JP2016057906A - Measurement method and system of viewpoint position - Google Patents

Measurement method and system of viewpoint position Download PDF

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JP2016057906A
JP2016057906A JP2014184347A JP2014184347A JP2016057906A JP 2016057906 A JP2016057906 A JP 2016057906A JP 2014184347 A JP2014184347 A JP 2014184347A JP 2014184347 A JP2014184347 A JP 2014184347A JP 2016057906 A JP2016057906 A JP 2016057906A
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viewpoint position
line
imaging
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eyes
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圭司 松田
Keiji Matsuda
圭司 松田
憲二 河野
Kenji Kono
憲二 河野
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National Institute of Advanced Industrial Science and Technology AIST
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PROBLEM TO BE SOLVED: To provide a method for measuring a viewpoint position in a three-dimensional space with a level capable of measuring eye movement, by imaging both eyes with one frame.SOLUTION: Provided is a method for measuring a viewpoint position by imaging eyes of a subject. The method comprises: an imaging step for imaging both eyes with one frame; a visual line analysis step for analyzing an image acquired in the imaging step, and determining respective visual line directions of eyes by a pupil position shape and reflectance position shape; and a viewpoint position specification step for determining an intersection of the visual line directions.SELECTED DRAWING: Figure 1

Description

本発明は、被験者の眼球を撮像して視点位置を計測する方法及びその計測システムに関し、特に、上下左右方向とともに奥行き方向の三次元空間内における視点位置を計測する方法及びその計測システムに関する。   The present invention relates to a method for measuring a viewpoint position by imaging a subject's eyeball, and more particularly to a method for measuring a viewpoint position in a three-dimensional space in the depth direction as well as a vertical direction and a measurement system thereof.

被験者の眼球を撮像してモニター画面上の視点位置を計測する方法や計測システムが数多く提案されている。かかる計測情報はモニター画面の制御や周辺環境の各種制御などに利用される。一方、上下左右方向とともに奥行き方向の三次元空間内における視点位置を計測する方法及びその計測システムも提案されている。   Many methods and measurement systems for imaging the eyeball of the subject and measuring the viewpoint position on the monitor screen have been proposed. Such measurement information is used for control of the monitor screen and various controls of the surrounding environment. On the other hand, a method and a measurement system for measuring a viewpoint position in a three-dimensional space in the depth direction as well as in the vertical and horizontal directions have been proposed.

例えば、特許文献1では、それぞれが光源を備える2台のカメラで両眼球の視線を同時に測定することで三次元空間内における視点位置を計測する方法を開示している。具体的には、一方の光源を点灯させ該光源とともにあるカメラで一方の眼球の瞳孔を明るくしつつ撮影し、同様に、他方の光源を点灯させ該光源とともにあるカメラで他方の眼球の瞳孔を明るくしつつ撮影する。このとき、角膜反射の像も得られる。瞳孔位置及び角膜反射像から両眼球の視線ベクトルを求め、更に、輻輳角(両目の視線のなす角度)を求め、奥行き方向の視点(両目の視線の交差点)を計測するのである。   For example, Patent Document 1 discloses a method of measuring a viewpoint position in a three-dimensional space by simultaneously measuring the line of sight of both eyes with two cameras each having a light source. Specifically, one of the light sources is turned on and a camera with the light source is used to make the pupil of one eyeball bright, and similarly, the other light source is turned on and the camera with the light source is used to make the other eyeball pupil. Shoot while brightening. At this time, an image of corneal reflection is also obtained. The line-of-sight vector of both eyes is obtained from the pupil position and the cornea reflection image, and further the convergence angle (angle formed by the eyes of both eyes) is obtained, and the viewpoint in the depth direction (the intersection of the eyes of both eyes) is measured.

上記したように、カメラに対する視線ベクトルを求めることで、三次元空間内における視点位置を計測できる。ここで、カメラによって複数の画像を取り込み、反射光形状、瞳孔形状を計測し、反射光重心位置、瞳孔の楕円形状近似による短軸の傾き、短軸長軸比、瞳孔中心を計算することで、より正確且つ簡便に視線位置を三次元的に計測する方法も提案されている。   As described above, the viewpoint position in the three-dimensional space can be measured by obtaining the line-of-sight vector for the camera. Here, by capturing multiple images with the camera, measuring the reflected light shape and pupil shape, calculating the reflected light barycentric position, the minor axis inclination by approximating the elliptical shape of the pupil, the minor axis major axis ratio, and the pupil center A method of measuring the line-of-sight position three-dimensionally more accurately and simply has also been proposed.

