Accommodation responses to horizontal-parallax-only super multiview display
Nakamura, Junya
Tanaka, Kosuke
Takaki, Yasuhiro
Super multi-view (SMV) displays have been developed to solve the vergence-accommodation conflict that causes visual fatigue with conventional three-dimensional (3D) displays. An ideal SMV display should generate dense viewpoints in both the horizontal and vertical directions. However, the SMV displays developed so far generate dense viewpoints only in the horizontal direction because of the system complexity required for full-parallax systems. Therefore, the accommodation responses to SMV displays were measured mostly for 3D images that contain distinctive vertical edges. In this study, we investigated the influences of the edge properties contained in 3D images upon the accommodation responses evoked by horizontal-parallax-only (HPO) SMV displays. We used the recently developed reduced-view SMV display, whose interval of viewpoints was 2.6 mm, for the accommodation measurements. Two test images were used: a “Maltese cross”, which contains several sharp edges, and a standard test image of “Lenna”, which contains various types of edges. We found that the HPO–SMV display still evoked the accommodation responses when “Lenna” was displayed. There were two types of accommodation responses for “Lenna”; the amounts of the evoked accommodation were smaller than or similar to those for the “Maltese cross”, depending on where the viewers gazed. 
 Thank you Mr. Chairman. My name is Jumiya Nakamura from Tokyo University of Agriculture and Technology. The title of my talk is Accommodation Responses to Horizontal Parks Only Supermultiview Display. So first I want to explain about the Brazilian Accommodation Compact. In the real scene both versions and accommodation work correctly on the real object. On the other hand the accommodation does not work appropriately to the 3D image generated by conventional 3D displays because the eye focus on the display screen instead of 3D images while versions work correctly. The conflict between versions and accommodation causes visual fatigue while viewing 3D images. So it is a critical issue in conventional 3D displays. Supermultiview display is the 3D display proposed to solve the versions accommodation conflict. The supermultiview display generates a large number of viewpoints at intervals smaller than the pupil diameter. In the other hand the SMV display allows two or more rays passing through a point in 3D space to enter the pupil simultaneously because the eye might be able to focus on that point. So the supermultiview display is free from the version accommodation conflict. An ideal SMV display should generate dense viewpoints in both horizontal and vertical directions. However the SMV displays developed so far are the horizontal parts only type because of system complexities. Therefore the accommodation measurements were performed mostly for using test images containing distinctive vertical edge. So in this study we investigate the influence of edge properties contained in 3D images upon the accommodation responses evoked by HP or SMV display. In the measurement we use the reduced view SMV display because the reduced view SMV display can generate viewpoints at a smaller interval than the previous SMV displays. The reduced view SMV display has been proposed to reduce resolution required for flat panel display. To reduce the number of views reduced view SMV display generates dense viewpoints only around the viewer's left and right eyes. Because the reduced view SMV display consists of flat panel display and lenticular lens, 3D images with less distortion and less blur can be produced. The specification is shown here. The interval viewpoints was 2.6 millimeters. The number of viewpoints was 8 plus 8 for each eye. Observation distance was 350 millimeters. The screen size was 2.57 inches and 3D resolution was 256 by 192. And we used two types of test images to investigate the influence of the edge properties contained in 3D images. Left figure shows the multi-cloth which contains sharp edges in horizontal, vertical and diagonal directions. And right figure shows Lena which is a well-known test image containing various edges in various directions. This slide explains the measurement conditions. To investigate the increase in the range of accommodation responses, we changed the interval viewpoints among 2.6, 5.3 and 7.9 millimeters by displaying identical products images at 2 or 3 adjacent viewpoints. The viewing angle of test images was 2.8 degrees by 2.8 degrees. Observation distance was 350 millimeters. The distance to test image from the display screen was from 105 millimeters behind the screen to 75 millimeters in front of the screen. The number of trial was 3. And in each trial, the responses were measured in 2 seconds. And the responses within 2 seconds without blinking were averaged. And the number of subjects was 5. We used order estimator grand cycle FR5500S. And for comparison, we measured the accommodation responses to real target. So this slide shows the typical results obtained for multi-cloth of subject HN. This figure shows the accommodation responses to real object. And this figure shows the accommodation responses to 3D images for viewing interval of 2.6, 5.3 and 7.9 millimeters. In each figure, horizontal axis shows the distance to test target. And vertical axis shows the measured accommodation responses. Most values are represented in the after unit, which is reciprocal of length in meters. And these diodes show the average pupil diameter in the trials. And in this study, in this study, the