UL s2017 poster web - Digital Nature Group...1/15, F29 1/20, F22 1/25, F22 1/30, F20 1/60, F14 1/80,...
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Frame 2n-1 Frame 2n High frame rate projection Camera vision Human vision Frame division Source image Frame period Suitable shutter speed/timing Incomplete frame Incomplete frame Time Frame Projection period Protection techniques for digital copies have been discussed over many years from the view- point of data protection. However, content dis- played by general display techniques is not only visible to the human eye but also can be captured by cameras. Therefore, projected content is, at times, secretly taken by malicious small camer- as even when protection techniques for digital copies are adopted. Figure 1: Left: overview of unphotogenic light. We project entire images by switching each divided image at high frame rate. Humans can observe an entire image whereas cameras cannot capture complete photo. Right: theory and effect of the proposed method. The image is divided into multiple parts and projected in turns. We must synchronize camera shutter speed with frame period to capture the entire image correctly. Figure 3: Images from different camera vision. Images are divided into three parts. Projection period (see Figure 1 Right) is 4166 micro- seconds (approximately 240 Hz). Figure 2: Practical stories of the proposed method. (a) Visible watermarks are simple and an effective method. However, it creates bad experiences for visitors. (b) Inspection and secu- rity are other solutions; however, secret photography by small cameras is still feasible. The proposed method aims to prevent secret photography in this situation. (c)–(f) Application examples; top: schematic diagrams, bottom: applications taken by the smartphone. 1/10, F32 1/13, F32 Camera A (Canon EOS Kiss X4 with TAMRON B005 17-50 mm F/2.8, All photos were taken by ISO 100) 1/15, F29 1/20, F22 1/25, F22 1/30, F20 1/60, F14 1/80, F13 1/100, F11 1/125, F10 1/160, F9 1/200, F8 1/250, F7.1 1/320, F6.3 1/400, F5.6 1/500, F5.0 1/10, F22 1/13, F22 Camera B (SONY a7R with SONY SEL55F18Z 55mm F/1.8, All photos were taken by ISO 100) 1/15, F22 1/20, F22 1/25, F22 1/30, F22 1/60, F18 1/80, F16 1/100, F14 1/125, F11 1/160, F11 1/200, F9 1/250, F9 1/320, F8 1/400, F8 1/500, F6.3 1/10, ISO32 1/12, ISO32 Camera C (Apple iPhone 6, with App “ProShot” by Rise Up Games LLC. All photos were taken by F/2.2) Other smartphones and cameras Qua phone (kvy37; Kyocera Corp.) ZenFone 2 (ZE551ML; ASUSTeK Computer Inc.) ZenFone 5 (A500KL; ASUSTeK Computer Inc.) Xperia Z1 (SO-01F, Sony Corp.) DSC-WX110 (Sony corp.) CCD image sensor 1/15, ISO32 1/25, ISO32 1/30, ISO32 1/45, ISO32 1/60, ISO32 1/100, ISO32 1/120, ISO32 1/160, ISO32 1/250, ISO32 1/320, ISO32 1/500, ISO40 1/1000, ISO80 1/2000, ISO160 1/4400, ISO400 1/590, F2.2, ISO50 1/2298, F2, ISO400 1/445, F2, ISO50 1/640, F2, ISO50 1/200, F7.1, ISO125 (a) Vidible watermarks, protection marks (b) Inspection and security CONFIDENTIAL Baggage Check COPYRIGHT NO PHOTOS Bad Experience Image Visitor Pocket Pen-shaped small camera in visitor’s pocket Confiscated Camera Secret Camera Visitor’s bag EXIT $10 Photo taken in roller coaster Photo by Ted Murphy (CC BY 2.0) Result Projector Sushi Projector Projector Protected object Showcase Painting Result Result Visitors (c) (d) (e) (f) We exploit the difference between the human vision system and the camera vision system. Notably, humans cannot recognize the high- speed changes of light. We were inspired by previous work that used these properties to show on-screen invisible markers. There are sev- eral studies that aim to present imperceptible on-screen markers using high-speed projection between the afterimage effect of human eyes and shutter speeds of digital cameras. From an- other point of view, these techniques show spe- cific content only to the human eye while show- ing different content to a camera. Thus, we can project images that can be seen by human eyes whereas cameras only capture an incom- plete frame as illustrated in Figure 1. Therefore, this means the projected light is unphotogenic. The main purpose of this method is to discover pro- tection techniques to prevent secret photogra- phy. For example, it can be applied to secret pages in a presentation. Speakers then do not need to caution the audience members about taking photos. As another example, our system can be used in theme parks as shown in Figure 2 (c). There is a system that takes a picture of passengers in the middle of an attraction such as a roller coaster in theme parks. Pictures are previewed on a screen near the exit, and a passenger has the option to purchase the picture. However, a passenger can also take photos of the screen with a smartphone. By using the proposed method, these photos are prevented. In addition, if the shape is divided into the silhouette of a character, people will be able to enjoy theme parks even more. The proposed system also can be used as a lighting system. For