例えば、特許文献2では、反射位置を角膜上に位置させるように配置された光源で照明された瞳孔をカメラで撮影し複数の画像を取り込み、得られたそれぞれの画像について、反射光重心位置と角膜曲率中心のx方向の距離及びy方向の距離、角膜曲率中心と瞳孔中心の距離を求め、反射光重心位置と瞳孔中心位置からカメラに対する視線ベクトルを求めて視線位置を三次元的に計測する方法が開示されている。   For example, in Patent Document 2, a pupil illuminated by a light source arranged so that the reflection position is positioned on the cornea is captured by a camera, and a plurality of images are captured. The distance in the x direction and the distance in the y direction of the corneal curvature center, the distance between the corneal curvature center and the pupil center are obtained, and the gaze vector for the camera is obtained from the center of gravity position of the reflected light and the pupil center position, and the gaze position is measured three-dimensionally. A method is disclosed.

また、特許文献3では、カメラ座標系で求めた視線ベクトルを対象物座標系における視線ベクトルに変換して被験者の視線位置を算出できること述べた上で、静止している眼球位置の計測だけでなく、眼球運動の計測までをも与える方法を開示している。ここでは、高速撮影可能なデジタルカメラを用いて、プログレッシブ方式のデジタル画像信号を直接コンピュータに入力し、デジタル画像処理を行う。主に、眼球の画像から瞳孔部分を近似した楕円の検出方法について述べている。   In addition, Patent Document 3 describes that the gaze vector obtained in the camera coordinate system can be converted into the gaze vector in the object coordinate system and the gaze position of the subject can be calculated, and not only the measurement of the stationary eyeball position. The method of giving even the measurement of eye movement is disclosed. Here, a digital image signal of a progressive method is directly input to a computer using a digital camera capable of high-speed shooting, and digital image processing is performed. It mainly describes a method for detecting an ellipse that approximates a pupil part from an eyeball image.

一方、特許文献4では、単眼カメラによって所定面を基準とした人物の視点を計測する方法を開示している。単眼カメラによって得られた撮影画像上において両眼球の位置を検出し、瞳孔間距離を求める。一方、単眼カメラの内部パラメータ(焦点距離等)と実空間上における既知の瞳孔間距離とを用いて、撮影画像上における瞳孔間距離を実空間上における視点距離(所定面と視点との距離)に換算するとしている。   On the other hand, Patent Document 4 discloses a method of measuring a person's viewpoint based on a predetermined plane with a monocular camera. The position of both eyes is detected on the photographed image obtained by the monocular camera, and the interpupillary distance is obtained. On the other hand, using the internal parameters of the monocular camera (focal length, etc.) and the known interpupillary distance in the real space, the interpupillary distance on the captured image is the viewpoint distance in the real space (the distance between the predetermined plane and the viewpoint). It is supposed to convert to.

特開2005−198743号公報JP 2005-198743 A 特開2005−13752号公報Japanese Patent Laid-Open No. 2005-13752 特開2014−61085号公報JP 2014-61085 A 特開2014−089304号公報JP 2014-089304 A

特許文献3でも述べられているように、従来の視線位置検出システムでは、静止している眼球位置の計測はできても、眼球運動の計測までは困難であった。つまり、眼球位置の計測からカメラに対する両眼球の視線ベクトルを求めてその交点として視線位置を三次元的に計測できるのであるが、両眼球のそれぞれの視線ベクトルが時間差を持って得られるなら、視線位置の計測は不正確なものとなってしまう。特に、両眼球をそれぞれ対応するカメラで撮像した場合、眼球運動の計測を行い得るレベルまで同期させることは非常に困難である。そこで両眼球を単眼で同時にカメラ撮像することが考慮される。   As described in Patent Document 3, the conventional gaze position detection system can measure the position of the stationary eyeball, but it is difficult to measure the eye movement. In other words, the line-of-sight vector of the binocular to the camera can be obtained from the measurement of the eyeball position, and the line-of-sight position can be measured three-dimensionally as its intersection, but if the line-of-sight vector of both eyes is obtained with a time difference, Position measurement will be inaccurate. In particular, when both eyes are imaged by corresponding cameras, it is very difficult to synchronize to a level at which eye movements can be measured. Therefore, it is considered to simultaneously capture images of both eyes with a single eye.

本発明は、上記したような状況に鑑みてなされたものであって、その目的とするところは、両眼球を1フレームに撮像して、眼球運動の計測を行い得るレベルで三次元空間内における視点位置を計測する方法及びその計測システムを提供することにある。   The present invention has been made in view of the situation as described above, and the object of the present invention is to capture images of both eyes in one frame and measure eye movement in a three-dimensional space. An object of the present invention is to provide a method and a measurement system for measuring a viewpoint position.