range of accommodation responses obtained for 3D images to be obtained for all distances is defined as DOF. Usually, the depth of field DOF is depth range in which an object can be imaged without blur. And from these results, the DOF obtained for viewing interval of 2.6 millimeters was greater than the DOF obtained for other view interval. The DOF might increase because the extent of rates at the pupil was smaller than the pupil diameter when view interval was 2.6 millimeters. And because accommodation responses are different between subjects, so we compare the responses to real object to responses to 3D images. Horizontal axis shows the accommodation responses to real object. And the vertical axis shows the responses to 3D images. When 3D image was displayed in DOF range, the accommodation responses to 3D image was approximately equal to the responses to real object. On the other hand, the 3D image was displayed outside the DOF, the accommodation responses became saturated. And these figures show the accommodation responses to Lena obtained for same subject, HN. The results were very similar to those for multiple scrolls. When the view interval was 2.6 millimeters, the DOF was greater than the DOF obtained for other view intervals. In measurement results, we found that there are two tendencies of accommodation responses to Lena when view interval was 2.6 millimeters. In this slide, we show the results for the first group. For three subjects, the ranges of accommodation responses for Lena were similar to those for the multiple scrolls. And these figures show the results for the other group. For these two subjects, the range of accommodation responses for Lena were smaller than those for the multiple scrolls. These subjects might pay attention to the types of edges other than the particular one contained in Lena. So from the results, the HP or assembly display still evoked the accommodation responses even when Lena, that contains various types of edges, was displayed. So to investigate the blur in the retinal images according to the accommodation responses, we captured retinal images using a camera. This slide shows the evaluation method. The camera focus was changed to three different positions such as display screen, 3D image, and eye accommodation positions. This figure shows the typical accommodation responses to real images. This range is the DOF to obtain the four 3D images. From the accommodation responses to real target, we can estimate focus positions of subjects eyes. And we use these estimated focus positions as eye accommodation positions. The other conditions are shown in this table. The interval view point was 2.6, 5.3, and 7.9 millimeters. The distance between the camera and the screen was 350 millimeters. And the distance to test images from the screen was plus and minus 45 millimeters. We used a cool CCD camera to capture the images. These photographs are the retinal images of multi-scrub, displayed at 45 millimeters in front of the screen. These figures show these photographs are the images when the view interval was 2.6 millimeters. These photographs are retinal images when the view interval was 5.3 millimeters. And these figures were captured when the view interval was 7.9 millimeters. And these figures are retinal images captured by camera focusing on 3D image. These images are retinal images captured by camera focusing on eye accommodation positions. And these figures are the retinal images captured by camera focusing on the display screen. So we first consider the case where the view interval was 2.6 millimeters. When the camera focused on the display screen, twin images was obtained. On the other hand, when the camera was focused on eye accommodation positions, single image was obtained. Therefore, the subject's eyes might focus on eye accommodation positions. And next, we consider the case where the view intervals was 7.9 millimeters. When the camera focused on the display screen, single image was obtained. And when the camera was focused on eye accommodation distance, there apparently blur was observed. So the viewers might have paid attention. The viewers might focus on the display screen. And these photographs are the retinal images. So, the camera is close, displayed at 45 millimeters behind the screen. The same results, we obtained the same results. When the camera focused on the screen, twin image, and the camera focused on the eye accommodation position, single image. And also, we obtained similar results for Lena. When the camera focused on the screen, the twin image was obtained. On the other hand, camera focused on eye accommodation position, single image. So, viewers eye might focus on the eye accommodation positions. And this is the result for Lena when the 3D image was displayed behind the screen. And we also obtained similar results. So I conclude my talk. The accommodation responses to the HP or SMV display measured. And we found that the HP or SMV display still evoked the accommodation responses, even when the standard test image, Lena, that contains various types of edge was displayed. And the amount of evoked accommodation for Lena were smaller than or similar to those for the test image containing obvious vertical edge, depending on where the subject gets. The blur in retinal image was investigated by capturing retinal image using a camera. Thank you for your attention. Okay. Just to clarify, when you said that you're capturing retinal images using a camera, you're simulating the eye using a camera. So your camera has the same focal distance as your eye would have? Yes, I use a camera. And the aperture diameter