Recognition: Online Demonstration]

{{DEFAULTSORT:Face Detection}}
[[Category:Facial recognition]]
[[Category:Object recognition and categorization]]

[[de:Gesichtserkennung]]