本発明による方法は、被験者の眼球を撮像して視点位置を計測する方法であって、両眼球を1フレームに撮像する撮像ステップと、前記撮像ステップで得られた画像を画像解析し、瞳孔位置形状及び反射光位置形状により前記眼球のそれぞれの視線方向を求める視線解析ステップと、前記視線方向の交点を求める視点位置特定ステップと、を含むことを特徴とする。   The method according to the present invention is a method for imaging a subject's eyeball and measuring a viewpoint position, the imaging step of imaging both eyes in one frame, image analysis of the image obtained in the imaging step, and pupil position The method includes a line-of-sight analysis step for obtaining a line-of-sight direction of the eyeball based on a shape and a reflected light position shape, and a viewpoint position specifying step for obtaining an intersection of the line-of-sight directions.

かかる発明によれば、両眼球の視線方向を左右の時間差なしで得ることができ、眼球運動の計測を行い得るレベルで三次元空間内における視点位置を計測することができる。   According to this invention, the line-of-sight direction of both eyes can be obtained without a time difference between left and right, and the viewpoint position in the three-dimensional space can be measured at a level at which eye movement can be measured.

上記した発明において、前記撮像ステップは、前記両眼球を面対称とする対称面上の位置から撮像するステップであることを特徴としてもよい。かかる発明によれば、両眼球までの距離を等しくして撮像できて、より正確な画像解析に基づいて、視点位置を正確に計測し得る。   In the above-described invention, the imaging step may be a step of imaging from a position on a symmetry plane in which the both eyes are plane-symmetric. According to this invention, the distance to both eyes can be made equal, and the viewpoint position can be accurately measured based on more accurate image analysis.

上記した発明において、前記視点位置特定ステップは、前記視線方向の水平方向の成分について前記交点を求め、前記交点を含む鉛直線上に前記視点位置を確定させることを特徴としてもよい。かかる発明によれば、比較的簡単に視点位置を確定できるとともに、水平方向及び鉛直方向の各々の二次元空間内で観察しやすい結果として視点位置の移動の軌跡を表示できる。   In the above-described invention, the viewpoint position specifying step may be characterized in that the intersection point is obtained for a horizontal component of the line-of-sight direction, and the viewpoint position is determined on a vertical line including the intersection point. According to this invention, the viewpoint position can be determined relatively easily, and the locus of movement of the viewpoint position can be displayed as a result of being easily observed in the two-dimensional space in each of the horizontal direction and the vertical direction.

また、本発明によるシステムは、被験者の眼球を撮像して視点位置を計測するシステムであって、両眼球を1フレームで撮像する撮像装置と、前記撮像装置で得られた画像を画像解析し、瞳孔位置形状及び反射光位置形状により前記眼球のそれぞれの視線方向を求める視線解析手段と、前記視線方向の交点を求める視点位置特定手段と、を含むことを特徴とする。   Further, a system according to the present invention is a system that images a subject's eyeball and measures a viewpoint position, and an image pickup device that picks up both eyeballs in one frame, and an image analysis of the image obtained by the image pickup device, It is characterized by comprising gaze analysis means for obtaining the respective gaze directions of the eyeball based on the pupil position shape and the reflected light position shape, and viewpoint position specifying means for obtaining the intersection of the gaze directions.

かかる発明によれば、両眼球の視線方向を左右の時間差なしで得ることができ、眼球運動の計測を行い得るレベルで三次元空間内における視点位置を計測することができる。   According to this invention, the line-of-sight direction of both eyes can be obtained without a time difference between left and right, and the viewpoint position in the three-dimensional space can be measured at a level at which eye movement can be measured.

上記した発明において、前記撮像装置は、前記両眼球を面対称とする対称面上の位置から撮像することを特徴としてもよい。かかる発明によれば、両眼球までの距離を等しくして撮像できて、より正確な画像解析に基づいて、視点位置を正確に計測し得る。   In the above-described invention, the image pickup device may pick up an image from a position on a symmetry plane in which the both eyes are plane-symmetric. According to this invention, the distance to both eyes can be made equal, and the viewpoint position can be accurately measured based on more accurate image analysis.

上記した発明において、前記視点位置特定手段は、前記視線方向の水平方向の成分について前記交点を求め、前記交点を含む鉛直線上に前記視点位置を確定させる手段であることを特徴としてもよい。かかる発明によれば、比較的簡単に視点位置を確定できるとともに、水平方向及び鉛直方向の各二次元空間内で観察しやすい結果として視点位置の移動の軌跡を表示できる。   In the above-described invention, the viewpoint position specifying means may be a means for obtaining the intersection point with respect to a horizontal component of the line-of-sight direction and determining the viewpoint position on a vertical line including the intersection point. According to this invention, the viewpoint position can be determined relatively easily, and the locus of movement of the viewpoint position can be displayed as a result of being easily observed in each two-dimensional space in the horizontal direction and the vertical direction.