of the camera was same to the aperture diameter of subjects. The pupil of the subject's eyes, same pupil in the camera, same focus distance. Same diameter. I guess follow up the previous question. And I think I just want to make sure that you confirm that the focal length of the camera is the same as the human vision system, because even though the pupil diameter is the same, but the depth of field of your camera is not necessary the same as the human eye. You mean the DOF? Yes, the focal length is very critical in this case, not just the pupil diameter. I guess I just want to make sure we understand the focal length is also matched. What is the focal length of the camera? The focal length of the camera I use was 60 millimeters. I think that's a really important result. That's really encouraging for volumetric displays, multifocal displays, that so few viewpoints seem to stimulate accommodations. That's a really important result. And it's great. But I have one kind of technical question about the way you measure accommodation. Accommodation can be voluntary or involuntary in humans. And the way we often tell whether it's voluntary or involuntary is by the dynamics, how fast it occurs, and whether it occurs in the right direction. So my question is, what do you know about the time variation of the accommodation response that you observed? Was it fast? Was it slow? Did it sometimes go the wrong direction and come back? That would give us some way to assess the degree to which it was voluntary versus involuntary. I'm sorry, I don't understand your question. Let's talk about it later. But it's a really nice result. Thank you. So you mean time axis. So you mean we should evaluate the accommodation in time axis. You mean so? Yeah. When you're trying to, so you can, through voluntary effort, through your will, you can make an accommodation that's not natural. You can say, oh, that looks blurry. I'm going to try something and then sharpen it. But when you do that, it's slow and it often goes the wrong direction first. And so you can use the time course of your accommodation responses to help us decide whether this is a natural involuntary response that you measured or whether it's an unnatural voluntary response. I'll talk to you about it during coffee. I can sort of draw it out for you. Okay. Thank you. But nice paper. Okay. We are running out of time. So thank you, speaker. Thank you very much. Thank you.
 Thank you Mr. Chairman. My name is Jumiya Nakamura from Tokyo University of Agriculture  and Technology. The title of my talk is Accommodation Responses to Horizontal Parks Only Supermultiview  Display. So first I want to explain about the Brazilian  Accommodation Compact. In the real scene both versions and accommodation work correctly  on the real object. On the other hand the accommodation does not work appropriately to the 3D image  generated by conventional 3D displays because the eye focus on the display screen instead  of 3D images while versions work correctly. The conflict between versions and accommodation  causes visual fatigue while viewing 3D images. So it is a critical issue in conventional  3D displays. Supermultiview display is the 3D display  proposed to solve the versions accommodation conflict. The supermultiview display generates  a large number of viewpoints at intervals smaller than the pupil diameter.  In the other hand the SMV display allows two or more rays passing through a point in 3D  space to enter the pupil simultaneously because the eye might be able to focus on that point.  So the supermultiview display is free from the version accommodation conflict.  An ideal SMV display should generate dense viewpoints in both horizontal and vertical  directions. However the SMV displays developed so far are the horizontal parts only type  because of system complexities. Therefore the accommodation measurements were performed  mostly for using test images containing distinctive vertical edge.  So in this study we investigate the influence of edge properties contained in 3D images  upon the accommodation responses evoked by HP or SMV display.  In the measurement we use the reduced view SMV display because the reduced view SMV display  can generate viewpoints at a smaller interval than the previous SMV displays.  The reduced view SMV display has been proposed to reduce resolution required for flat panel  display. To reduce the number of views reduced view  SMV display generates dense viewpoints only around the viewer's left and right eyes.  Because the reduced view SMV display consists of flat panel display and lenticular lens,  3D images with less distortion and less blur can be produced.  The specification is shown here. The interval viewpoints was 2.6 millimeters.  The number of viewpoints was 8 plus 8 for each eye. Observation distance was 350 millimeters.  The screen size was 2.57 inches and 3D resolution was 256 by 192.  And we used two types of test images to investigate the influence of the edge properties contained  in 3D images. Left figure shows the multi-cloth which contains  sharp edges in horizontal, vertical and diagonal directions.  And right figure shows Lena which is a well-known test image containing various edges in various  directions. This slide explains the measurement conditions.  To investigate the increase in the range of accommodation responses, we changed the interval  viewpoints among 2.6, 5.3 and 7.9 millimeters by displaying identical products images at  2 or 3 adjacent viewpoints. The viewing angle of test images was 2.8  degrees by 2.8 degrees. Observation distance was 350 millimeters.  