Abstract:
A visual recognition improvement system includes a visual noise generation device for generating and emitting noise ridden light at a predetermined intensity for an improvement of visual recognition; and a reflective device for reflectively redirecting the noise ridden light emitted from the visual noise generation device. The noise ridden light is projected toward an eye of an operator of a moving mechanism at work by using the reflective device from a plurality of directions in an eyesight of the operator.

Description:
CROSS REFERENCE TO RELATED APPLICATION  
       [0001]     This application is based on and claims the benefit of priority of Japanese Patent Application No. 2004-366689 filed on Dec. 17, 2004, the disclosure of which is incorporated herein by reference.  
       FIELD OF THE INVENTION  
       [0002]     The present invention generally relates to a visual recognition improvement system.  
       BACKGROUND OF THE INVENTION  
       [0003]     In recent years, a headlight control system for assisting a driver of a vehicle to recognize an object such as a pedestrian or the like without alerting the pedestrian has been proposed (refer to Japanese Patent Document JP-A-2000-203335, for example). In the disclosure of this Japanese Patent Document, the headlight control system includes a first headlight for projecting a visible light towards a front space of the vehicle and a second headlight for projecting an ultraviolet light toward a front space of the vehicle. The ultraviolet light projected from the second headlight shines on clothes worn by the pedestrian, and reflects back toward the driver of the vehicle. That is, the pedestrian is lit up by the ultraviolet light. Therefore, the driver of the vehicle can visually recognize the pedestrian ahead of the vehicle, and the pedestrian is not alerted by the ultraviolet light even when he/she sees the ultraviolet light from the second headlight.  
         [0004]     However, reflection intensity of the ultraviolet light used in the conventional headlight control system is affected by the color and material of the clothes of the pedestrian. That is, the intensity of the reflection of the ultraviolet light varies largely depending on the color of the clothes or the like. In addition, the driver can hardly recognize a small animal such as a dog, a cat or the like that may be lit up by the ultraviolet light because their coats are not very reflective. As a result, the headlight control system conventionally used for improvement of visual recognition of the object such as the pedestrian may not provide an intended improvement of the visual recognition when the ultraviolet light is not sufficiently reflected on the object.  
       SUMMARY OF THE INVENTION  
       [0005]     In view of the above-described and other problems, the present invention provides a system that is intended for an improved visual recognition to a viewer (i.e., a driver of a vehicle or the like).  
         [0006]     A visual recognition improvement system of the present invention uses a visual noise that has a suitable intensity for visual recognition of an object based on a threshold of visibility, and provides the visual noise for the driver while he/she is driving a vehicle from a plurality of directions towards the eyes of the driver.  
         [0007]     The present invention is based on a research result regarding “Stochastic Resonance (SR),” disclosed in a thesis entitled “Functional stochastic resonance in the human brain: Noise induced sensitization of baroreflex system” by Hidaka et al., and published in Transactions on Bionics and Physiology Symposium Vol. 15, pp 261-264.  
         [0008]     Stochastic resonance (SR) is an experimentally proven phenomenon that improves sensitivity of perception by statistically manipulating a small noise having an intensity below a threshold of perception for an organ of interest such as an eye, an ear or the like. Thus, SR is studied for improving human perception or a similar macro function. The area of improvement may include any macro facility such as perception, nerve control, behavioral operation or the like.  
         [0009]     SR is more practically explained with reference to the drawings.  FIG. 3A  shows an illustration of a human sensory system (e.g., a nerve cell) having a non-linear function. The human sensory system generally responds to an input having an intensity greater than a threshold by yielding an output, as shown in  FIG. 3B . That is, an input having an intensity below the threshold cannot be detected. Therefore, one aspect of the present invention implements SR to generate random noise having a broad frequency band for increasing the magnitude of the input and effectively improving the sensitivity of the human sensory system to detect an otherwise un-perceivable input. However, the random noise for improving the sensitivity should be carefully chosen in terms of its intensity.  FIG. 3C  shows a relationship between a signal noise ratio (SNR) and the random noise intensity. The relationship shown in the figure indicates that the random noise should neither be too strong nor too weak for the signal of interest to be perceived. That is, a certain intensity of the random noise, i.e., an optimum intensity, will maximize the SNR.  
         [0010]     The SR described above has an effect for improving perception such as a visual recognition of an object or the like. However, SR does not have a subliminal effect such as an enforcement of subconsciousness which is invoked by using repetitive provision of images, sounds or the like at an un-perceivable intensity.  
         [0011]     The visual noise generated in the above-described manner by using a light is projected toward the driver effectively improves the visual recognition of the driver of the vehicle. Further, movement of the eyes of the driver towards the upper/lower and/or right/left areas of his/her sight is covered by providing the visual noise from those directions. In this manner, the visual noise is effectively provided for the driver even when the driver&#39;s eyes are directed towards multiple directions.  
         [0012]     According to one aspect of the present invention, the visual recognition improvement system includes reflective devices as well as a noise generation device. That is, the visual noise generated by the noise generation device is projected towards the eyes of the driver and the reflective devices or other structures in the vehicle for being directly or reflectively injected into the eyes of the driver. In this manner, the movement of the driver&#39;s eyes to various directions such as, for example, a left direction for viewing a rear-view mirror, is always covered by the visual noise.  