本発明による視点位置の計測システムの(a)ブロック図及び要部の上面図、及び(b)要部の側面図である。BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1A is a block diagram of a viewpoint position measurement system according to the present invention, a top view of a main part, and FIG. 本発明による視点位置の計測方法のフロー図である。It is a flowchart of the measuring method of the viewpoint position by this invention. 視点位置の算出方法を示す上面図である。It is a top view which shows the calculation method of a viewpoint position. 視点位置の算出方法を示す側面図である。It is a side view which shows the calculation method of a viewpoint position. 視点位置の計測システムを用いて得られた視点位置の移動のうち(a)X−Z平面上の軌跡、(b)Z−Y平面上の軌跡を示す図である。It is a figure which shows the locus | trajectory on the (A) XZ plane among the movements of the viewpoint position obtained using the measurement system of a viewpoint position, (b) The locus | trajectory on a ZY plane.

本発明による視点位置の計測システムについて、図1を用いて説明する。   A viewpoint position measurement system according to the present invention will be described with reference to FIG.

図1に示すように、視点位置の計測システム1は、被験者Pの左右の眼球L及びRを撮像できる位置に備えられるカメラ2と、カメラ2の側部から眼球L及びRに向けて赤外線を照射するLED3と、カメラ2に接続されるコンピュータ10とコンピュータ10に接続される外部装置5とを備える。外部装置5は、測定結果を記録する記憶装置であるが、必要に応じてその他の装置も適宜選択される。   As shown in FIG. 1, the viewpoint position measurement system 1 includes a camera 2 provided at a position where the left and right eyeballs L and R of the subject P can be imaged, and infrared rays toward the eyeballs L and R from the side of the camera 2. An LED 3 to be irradiated, a computer 10 connected to the camera 2, and an external device 5 connected to the computer 10 are provided. The external device 5 is a storage device that records measurement results, but other devices are also selected as appropriate.

カメラ2は、広視野を撮像可能な単眼のハイスピードカメラであり、上記したように左右の眼球L及びRを同時に撮像できる位置に配置される。つまり、1フレームで左右の眼球L及びRを同時に撮像できる。特に、内蔵するイメージセンサなどにグローバルシャッタ機能を有していると1枚の画像の中の時間差を排除できて好ましい。また、カメラ2及びLED3は、眼球L及びRを面対称とする対称面S上に配置されると、後述する画像処理において有利になる。すなわち、カメラ2及びLED3からそれぞれの眼球L及びRまでの距離がほぼ等しくなり、解析すべき眼球L及びRに対応する画像の明るさをほぼ等しくでき、画像解析上の処理を比較的単純にできる。この場合において、図1(b)に示すように、カメラ2及びLED3は、被験者Pの視界を遮らないよう上方又は下方にオフセットされた位置に配置されるとよい。さらに、LED3は、両眼球L及びRの角膜上に反射光を形成するような位置に配置されている。   The camera 2 is a monocular high-speed camera capable of imaging a wide field of view, and is arranged at a position where the left and right eyeballs L and R can be simultaneously imaged as described above. That is, the left and right eyeballs L and R can be simultaneously imaged in one frame. In particular, it is preferable that a built-in image sensor or the like has a global shutter function because a time difference in one image can be eliminated. Further, if the camera 2 and the LED 3 are arranged on a symmetry plane S in which the eyeballs L and R are plane-symmetric, it is advantageous in image processing to be described later. That is, the distances from the camera 2 and the LED 3 to the respective eyeballs L and R are substantially equal, the brightness of the images corresponding to the eyeballs L and R to be analyzed can be substantially equalized, and the processing in image analysis is relatively simple. it can. In this case, as shown in FIG. 1 (b), the camera 2 and the LED 3 are preferably arranged at positions offset upward or downward so as not to block the field of view of the subject P. Furthermore, LED3 is arrange | positioned in the position which forms reflected light on the cornea of both eyes L and R. FIG.

被験者Pの前方には、被験者Pの視覚を刺激するためのディスプレー4が備えられる。ディスプレー4は、平面の画像表示装置などでもよいが、視点とすべきターゲットT1及びT2のように、被験者Pにとって前後方向の奥行きを異ならせて設けた複数のターゲットを備える立体的なものであると好ましい。   In front of the subject P, a display 4 for stimulating the vision of the subject P is provided. The display 4 may be a flat image display device or the like, but is a three-dimensional display including a plurality of targets provided with different depths in the front-rear direction for the subject P, such as the targets T1 and T2 to be viewed. And preferred.

コンピュータ10は、いわゆるパーソナルコンピュータなどであり、キーボードやモニタなど図示しない入出力装置を備える。コンピュータ10は、視点位置を計測するためのプログラムを実行することで、視線解析手段11及び視点位置特定手段12として機能する。   The computer 10 is a so-called personal computer or the like, and includes an input / output device (not shown) such as a keyboard and a monitor. The computer 10 functions as a line-of-sight analysis unit 11 and a viewpoint position specifying unit 12 by executing a program for measuring the viewpoint position.