The distance to test image from the display screen was from 105 millimeters behind the  screen to 75 millimeters in front of the screen.  The number of trial was 3. And in each trial, the responses were measured  in 2 seconds. And the responses within 2 seconds without blinking were averaged.  And the number of subjects was 5. We used order estimator grand cycle FR5500S.  And for comparison, we measured the accommodation responses to real target.  So this slide shows the typical results obtained for multi-cloth of subject HN.  This figure shows the accommodation responses to real object.  And this figure shows the accommodation responses to 3D images for viewing interval of 2.6,  5.3 and 7.9 millimeters. In each figure, horizontal axis shows the  distance to test target. And vertical axis shows the measured accommodation  responses. Most values are represented in the after  unit, which is reciprocal of length in meters. And these diodes show the average pupil diameter  in the trials. And in this study, in this study, the range  of accommodation responses obtained for 3D images to be obtained for all distances is  defined as DOF. Usually, the depth of field DOF is depth  range in which an object can be imaged without blur.  And from these results, the DOF obtained for viewing interval of 2.6 millimeters was greater  than the DOF obtained for other view interval. The DOF might increase because the extent  of rates at the pupil was smaller than the pupil diameter when view interval was 2.6  millimeters. And because accommodation responses are different  between subjects, so we compare the responses to real object to responses to 3D images.  Horizontal axis shows the accommodation responses to real object.  And the vertical axis shows the responses to 3D images.  When 3D image was displayed in DOF range, the accommodation responses to 3D image was approximately  equal to the responses to real object. On the other hand, the 3D image was displayed  outside the DOF, the accommodation responses became saturated.  And these figures show the accommodation responses to Lena obtained for same subject, HN.  The results were very similar to those for multiple scrolls. When the view interval was  2.6 millimeters, the DOF was greater than the DOF obtained for other view intervals.  In measurement results, we found that there are two tendencies of accommodation responses  to Lena when view interval was 2.6 millimeters. In this slide, we show the results for the  first group. For three subjects, the ranges of accommodation  responses for Lena were similar to those for the multiple scrolls.  And these figures show the results for the other group. For these two subjects, the range  of accommodation responses for Lena were smaller than those for the multiple scrolls.  These subjects might pay attention to the types of edges other than the particular one  contained in Lena. So from the results, the HP or assembly display  still evoked the accommodation responses even when Lena, that contains various types of  edges, was displayed. So to investigate the blur in the retinal  images according to the accommodation responses, we captured retinal images using a camera.  This slide shows the evaluation method. The camera focus was changed to three different  positions such as display screen, 3D image, and eye accommodation positions.  This figure shows the typical accommodation responses to real images.  This range is the DOF to obtain the four 3D images.  From the accommodation responses to real target, we can estimate focus positions of subjects  eyes. And we use these estimated focus positions as eye accommodation positions.  The other conditions are shown in this table. The interval view point was 2.6, 5.3, and  7.9 millimeters. The distance between the camera and the screen  was 350 millimeters. And the distance to test images from the screen  was plus and minus 45 millimeters. We used a cool CCD camera to capture the images.  These photographs are the retinal images of multi-scrub, displayed at 45 millimeters  in front of the screen. These figures show these photographs are the images when the  view interval was 2.6 millimeters. These photographs are retinal images when the view interval was  5.3 millimeters. And these figures were captured when the view  interval was 7.9 millimeters. And these figures are retinal images captured  by camera focusing on 3D image. These images are retinal images captured by camera focusing  on eye accommodation positions. And these figures are the retinal images captured by  camera focusing on the display screen. So we first consider the case where the view  interval was 2.6 millimeters. When the camera focused on the display screen,  twin images was obtained. On the other hand, when the camera was focused on eye accommodation  positions, single image was obtained. Therefore, the subject's eyes might focus on eye accommodation  positions. And next, we consider the case where the view intervals was 7.9 millimeters.  When the camera focused on the display screen, single image was obtained. And when the camera  was focused on eye accommodation distance, there apparently blur was observed. So the  viewers might have paid attention. The viewers might focus on the display screen.  And these photographs are the retinal images. So, the camera is close, displayed at 45 millimeters  behind the screen. The same results, we obtained the same results.  When the camera focused on the screen, twin image, and the camera focused on the eye accommodation  position, single image. And also, we obtained similar results for Lena.  