         [0013]     Further, the visual noise reflectively redirected by a windshield of the vehicle is effectively injected into the driver&#39;s eyes, because the visual noise being reflectively redirected to the windshield by the reflective device does not include an unnecessary ghost image of a visual noise projecting portion of the visual recognition improvement system. In this manner, a single projection device can provide the visual noise from a plurality of directions by using a simple structure.  
         [0014]     According to yet another aspect of the present invention, the reflective devices may include mirrors disposed on an instrument panel of the vehicle. In this manner, the reflective devices effectively reflects the visual noise emitted from the noise projecting portion towards the driver without obstructing the sight of the driver.  
         [0015]     According to still yet another aspect of the present invention, the reflective devices may preferably be adjustable in terms of the direction of the reflection. In this manner, the drivers in, for example, various heights and positions can be covered.  
         [0016]     According to still yet another aspect of the present invention, the visual noise may be provided from a device disposed on an inner surface of the ceiling of the vehicle. In this manner, the visual noise is effectively provided for the driver of the vehicle. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0017]     Other objects, features and advantages of the present invention will become more apparent from the following detailed description made with reference to the accompanying drawings, in which:  
         [0018]      FIG. 1A  shows a block diagram of a visual recognition improvement system with a representation of visual noise provided for a driver in an embodiment of the present invention;  
         [0019]      FIG. 1B  shows a block diagram of a noise generation unit described with a user interface and a system structure;  
         [0020]      FIGS. 2A and 2B  show an illustration of devices of the visual recognition improvement system disposed in a vehicle with the visual noise emitted therefrom in the embodiment;  
         [0021]      FIG. 3A  is a block diagram of a human sensory system;  
         [0022]      FIG. 3B  a diagram showing a relationship of an input-output characteristic having a threshold; and  
         [0023]      FIG. 3C  is a diagram of the visual noise showing a relationship between a signal noise ratio and a noise intensity.  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0024]     An embodiment of the present invention is described with reference to the drawings.  
         [0025]      FIG. 1A  shows a block diagram of a visual recognition improvement system  1  and an illustration of provision of visual noise (noise ridden light) in an embodiment of the present invention, and  FIG. 1B  shows a block diagram of a visual noise generation device described with a user interface and an internal system structure.  
         [0026]     As shown in  FIG. 1A , the visual recognition improvement system  1  includes a visual noise generation device  10  and a reflective device  13 . The visual noise generation device  10  has a noise generation unit  11  for generating the visual noise and a noise output unit  12  for emitting the visual noise based on a signal from the noise generation unit  11 .  
         [0027]     The noise generation unit  11  includes a controller  11   a , a noise intensity memory unit  11   b , an optimum intensity setting unit  11   c , and a correspondence memory unit  11   d . That is, the noise intensity memory unit  1   b  memorizes a perceivable intensity of the noise as a threshold, the optimum intensity setting unit  11   c  sets an optimum intensity of the output noise based on the threshold memorized in the noise intensity memory unit  1   b , the correspondence memory unit  11   d  memorizes a combination of the optimum intensity of the noise with a driver&#39;s condition derived from a drivers condition recognition unit  31 , and a controller  11   a  for controlling the noise generation unit  11  by using the above described units  11   b ,  11   c ,  11   d.    
         [0028]     The controller  11   a  is coupled with operation switches  30  and the driver condition recognition unit  31 . The controller  11   a  defines the optimum intensity of the noise for a current condition of the driver based on the combination of the optimum intensity and the driver&#39;s condition memorized in the correspondence memory unit  11   d . The controller  11   a  also controls generation of the visual noise based on the optimum intensity determined in the above-described manner. The controller  11   a  sends a control signal to the noise output unit  12  for an output of the visual noise having the optimum intensity. The noise output unit  12  emits the visual noise from the noise generation unit  11  by controlling a light source based on the control signal. The light source used to emit the visual noise may be, for example, a light emitting diode (LED), a room lamp in a vehicle  2  or the like.  
         [0029]     The visual noise used for the improvement of visual recognition by inducing the stochastic resonance (SR) is preferably wideband noise having no intensity peak at any range of frequency. That is, the stochastic resonance in visual recognition is induced by using noises such as, for example, a random noise having constant intensity at the visible band and/or a 1/f noise having intensity inversely proportional to frequency.  
         [0030]     However, the visual noise having a wide range of frequency band may not be having a sufficient intensity nor an appropriate intensity relative for suitably enhancing the visual recognition by inducing the SR. In this case, the signal noise ratio (S/N ratio) in the output signal is decreased.  
         [0031]     Therefore, the intensity of the visual noise used for visual recognition improvement should carefully be chosen. That is, for example, the optimum intensity of the visual noise is determined by an experiment to be stored in the visual recognition improvement system  1  for use in the visual noise generation in the noise generation device  10 . The control signal for generating the visual noise is outputted based on the stored intensity.  