視線解析手段11は、撮像した画像について画像解析を行い、かかる画像解析に基づいて、少なくとも両眼球L及びRの視線方向を求めることができる。ここでは、少なくとも画像解析を行って瞳孔の位置及び形状(瞳孔位置形状)と角膜上の反射光の位置及び形状(反射光位置形状)とを得て、その結果に基づいて幾何学的条件に従った計算等により左右の眼球L及びRのそれぞれの視線方向を得るのである。また、左右の眼球L及びRの回転中心及び、両眼球L及びRの眼球間距離を算出することもできる。なお、各眼球の視線方向を求める方法については以下に示す公知のシステムによる方法と同様の方法を用い得る。   The line-of-sight analysis unit 11 can perform image analysis on the captured image and obtain at least the line-of-sight directions of both eyes L and R based on the image analysis. Here, at least image analysis is performed to obtain the position and shape of the pupil (pupil position shape) and the position and shape of the reflected light on the cornea (reflected light position shape). The line-of-sight directions of the left and right eyeballs L and R are obtained by the calculation according to the above. It is also possible to calculate the center of rotation of the left and right eyeballs L and R and the distance between the eyes of both eyes L and R. In addition, about the method of calculating | requiring the gaze direction of each eyeball, the method similar to the method by the well-known system shown below can be used.

かかるシステムの1つは、頭部が固定された被験者において、反射位置が角膜上に位置するように配置された光源により照明された瞳孔を撮影可能のカメラによって、複数の画像を取り込む手段と、取り込まれたそれぞれの画像について、反射光形状及び瞳孔形状を計測して、反射光重心位置、及び瞳孔を楕円近似することにより短軸の傾き、短軸長軸比、及び瞳孔中心を計算する手段とを備え、あらかじめ計測しておいた反射光重心位置と角膜曲率中心のX方向の距離及びY方向の距離、角膜曲率中心と眼球回転中心の距離、瞳孔中心と眼球回転中心との距離を利用して、反射光重心位置と瞳孔中心位置からカメラに対する視線ベクトルを求めることから成る視線検出システムである。すなわち、取り込んだ画像を画像解析し、瞳孔位置形状及び反射光位置形状により眼球の視線方向を求めている。なお、角膜曲率中心は角膜を球の一部としたときのかかる球の中心であり、眼球回転中心は眼球が回転する際の不動点である。   One of such systems includes means for capturing a plurality of images by a camera capable of photographing a pupil illuminated by a light source arranged so that a reflection position thereof is located on the cornea in a subject whose head is fixed; Means for measuring the reflected light shape and pupil shape of each captured image, and calculating the inclination of the minor axis, the minor axis major axis ratio, and the pupil center by approximating the reflected light center of gravity and the pupil to an ellipse The distance between the center of gravity of the reflected light and the center of corneal curvature measured in the X direction and the distance in the Y direction, the distance between the corneal curvature center and the eyeball rotation center, and the distance between the pupil center and the eyeball rotation center are used. Thus, the line-of-sight detection system includes obtaining a line-of-sight vector for the camera from the position of the center of gravity of the reflected light and the center of the pupil. That is, the captured image is subjected to image analysis, and the line-of-sight direction of the eyeball is obtained from the pupil position shape and the reflected light position shape. The corneal curvature center is the center of the sphere when the cornea is part of the sphere, and the eyeball rotation center is a fixed point when the eyeball rotates.

また、他のシステムの1つは、頭部が固定されていない被験者において、反射位置が角膜上に位置するように配置された光源により照明された瞳孔を撮影可能のカメラによって、複数の画像を取り込む手段と、取り込まれたそれぞれの画像について、反射光形状及び瞳孔形状を計測して、反射光重心位置、及び瞳孔を楕円近似することにより短軸の傾き、短軸長軸比、及び瞳孔中心を計算する手段とを備え、あらかじめ計測しておいた反射光重心位置と角膜曲率中心のX方向の距離及びY方向の距離、角膜曲率中心と瞳孔中心の距離を利用して、反射光重心位置と瞳孔中心位置からカメラに対する視線ベクトルを求めることから成る視線検出システムである。すなわち、同様に、取り込んだ画像を画像解析し、瞳孔位置形状及び反射光位置形状により眼球の視線方向を求めている。   In another system, in a subject whose head is not fixed, a plurality of images can be captured by a camera capable of photographing a pupil illuminated by a light source arranged so that a reflection position is located on the cornea. Measure the reflected light shape and pupil shape for each captured image and the captured image, and reflect the center of gravity of the reflected light and elliptical approximation of the pupil, the minor axis inclination, the minor axis major axis ratio, and the pupil center The center position of the reflected light is calculated using the X-direction distance and the Y-direction distance of the reflected light centroid position and the corneal curvature center measured in advance, and the distance between the corneal curvature center and the pupil center. And a gaze detection system that obtains a gaze vector for the camera from the center position of the pupil. That is, similarly, the captured image is image-analyzed, and the eye gaze direction is obtained from the pupil position shape and the reflected light position shape.