example, the system can be installed in an art gallery as a spotlight, as shown in Figure 2 (d). It is worth noting that photos with DSLR cameras may still be taken. Therefore, the next example is a situation in which a visitor cannot use a DSLR camera, as shown in Figure 2 (e). Because the showcase surface has reflections, it is difficult to shoot with a camera with a large lens such as that of a DSLR camera. In this case, a small camera such as a smartphone will be used; however, the proposed method prevents this when installed as a spotlight. As another example, the proposed system can be used in restaurants. If a restaurant chef dislikes the photogra- phy of food by smartphones, the proposed system can be used as lighting. Because the customers cannot take photos with their smartphones as shown in Figure 2 (f), they can instead concentrate on eating the food. Unphotogenic Light: High-Speed Projection Method to Prevent Secret Photography by Small Cameras Problem Implementation Our Approach Protection of screen content Protective illumination Ippei Suzuki* Yoichi Ochiai** University of Tsukuba http://digitalnature.slis.tsukuba.ac.jp/2017/07/unphotogenic-light *[email protected] **[email protected] We use a high-speed programmable projector (DLPa Light Crafter 4500, Texas Instruments Inc.) that projects divided images with high speeds. If we attempt to capture the entire image with the camera, we must match the projection period of the system and exposure period of the camera, as shown in Figure 1. Applications Evaluation We evaluate our system with the vision of a camera, as shown in Figure 3. First, we used DSLR cameras to evaluate the shutter speed threshold in which the proposed method is most effective. The results are shown in Figure 3 (Camera A and Camera B). When the shutter speed is faster than 1/60, the effect of our method is noticeable in the picture. Next, a smartphone (iPhone 6, Apple Inc.) was used to consider the scene of practical secret pho- tography. We used a camera application that can control the shutter and ISO speeds as shown in Figure 3 (Camera C). Please note that the f-stop of the smartphone is not controllable. If the bright- ness of the screen is sufficiently high, the camera speeds up the shutter speed to avoid blowing out highlights. Because small cameras tend to have this limitation, the proposed system is effective to prevent secret photography by small cameras.
Transcript of UL s2017 poster web - Digital Nature Group...1/15, F29 1/20, F22 1/25, F22 1/30, F20 1/60, F14 1/80,...
Frame 2n-1
Frame 2n
High frame rate projection Camera vision
Human vision
Frame division
Source image Frame period
Suitable shutter speed/timingIncomplete frame Incomplete frame
Time
Frame
Projection period
Protection techniques for digital copies have been discussed over many years from the view-point of data protection. However, content dis-played by general display techniques is not only visible to the human eye but also can be captured by cameras. Therefore, projected content is, at times, secretly taken by malicious small camer-as even when protection techniques for digital copies are adopted.
Figure 1: Left: overview of unphotogenic light. We project entire images by switching each divided image at high frame rate. Humans can observe an entire image whereas cameras cannot capture complete photo. Right: theory and effect of the proposed method. The image is divided into multiple parts and projected in turns. We must synchronize camera shutter speed with frame period to capture the entire image correctly.
Figure 3: Images from different camera vision. Images are divided into three parts. Projection period (see Figure 1 Right) is 4166 micro-seconds (approximately 240 Hz).
Figure 2: Practical stories of the proposed method. (a) Visible watermarks are simple and an effective method. However, it creates bad experiences for visitors. (b) Inspection and secu- rity are other solutions; however, secret photography by small cameras is still feasible. The proposed method aims to prevent secret photography in this situation. (c)–(f) Application examples; top: schematic diagrams, bottom: applications taken by the smartphone.
1/10, F32 1/13, F32
Camera A (Canon EOS Kiss X4 with TAMRON B005 17-50 mm F/2.8, All photos were taken by ISO 100)
1/15, F29 1/20, F22 1/25, F22 1/30, F20 1/60, F14 1/80, F13
1/100, F11 1/125, F10 1/160, F9 1/200, F8 1/250, F7.1 1/320, F6.3 1/400, F5.6 1/500, F5.0
1/10, F22 1/13, F22
Camera B (SONY a7R with SONY SEL55F18Z 55mm F/1.8, All photos were taken by ISO 100)
1/15, F22 1/20, F22 1/25, F22 1/30, F22 1/60, F18 1/80, F16
1/100, F14 1/125, F11 1/160, F11 1/200, F9 1/250, F9 1/320, F8 1/400, F8 1/500, F6.3
1/10, ISO32 1/12, ISO32
Camera C (Apple iPhone 6, with App “ProShot” by Rise Up Games LLC. All photos were taken by F/2.2)
Other smartphones and cameras
Qua phone (kvy37; Kyocera Corp.)ZenFone 2
(ZE551ML; ASUSTeK Computer Inc.)ZenFone 5
(A500KL; ASUSTeK Computer Inc.) Xperia Z1 (SO-01F, Sony Corp.)DSC-WX110 (Sony corp.)