When the camera focused on the screen, the twin image was obtained. On the other hand,  camera focused on eye accommodation position, single image. So, viewers eye might focus on  the eye accommodation positions. And this is the result for Lena when the 3D image was  displayed behind the screen. And we also obtained similar results.  So I conclude my talk. The accommodation responses to the HP or SMV display measured.  And we found that the HP or SMV display still evoked the accommodation responses, even when  the standard test image, Lena, that contains various types of edge was displayed.  And the amount of evoked accommodation for Lena were smaller than or similar to those  for the test image containing obvious vertical edge, depending on where the subject gets.  The blur in retinal image was investigated by capturing retinal image using a camera.  Thank you for your attention.  Okay.  Just to clarify, when you said that you're capturing retinal images using a camera,  you're simulating the eye using a camera. So your camera has the same focal distance  as your eye would have?  Yes, I use a camera. And the aperture diameter of the camera was same to the aperture diameter  of subjects.  The pupil of the subject's eyes, same pupil in the camera, same focus distance.  Same diameter.  I guess follow up the previous question. And I think I just want to make sure that you  confirm that the focal length of the camera is the same as the human vision system, because  even though the pupil diameter is the same, but the depth of field of your camera is not  necessary the same as the human eye.  You mean the DOF?  Yes, the focal length is very critical in this case, not just the pupil diameter. I  guess I just want to make sure we understand the focal length is also matched.  What is the focal length of the camera?  The focal length of the camera I use was 60 millimeters.  I think that's a really important result. That's really encouraging for volumetric displays,  multifocal displays, that so few viewpoints seem to stimulate accommodations. That's a  really important result. And it's great. But I have one kind of technical question about  the way you measure accommodation. Accommodation can be voluntary or involuntary in humans.  And the way we often tell whether it's voluntary or involuntary is by the dynamics, how fast  it occurs, and whether it occurs in the right direction.  So my question is, what do you know about the time variation of the accommodation response  that you observed? Was it fast? Was it slow? Did it sometimes go the wrong direction and  come back? That would give us some way to assess the degree to which it was voluntary  versus involuntary.  I'm sorry, I don't understand your question.  Let's talk about it later. But it's a really nice result. Thank you.  So you mean time axis. So you mean we should evaluate the accommodation in time axis. You  mean so? Yeah. When you're trying to, so you can, through voluntary effort, through your  will, you can make an accommodation that's not natural. You can say, oh, that looks blurry.  I'm going to try something and then sharpen it. But when you do that, it's slow and it  often goes the wrong direction first. And so you can use the time course of your accommodation  responses to help us decide whether this is a natural involuntary response that you measured  or whether it's an unnatural voluntary response. I'll talk to you about it during coffee. I  can sort of draw it out for you. Okay. Thank you.  But nice paper. Okay. We are running out of time. So thank you, speaker.  Thank you very much.  Thank you.
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Thank you Mr. Chairman. My name is Jumiya Nakamura from Tokyo University of Agriculture and Technology. The title of my talk is Accommodation Responses to Horizontal Parks Only Supermultiview Display. So first I want to explain about the Brazilian Accommodation Compact. In the real scene both versions and accommodation work correctly on the real object. On the other hand the accommodation does not work appropriately to the 3D image generated by conventional 3D displays because the eye focus on the display screen instead of 3D images while versions work correctly. The conflict between versions and accommodation causes visual fatigue while viewing 3D images. So it is a critical issue in conventional 3D displays. Supermultiview display is the 3D display proposed to solve the versions accommodation conflict. The supermultiview display generates a large number of viewpoints at intervals smaller than the pupil diameter. In the other hand the SMV display allows two or more rays passing through a point in 3D space to enter the pupil simultaneously because the eye might be able to focus on that point. So the supermultiview display is free from the version accommodation conflict. An ideal SMV display should generate dense viewpoints in both horizontal and vertical directions. However the SMV displays developed so far are the horizontal parts only type because of system complexities. Therefore the accommodation measurements were performed mostly for using test images containing distinctive vertical edge. So in this study we investigate the influence of edge properties contained in 3D images upon the accommodation responses evoked by HP or SMV display. In the measurement we use the reduced view SMV display because the reduced view SMV display can generate viewpoints at a smaller interval than the previous SMV displays. The reduced view SMV display has been proposed to reduce resolution required for flat panel display. To reduce the number of views reduced view SMV display generates dense viewpoints only around the viewer's