視点位置特定手段12は、視線解析手段11によって得られた左右の眼球L及びRの視線方向の交点を求め、三次元空間内の視点位置を計測することができる。かかる計測方法の詳細については後述する。   The viewpoint position specifying unit 12 can obtain the intersection of the left and right eyeballs L and R obtained by the line-of-sight analyzing unit 11 in the line-of-sight direction, and can measure the viewpoint position in the three-dimensional space. Details of this measurement method will be described later.

次に、計測システム1による視点位置の計測方法について、図2乃至図4を参照しつつ、詳細に説明する。   Next, a method for measuring the viewpoint position by the measurement system 1 will be described in detail with reference to FIGS.

図2を参照すると、まず、被験者Pの左右の眼球L及びRをカメラ2により撮影しその画像を得る。すなわち撮像する(撮像ステップS1)。次いで、得られた画像について画像解析や幾何学的条件に基づく計算などを含んだ視線解析を行い、少なくとも左右の眼球L及びRの視線方向を求める(視線解析ステップS2)。ここで、両眼球L及びRの眼球回転中心及び眼球間距離(回転中心同士の距離)を併せて求めておくことが好ましい。視線方向等は、上記したような公知の方法によって求めることができる。さらに、得られた視線方向の交点を求めて三次元空間内の視点位置を特定する(視点位置特定ステップS3)。   Referring to FIG. 2, first, the left and right eyeballs L and R of the subject P are photographed by the camera 2 to obtain an image thereof. That is, imaging is performed (imaging step S1). Next, the line of sight analysis including image analysis and calculation based on geometric conditions is performed on the obtained image, and the line of sight directions of at least the left and right eyeballs L and R are obtained (line of sight analysis step S2). Here, it is preferable to obtain the eyeball rotation center and the interocular distance (distance between the rotation centers) of both eyes L and R together. The line-of-sight direction and the like can be obtained by a known method as described above. Further, the viewpoint position in the three-dimensional space is specified by obtaining the obtained intersection in the line-of-sight direction (viewpoint position specifying step S3).

詳細には、図3に示すように、左の眼球Lの眼球回転中心を原点とし、右の眼球Rの眼球回転中心をX軸上に配置し、被験者Pの正面に向かう水平方向をZ軸とし、鉛直上方をY軸方向とする(図4参照)よう座標を定める。ここで、眼球Lと眼球Rとの眼球回転中心距離はCであり、上記したように画像解析に基づく視線解析によって得られた眼球L及びRの眼球回転中心から求め得る。なお、眼球Lと眼球Rの眼球間距離は、例えば、個人差もあるが予め60mmとして定めておいて、簡易に視点位置を計測することもできる。被験者Pの頭の位置を固定することで、眼球位置を定めてもよい。   Specifically, as shown in FIG. 3, the center of eyeball rotation of the left eyeball L is the origin, the eyeball rotation center of the right eyeball R is placed on the X axis, and the horizontal direction toward the front of the subject P is the Z axis. And the coordinates are determined so that the upper vertical direction is the Y-axis direction (see FIG. 4). Here, the eyeball rotation center distance between the eyeball L and the eyeball R is C, and can be obtained from the eyeball rotation centers of the eyeballs L and R obtained by the line-of-sight analysis based on the image analysis as described above. Note that the interocular distance between the eyeball L and the eyeball R may be determined, for example, as 60 mm in advance, although there are individual differences, and the viewpoint position can be easily measured. The eyeball position may be determined by fixing the position of the head of the subject P.

まず、眼球Lの視線方向から左目水平角roax(単位:度)を得て、眼球Rの視線方向から右目水平角roaxR(単位:度)を得る。ここで、左目水平角roaxは正の値、右目水平角roaxRは負の値となる。さらに、求める視点位置Tを頂点の1つとして左右の眼球L及びRを結ぶ三角形において、視点位置Tと眼球Rとの間の辺の長さをA、視点位置Tと眼球Lとの間の辺の長さをB、眼球Lと眼球Rとの間の辺の長さを上記したようにCとする。つまり眼球間距離は回転中心同士の距離である。また、かかる三角形の角辺の対角はそれぞれa、b、cとする。すると、a=90−roax、b=90+roaxRである。つまり、角度a及びbは視線解析によって得られる左目水平角roax及び右目水平角roaxRによって記述でき、角度cも同様である。   First, the left eye horizontal angle roax (unit: degree) is obtained from the line-of-sight direction of the eyeball L, and the right eye horizontal angle roaxR (unit: degree) is obtained from the line-of-sight direction of the eyeball R. Here, the left eye horizontal angle roax has a positive value, and the right eye horizontal angle roaxR has a negative value. Further, in a triangle connecting the left and right eyeballs L and R with the desired viewpoint position T as one vertex, the length of the side between the viewpoint position T and the eyeball R is A, and the distance between the viewpoint position T and the eyeball L is The length of the side is B, and the length of the side between the eyeball L and the eyeball R is C as described above. That is, the interocular distance is the distance between the rotation centers. The diagonals of the corners of the triangle are a, b, and c, respectively. Then, a = 90−roax and b = 90 + roaxR. That is, the angles a and b can be described by the left-eye horizontal angle roax and the right-eye horizontal angle roaxR obtained by line-of-sight analysis, and the angle c is the same.

