Atr Auditory and Visual Perception Research Laboratories

Mitsuho Yamada

Kenya Uomori

Hiroshi Yoshimatsu

Keiichi Ueno

Norihito Nakano

Hitoshi Hongo

Naohiko Takahata

Mitsuru Fujii

Ryo Fukatsu

Shinji Murakami

Jiro Miyazawa

In an apparatus for examining gaze shift in depth direction, light emitting diodes B and E, or D and C are lit at a plurality of positions with different distance in depth direction from the subject, and eye movement of the subject at that time is detected by an eye movement detecting portion. The signal of detection is processed in a signal processing circuit and is applied to a calculating portion. The calculating portion determines whether or not there is a disorder in gaze shift in depth direction of the subject by using any or all of latency in eye movement, time constant, amplitude, change in convergence angle, number of occurrence of saccade, and asymmetry of left and right eye movements, in response to the detected output of the eye movement.

Apparatus for examining gaze shift in depth direction

A target is presented on a board for calculation, eye movement of a subject while he is gazing at the target is detected by an eye movement detecting portion, the output of which is converted into a digital signal in a signal processing circuit and it is applied to a calculating portion. The calculating portion calculates small involuntary movement data in response to the input digital signal to find a value of a fractal dimension and time dependence of the fractal dimension to determine a disease related to brain function, and the output of determination is provided from an output portion such as a printer.

Apparatus for detecting small involuntary movement

An image at a distant point and an image at a close point for generating depth perception of a subject are displayed on an image display monitor, and eye movement of the subject at that time is detected by an eye movement detecting portion. A calculating portion removes saccade component by using velocity or acceleration of the detected eye movement and calculates amplitude of vergence eye movement, change in convergence angle and cross-correlation of velocity or acceleration of the left and right eye movement to determine depth perception of the subject.

Apparatus for analyzing depth perception

When eye movement of a subject is detected by an eye movement detecting portion and head movement of the subject is detected by a head movement detecting portion, a line-of-sight calculating portion calculates the line-of-sight according to the detected outputs therefrom. A portion for generating an image to be presented generates an image as a task and presents the image to a task presenting portion. When a fixation point of the line-of-sight of the subject is determined by a fixation point determining portion, a mask image generated by a masking image generating portion is inserted to the task image by an image synthesizing portion, and it is presented at the task presenting portion. A portion for determining degree of advance of dementia determines degree of advance and possibility of Alzheimer's disease based on the particular movement of the line-of-sight of the subject at that time and on the percentage of correct answer to a prescribed task.

Apparatus for medical diagnosis utilizing masking of fixation point

In a medical diagnostic apparatus utilizing line-of-sight detection, targets are successively presented from different angles to the subject by a target presenting apparatus, eye movement of the subject while the subject is gazing at the target is detected by an eye movement detecting portion, the head movement of the subject is detected by a head movement detecting portion, and in response to the detection outputs, the spatial movement of the line-of-sight, rotation velocity component and translational velocity component of the head movement as well as the velocity component of the eye movement are calculated by a calculating portion, and the results are output to an output portion.

Medical diagnostic apparatus utilizing line-of-sight detection

In the medical diagnostic apparatus employing line-of-sight detection, eye movement and head movement of a subject are detected by eye movement detecting portion and head movement detecting portion, respectively, and images of the field of view of the subject are picked up by a TV camera. A calculating portion calculates a locus of the line-of-sight, a locus of the eye movement, the locus of the head movement, and vectors of spatial movement of the line-of-sight in response to the detected eye movement and the head movement. An image processing portion reduces the picked up image, a superimposer superimposes the images of the loci, the vector images and the images of the reduced field of view on each other, and the resulting images are displayed on a CRT display.

Flicks in one or both of eyes are measured by a sensor (1) employing a limbus reflection method. An output of the sensor is applied to and digitized by an A/D converter (2). The digitized output is applied to a computer (3). The computer calculates flicks data of eyeballs, then calculates fractal dimension simultaneously or individually in a time-elapsed manner or for a definite time period, and quantifies characteristics of the eyeball control systems from the value of the fractal dimension or the time dependence of the fractal dimension.

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Kyoto, Japan

Mitsuho Yamada