left and right eyes. Because the reduced view SMV display consists of flat panel display and lenticular lens, 3D images with less distortion and less blur can be produced. The specification is shown here. The interval viewpoints was 2.6 millimeters. The number of viewpoints was 8 plus 8 for each eye. Observation distance was 350 millimeters. The screen size was 2.57 inches and 3D resolution was 256 by 192. And we used two types of test images to investigate the influence of the edge properties contained in 3D images. Left figure shows the multi-cloth which contains sharp edges in horizontal, vertical and diagonal directions. And right figure shows Lena which is a well-known test image containing various edges in various directions. This slide explains the measurement conditions. To investigate the increase in the range of accommodation responses, we changed the interval viewpoints among 2.6, 5.3 and 7.9 millimeters by displaying identical products images at 2 or 3 adjacent viewpoints. The viewing angle of test images was 2.8 degrees by 2.8 degrees. Observation distance was 350 millimeters. The distance to test image from the display screen was from 105 millimeters behind the screen to 75 millimeters in front of the screen. The number of trial was 3. And in each trial, the responses were measured in 2 seconds. And the responses within 2 seconds without blinking were averaged. And the number of subjects was 5. We used order estimator grand cycle FR5500S. And for comparison, we measured the accommodation responses to real target. So this slide shows the typical results obtained for multi-cloth of subject HN. This figure shows the accommodation responses to real object. And this figure shows the accommodation responses to 3D images for viewing interval of 2.6, 5.3 and 7.9 millimeters. In each figure, horizontal axis shows the distance to test target. And vertical axis shows the measured accommodation responses. Most values are represented in the after unit, which is reciprocal of length in meters. And these diodes show the average pupil diameter in the trials. And in this study, in this study, the range of accommodation responses obtained for 3D images to be obtained for all distances is defined as DOF. Usually, the depth of field DOF is depth range in which an object can be imaged without blur. And from these results, the DOF obtained for viewing interval of 2.6 millimeters was greater than the DOF obtained for other view interval. The DOF might increase because the extent of rates at the pupil was smaller than the pupil diameter when view interval was 2.6 millimeters. And because accommodation responses are different between subjects, so we compare the responses to real object to responses to 3D images. Horizontal axis shows the accommodation responses to real object. And the vertical axis shows the responses to 3D images. When 3D image was displayed in DOF range, the accommodation responses to 3D image was approximately equal to the responses to real object. On the other hand, the 3D image was displayed outside the DOF, the accommodation responses became saturated. And these figures show the accommodation responses to Lena obtained for same subject, HN. The results were very similar to those for multiple scrolls. When the view interval was 2.6 millimeters, the DOF was greater than the DOF obtained for other view intervals. In measurement results, we found that there are two tendencies of accommodation responses to Lena when view interval was 2.6 millimeters. In this slide, we show the results for the first group. For three subjects, the ranges of accommodation responses for Lena were similar to those for the multiple scrolls. And these figures show the results for the other group. For these two subjects, the range of accommodation responses for Lena were smaller than those for the multiple scrolls. These subjects might pay attention to the types of edges other than the particular one contained in Lena. So from the results, the HP or assembly display still evoked the accommodation responses even when Lena, that contains various types of edges, was displayed. So to investigate the blur in the retinal images according to the accommodation responses, we captured retinal images using a camera. This slide shows the evaluation method. The camera focus was changed to three different positions such as display screen, 3D image, and eye accommodation positions. This figure shows the typical accommodation responses to real images. This range is the DOF to obtain the four 3D images. From the accommodation responses to real target, we can estimate focus positions of subjects eyes. And we use these estimated focus positions as eye accommodation positions. The other conditions are shown in this table. The interval view point was 2.6, 5.3, and 7.9 millimeters. The distance between the camera and the screen was 350 millimeters. And the distance to test images from the screen was plus and minus 45 millimeters. We used a cool CCD camera to capture the images. These photographs are the retinal images of multi-scrub, displayed at 45 millimeters in front of the screen. These figures show these photographs are the images when the view interval was 2.6 millimeters. These photographs are retinal images when the view interval was 5.3 millimeters. And these figures were captured when the view interval was 7.9 millimeters. And these figures are retinal images captured by camera focusing on 3D image. These images are retinal images captured by camera focusing on eye accommodation positions. And these figures are the retinal images captured by camera focusing on the display screen. So