CCD image sensor
1/15, ISO32 1/25, ISO32 1/30, ISO32 1/45, ISO32 1/60, ISO32 1/100, ISO32
1/120, ISO32 1/160, ISO32 1/250, ISO32 1/320, ISO32 1/500, ISO40 1/1000, ISO80 1/2000, ISO160 1/4400, ISO400
1/590, F2.2, ISO50 1/2298, F2, ISO400 1/445, F2, ISO50 1/640, F2, ISO50 1/200, F7.1, ISO125
(a) Vidible watermarks, protection marks (b) Inspection and security
CONFIDENTIAL
Baggage Check
COPYRIGHT
NO PHOTOS
Bad Experience
Image
Visitor
Pen-shaped smallcamera in visitor’s
ConfiscatedCamera
Secret Camera
Visitor’s bag
EXIT
$10
Photo taken in roller coaster
Photo by Ted Murphy (CC BY 2.0)
Result
Projector
Sushi
Projector
Projector
Protected object
Showcase
Painting
Result Result
Visitors
(c) (d) (e) (f)
We exploit the difference between the human vision system and the camera vision system. Notably, humans cannot recognize the high- speed changes of light. We were inspired by previous work that used these properties to show on-screen invisible markers. There are sev-eral studies that aim to present imperceptible on-screen markers using high-speed projection between the afterimage effect of human eyes and shutter speeds of digital cameras. From an-other point of view, these techniques show spe-cific content only to the human eye while show-ing different content to a camera. Thus, we can project images that can be seen by human eyes whereas cameras only capture an incom-plete frame as illustrated in Figure 1. Therefore, this means the projected light is unphotogenic.
The main purpose of this method is to discover pro-tection techniques to prevent secret photogra-phy. For example, it can be applied to secret pages in a presentation. Speakers then do not need to caution the audience members about taking photos.
As another example, our system can be used in theme parks as shown in Figure 2 (c). There is a system that takes a picture of passengers in the middle of an attraction such as a roller coaster in theme parks. Pictures are previewed on a screen near the exit, and a passenger has the option to purchase the picture. However, a passenger can also take photos of the screen with a smartphone. By using the proposed method, these photos are prevented. In addition, if the shape is divided into the silhouette of a character, people will be able to enjoy theme parks even more.
The proposed system also can be used as a lighting system. For example, the system can be installed in an art gallery as a spotlight, as shown in Figure 2 (d).
It is worth noting that photos with DSLR cameras may still be taken. Therefore, the next example is a situation in which a visitor cannot use a DSLR camera, as shown in Figure 2 (e). Because the showcase surface has reflections, it is difficult to shoot with a camera with a large lens such as that
of a DSLR camera. In this case, a small camera such as a smartphone will be used; however, the proposed method prevents this when installed as a spotlight.
As another example, the proposed system can be used in restaurants. If a restaurant chef dislikes the photogra-phy of food by smartphones, the proposed system can be used as lighting. Because the customers cannot take photos with their smartphones as shown in Figure 2 (f), they can instead concentrate on eating the food.
Unphotogenic Light:High-Speed Projection Method to Prevent Secret Photography by Small Cameras
Problem Implementation
Our Approach
Protection of screen content
Protective illumination
Ippei Suzuki* Yoichi Ochiai** University of Tsukubahttp://digitalnature.slis.tsukuba.ac.jp/2017/07/unphotogenic-light
*[email protected]**[email protected]
We use a high-speed programmable projector (DLPa Light Crafter 4500, Texas Instruments Inc.) that projects divided images with high speeds. If we attempt to capture the entire image with the camera, we must match the projection period of the system and exposure period of the camera, as shown in Figure 1.
Applications
EvaluationWe evaluate our system with the vision of a camera, as shown in Figure 3. First, we used DSLR cameras to evaluate the shutter speed threshold in which the proposed method is most effective. The results are shown in Figure 3 (Camera A and Camera B). When the shutter speed is faster than 1/60, the effect of our method is noticeable in the picture.
Next, a smartphone (iPhone 6, Apple Inc.) was used to consider the scene of practical secret pho-tography. We used a camera application that can control the shutter and ISO speeds as shown in Figure 3 (Camera C). Please note that the f-stop of the smartphone is not controllable. If the bright-ness of the screen is sufficiently high, the camera speeds up the shutter speed to avoid blowing out highlights. Because small cameras tend to have this limitation, the proposed system is effective to prevent secret photography by small cameras.