このとき、正弦定理により

Figure 2016057906
であるから、視点位置の座標(x,z)は以下のように記述できる。
Figure 2016057906
つまり、視点位置の水平方向成分(X−Z平面上の位置)は、左目水平角roax及び右目水平角roaxRから求められる角度a、b、cと、左右の眼球L及びRの間の距離Cとによって記述できる。 At this time, the sine theorem
Figure 2016057906
Therefore, the coordinates (x, z) of the viewpoint position can be described as follows.
Figure 2016057906
That is, the horizontal direction component (position on the XZ plane) of the viewpoint position is the distance C between the angles a, b, c obtained from the left eye horizontal angle roax and the right eye horizontal angle roaxR and the left and right eyeballs L, R. And can be described by

図4に示すように、鉛直方向成分(y)は、上記で求めたzと左の眼球Lによる視線方向から求めた左目鉛直角roayとを用いて以下のように記述できる。

Figure 2016057906
視点位置の座標のうちzは以下のように確定したから、
Figure 2016057906
これを、上記した式に代入してyを求めることができる。なお、右の眼球Rによる視線方向から求めた右目鉛直角roayRを用いても同様に、以下の式からyを求めることができる。
Figure 2016057906
As shown in FIG. 4, the vertical direction component (y) can be described as follows using z obtained above and the left eye vertical angle roay obtained from the line-of-sight direction of the left eyeball L.
Figure 2016057906
Since z of the coordinates of the viewpoint position is fixed as follows,
Figure 2016057906
This can be substituted into the above equation to obtain y. Similarly, y can be obtained from the following equation using the right eye vertical angle roayR obtained from the line-of-sight direction of the right eyeball R.
Figure 2016057906

上記したように、左目鉛直角roay又は右目鉛直角roayRの一方のみからyを求めてもよいが、両者からそれぞれyを求めて一致するかを確認したり、ずれの生じる場合にそれぞれ求めた2つのyを平均したりできる。また、左目鉛直角roay及び右目鉛直角roayRの平均値から、

Figure 2016057906
のようにyを算出するなど、適宜両者を使用してもよい。 As described above, y may be obtained from only one of the left eye vertical angle roay or the right eye vertical angle roayR. However, y is obtained from both of them to check whether they match each other, or 2 obtained when a deviation occurs. You can average two y's. Further, from the average value of the left eye vertical angle roay and the right eye vertical angle roayR,
Figure 2016057906
Both may be used as appropriate, such as calculating y as follows.

以上のようにして1フレームの画像から視点位置を計測できる。また、上記した撮像ステップS1、視線解析ステップS2、視点位置特定ステップS3を繰り返すことで、被験者Pの視線の移動による視点位置の移動を追従するように順次、視点位置を計測して、視点位置の移動の軌跡を得ることができる。   As described above, the viewpoint position can be measured from one frame image. In addition, by repeating the imaging step S1, the line-of-sight analysis step S2, and the viewpoint position specifying step S3, the viewpoint position is sequentially measured so as to follow the movement of the viewpoint position due to the movement of the line of sight of the subject P. The movement trajectory can be obtained.

図5に図1を併せて参照すると、被験者Pにディスプレイ4のターゲットT1及びT2を所定の規則で視認させ、被験者Pの視点位置を連続して計測した。かかる所定の規則は、中央手前のターゲットT1を基準位置として、これを視認した後、左上奥のターゲットT2を視認し基準位置を視認、右上奥のターゲットT2を視認し基準位置を視認、という視認の順番である。図5(a)は、水平方向の、すなわちX−Z平面上の視点位置の移動を示し、図5(b)は、鉛直方向の、すなわちZ−Y平面上の視点位置の移動を示している。以上のように、計測システム1を用いて被験者Pの視点位置の計測を行えば、両眼球L及びRの視線方向を時間差なしで得ることができ、眼球運動の計測を行い得るレベルで三次元空間内における視点位置を計測することができる。   Referring to FIG. 5 together with FIG. 1, the subject P was allowed to visually recognize the targets T1 and T2 of the display 4 according to a predetermined rule, and the viewpoint position of the subject P was continuously measured. The predetermined rule is that the target T1 in front of the center is regarded as a reference position, and after visually recognizing the target T2, the reference position is visually recognized, the target position T2 in the upper right rear is visually recognized, and the reference position is visually recognized. Is the order. 5A shows the movement of the viewpoint position in the horizontal direction, that is, on the XZ plane, and FIG. 5B shows the movement of the viewpoint position in the vertical direction, that is, on the ZY plane. Yes. As described above, if the measurement system 1 is used to measure the viewpoint position of the subject P, the line-of-sight directions of both eyes L and R can be obtained without a time difference, and the eye movement can be measured at a three-dimensional level. The viewpoint position in the space can be measured.