we first consider the case where the view interval was 2.6 millimeters. When the camera focused on the display screen, twin images was obtained. On the other hand, when the camera was focused on eye accommodation positions, single image was obtained. Therefore, the subject's eyes might focus on eye accommodation positions. And next, we consider the case where the view intervals was 7.9 millimeters. When the camera focused on the display screen, single image was obtained. And when the camera was focused on eye accommodation distance, there apparently blur was observed. So the viewers might have paid attention. The viewers might focus on the display screen. And these photographs are the retinal images. So, the camera is close, displayed at 45 millimeters behind the screen. The same results, we obtained the same results. When the camera focused on the screen, twin image, and the camera focused on the eye accommodation position, single image. And also, we obtained similar results for Lena. When the camera focused on the screen, the twin image was obtained. On the other hand, camera focused on eye accommodation position, single image. So, viewers eye might focus on the eye accommodation positions. And this is the result for Lena when the 3D image was displayed behind the screen. And we also obtained similar results. So I conclude my talk. The accommodation responses to the HP or SMV display measured. And we found that the HP or SMV display still evoked the accommodation responses, even when the standard test image, Lena, that contains various types of edge was displayed. And the amount of evoked accommodation for Lena were smaller than or similar to those for the test image containing obvious vertical edge, depending on where the subject gets. The blur in retinal image was investigated by capturing retinal image using a camera. Thank you for your attention. Okay. Just to clarify, when you said that you're capturing retinal images using a camera, you're simulating the eye using a camera. So your camera has the same focal distance as your eye would have? Yes, I use a camera. And the aperture diameter of the camera was same to the aperture diameter of subjects. The pupil of the subject's eyes, same pupil in the camera, same focus distance. Same diameter. I guess follow up the previous question. And I think I just want to make sure that you confirm that the focal length of the camera is the same as the human vision system, because even though the pupil diameter is the same, but the depth of field of your camera is not necessary the same as the human eye. You mean the DOF? Yes, the focal length is very critical in this case, not just the pupil diameter. I guess I just want to make sure we understand the focal length is also matched. What is the focal length of the camera? The focal length of the camera I use was 60 millimeters. I think that's a really important result. That's really encouraging for volumetric displays, multifocal displays, that so few viewpoints seem to stimulate accommodations. That's a really important result. And it's great. But I have one kind of technical question about the way you measure accommodation. Accommodation can be voluntary or involuntary in humans. And the way we often tell whether it's voluntary or involuntary is by the dynamics, how fast it occurs, and whether it occurs in the right direction. So my question is, what do you know about the time variation of the accommodation response that you observed? Was it fast? Was it slow? Did it sometimes go the wrong direction and come back? That would give us some way to assess the degree to which it was voluntary versus involuntary. I'm sorry, I don't understand your question. Let's talk about it later. But it's a really nice result. Thank you. So you mean time axis. So you mean we should evaluate the accommodation in time axis. You mean so? Yeah. When you're trying to, so you can, through voluntary effort, through your will, you can make an accommodation that's not natural. You can say, oh, that looks blurry. I'm going to try something and then sharpen it. But when you do that, it's slow and it often goes the wrong direction first. And so you can use the time course of your accommodation responses to help us decide whether this is a natural involuntary response that you measured or whether it's an unnatural voluntary response. I'll talk to you about it during coffee. I can sort of draw it out for you. Okay. Thank you. But nice paper. Okay. We are running out of time. So thank you, speaker. Thank you very much. Thank you.
accommodation causes visual fatigue while viewing conventional 3D displays. Supermultiview display accommodation conflict. An ideal SMV display should generate dense viewpoints in both horizontal and vertical directions. However the SMV displays developed so far are the horizontal parts only type because of system complexities. Therefore the accommodation measurements were distinctive vertical edge. So in this study we contained in 3D images upon the accommodation responses evoked by HP or SMV display. In the we used two types of test images to investigate the influence of the edge properties contained in which contains sharp edges in horizontal, responses to Lena when view interval was 2.6 ranges of accommodation responses for Lena were display still evoked the accommodation responses even when Lena, that contains various types of edges, was displayed. So to investigate the blur SMV display measured. And we found that the HP or responses, even when the standard test image, for Lena were smaller than or similar to those edge, depending on where the subject gets. The