Pixelization

Pixelization (British English, pixelisation) or mosaic processing is any technique used in editing images or video, whereby an image is blurred by displaying part or all of it at a markedly lower . It is primarily used for censorship. The effect is a standard graphics filter, available in all but the most basic bitmap graphics editors. A familiar example of pixelization can be found in a majority of television news and documentary productions, in which vehicle license plates and faces of suspects at crime scenes are routinely obscured to maintain the presumption of innocence, such as how it appears in the television series COPS. This is especially used in Hungary and Slovakia by RTL Klub. Bystanders and others who do not sign release forms are also customarily pixelized. Footage of nudity (including male and female genitals, buttocks, nipples, pubic hair, or areolae) is likewise obscured in some media: before the watershed in many countries, in newspapers or general magazines, or in places in which the public cannot avoid seeing the image (such as on billboards). Drug references, as well as gestures considered obscene (such as the finger) may also be censored in this manner. Pixelization is not usually used for this purpose in films, DVDs, subscription television services, or pornography (except for countries in which the law requires it). When obscene language is censored by an audible bleep, the mouth of the speaker may be pixelized to prevent lip reading, such as in the television series COPS. Graphic injuries and excess blood may also be pixelized. Offense words that are visually visible may also be pixelized. Pixelization may also be used to avoid unintentional product placement, or to hide elements that would date a broadcast, such as date and time stamps on home video submissions. Censorship for such purposes is most common on reality television series. Image:Pixelization mosaic.jpg|Pixelization was used to anonymize this photograph. File:Marshall Webb and Pixelated Classified Document.jpg#filelinks|[[Marshall B.

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Related publications (1)

Crowdsourcing Approach for Evaluation of Privacy Filters in Video Surveillance

Touradj Ebrahimi

Extensive adoption of video surveillance, affecting many aspects of the daily life, alarms the concerned public about the increasing invasion into personal privacy. To address these concerns, many tools have been proposed for protection of personal privacy in image and video. However, little is understood regarding the effectiveness of such tools and especially their impact on the underlying surveillance tasks. In this paper, we propose conducting a subjective evaluation using crowdsourcing to analyze the tradeoff between the preservation of privacy offered by these tools and the intelligibility of activities under video surveillance. As an example, the proposed method is used to compare several commonly employed privacy protection techniques, such as blurring, pixelization, and masking applied to indoor surveillance video. Facebook based crowdsourcing application was specifically developed to gather the subjective evaluation data. Based on more than one hundred participants, the evaluation results demonstrate that the pixelization filter provides the best performance in terms of balance between privacy protection and intelligibility. The results obtained with crowdsourcing application were compared with results of previous work using more conventional subjective tests showing that they are highly correlated.

2012