ここまで本発明による代表的実施例について説明したが、本発明は必ずしもこれに限定されるものではない。当業者であれば、本発明の主旨又は添付した特許請求の範囲を逸脱することなく、種々の代替実施例及び改変例を見出すことができるだろう。   Although the exemplary embodiments according to the present invention have been described so far, the present invention is not necessarily limited thereto. Those skilled in the art will recognize a variety of alternative embodiments and modifications without departing from the spirit of the invention or the scope of the appended claims.

1 視点位置の計測システム
2 カメラ
3 LED
10 コンピュータ
11 視線解析手段
12 視点位置特定手段
1 Viewpoint measurement system 2 Camera 3 LED
10 Computer 11 Line of sight analysis means 12 Viewpoint position specifying means

Claims (6)

被験者の眼球を撮像して視点位置を計測する方法であって、
両眼球を1フレームで撮像する撮像ステップと、
前記撮像ステップで得られた画像を画像解析し、瞳孔位置形状及び反射光位置形状により前記眼球のそれぞれの視線方向を求める視線解析ステップと、
前記視線方向の交点を求める視点位置特定ステップと、を含むことを特徴とする視点位置の計測方法。
A method of measuring a viewpoint position by imaging a subject's eyeball,
An imaging step of imaging both eyes in one frame;
An image analysis of the image obtained in the imaging step, and a line-of-sight analysis step for obtaining a respective line-of-sight direction of the eyeball from a pupil position shape and a reflected light position shape;
And a viewpoint position specifying step for obtaining an intersection in the line-of-sight direction.
前記撮像ステップは、前記両眼球を面対称とする対称面上の位置から撮像するステップであることを特徴とする請求項1記載の視点位置の計測方法。   2. The viewpoint position measuring method according to claim 1, wherein the imaging step is a step of imaging from a position on a symmetry plane in which the binocular balls are plane-symmetric. 前記視点位置特定ステップは、前記視線方向の水平方向の成分について前記交点を求め、前記交点を含む鉛直線上に前記視点位置を確定させることを特徴とする請求項1又は2に記載の視点位置の計測方法。   3. The viewpoint position determination method according to claim 1, wherein the viewpoint position specifying step determines the intersection point with respect to a horizontal component of the line-of-sight direction, and determines the viewpoint position on a vertical line including the intersection point. Measurement method. 被験者の眼球を撮像して視点位置を計測するシステムであって、
両眼球を1フレームで撮像する撮像装置と、
前記撮像装置で得られた画像を画像解析し、瞳孔位置形状及び反射光位置形状により前記眼球のそれぞれの視線方向を求める視線解析手段と、
前記視線方向の交点を求める視点位置特定手段と、を含むことを特徴とする視点位置の計測システム。
A system for measuring a viewpoint position by imaging a subject's eyeball,
An imaging device that images both eyes in one frame;
Line-of-sight analysis means for performing image analysis on the image obtained by the imaging device and obtaining the line-of-sight direction of the eyeball based on a pupil position shape and a reflected light position shape;
And a viewpoint position specifying means for obtaining an intersection in the line-of-sight direction.
前記撮像装置は、前記両眼球を面対称とする対称面上の位置から撮像することを特徴とする請求項4記載の視点位置の計測システム。   The viewpoint position measurement system according to claim 4, wherein the imaging device captures an image from a position on a symmetry plane in which the both eyes are plane-symmetric. 前記視点位置特定手段は、前記視線方向の水平方向の成分について前記交点を求め、前記交点を含む鉛直線上に前記視点位置を確定させる手段であることを特徴とする請求項4又は5に記載の視点位置の計測システム。   The said viewpoint position specific | specification means is a means to obtain | require the said intersection about the horizontal component of the said gaze direction, and to determine the said viewpoint position on the vertical line containing the said intersection. Viewpoint measurement system.
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JP2019028566A (en) * 2017-07-26 2019-02-21 楽天株式会社 Information processing apparatus, information processing system, information processing method and information processing program
CN111854658A (en) * 2020-07-22 2020-10-30 四川大学 R-test precision ball head detection device and calibration method thereof
CN111854658B (en) * 2020-07-22 2021-04-20 四川大学 R-test precision ball head detection device and calibration method thereof

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