         [0032]     Difference of the optimum intensities among individual drivers are accommodated by receiving feedback from each driver through the operation switch  30  while the controller  11   a  gradually increases the intensity of the visual noise outputted from the noise output unit  12 . The optimum intensity of the visual noise suitable for each driver can be captured and stored in the noise intensity memory unit  11   b  by having a feedback as a threshold of the noise intensity from the driver at the moment of recognition of the visual noise through the operation switch  30 . The optimum intensity setting unit  11   c  sets the optimum intensity of the visual noise for outputting the control signal of visual noise generation at the intensity of, for example, approximately 100% of the threshold intensity for the random noise, and approximately 69% of the threshold intensity for the 1/f noise. The proportion of the noise intensity for a sufficient signal noise ratio may be, for example, derived from an experiment. The percentage of the intensity against the threshold intensity may be variably controlled according to the situation of use of the visual recognition improvement system  1 .  
         [0033]     The driver condition recognition unit  31  may be, for example, a heart rate sensor for detecting a heart beat rate of the driver at the wheel. The detected heart beat rate may be used as an index of arousal. The heart beat rate may be detected by using devices such as a detector in a shape of a wrist watch, a device in a steering wheel for detecting the heart beat rate through blood pressure, a detection device in a seat or the like.  
         [0034]     The controller  11   a  may preferably increase the intensity of the visual noise by controlling the noise output unit  11  when the arousal of the driver detected by the driver condition recognition unit  31  is decreasing.  
         [0035]     The reflective device  13  includes a mirror for reflecting the visual noise from the visual noise generation device  10 . The mirrors in the reflective device  13  may be manually adjusted to have a suitable angle for reflection.  
         [0036]      FIGS. 2A and 2B  show an illustration of the visual recognition improvement system  1  disposed in the vehicle  2  with the visual noise emitted from the visual noise generation device  10 .  FIG. 2A  shows visual noise emission in the vehicle  2  shown in a side view of the vehicle  2 , and  FIG. 2B  shows visual noise emission in a room of the vehicle  2  illustrated as a view from a rear to a front.  
         [0037]     The one visual noise generation device  10  is disposed on the ceiling of the vehicle  2  in a portion in front of a head of the driver as shown in  FIG. 2A . The four reflection devices  13  are disposed on an instrument panel  20  as shown in  FIG. 2B . In this manner, the visual noise generation device  10  at the described position can effectively provide the visual noise to the eyes of the driver and the reflective devices  13  even when the device  10  is disposed only at one place in the vehicle  2 . The visual noise directly provided to the eyes of the driver designed to enter into the eyes when the driver is looking right front of the vehicle  2 .  
         [0038]     The reflective devices  13  are disposed at various positions so that the reflection of the visual noise enters into the eyes of the driver when the driver moves his/her sight away from the right front for confirmation of the rear view mirrors or the like. That is, the reflective devices  13  at right-most and left-most ends of the instrument panel  20  may be used, for example, to reflect the visual noise when the driver is looking into the rear view mirrors by horizontally moving the sight in a relatively large amount, and the reflective devices at a center of the instrument panel  20  may be used, for example, to reflect the visual noise when the driver is looking for a traffic light, a road sign or the like by vertically moving the sight in a small amount.  
         [0039]     The visual noise redirected by a front windshield  21  may effectively enters into the eyes of the driver without having a ghost image of the visual noise generation device  10  because of a reflection by an intermediate reflective device  13  in a path of the visual noise prior to a reflection by the front windshield  21 .  
         [0040]     The mirrors in the reflective device  13  may be held by using ball joints or the like for variable adjustment of the reflection angle. In this manner, various shapes and positions of the drivers can suitably be covered by the visual noise reflected by the mirrors in the reflective device  13 .  
         [0041]     The visual recognition improvement system  1  of the present invention may effectively provide the following effects for the user of the system. That is, (a) the visual noise directly emitted towards the driver can improve the visual recognition when the driver is looking right in a front space of the vehicle  2 , and the visual noise redirected by the mirrors of the reflective device  13  can improve the visual recognition when the driver is looking sideways for checking side mirrors or the like. In addition, (b) the visual noise generation device disposed only at one position can provide the visual noise from various directions towards the driver by using a simple system structure. Further, (c) the visual noise can effectively provided for the driver when the reflective device  13  including mirrors is disposed on the instrument panel  20 . Furthermore, (d) the visual noise can appropriately be provided for the driver when the mirrors in the reflective device  13  are manually controlled according to the shape and/or positions of the driver. Furthermore, (e) the visual noise generation device  10  in a front portion of the ceiling of the vehicle  2  relative to the head of the driver can effectively provide the visual noise for the driver and/or the reflective device  13 .  
         [0042]     Although the present invention has been fully described in connection with the preferred embodiment thereof with reference to the accompanying drawings, it is to be noted that various changes and modifications will become apparent to those skilled in the art.  
         [0043]     For example, the reflective device  13  may be disposed on a steering post or on the ceiling so that the device  13  does not interfere with the sight of the driver.  
         [0044]     Further, the visual noise generation device  10  may be disposed at a plurality of positions instead of having the reflective devices  13  in plural numbers. Furthermore, plural reflection devices  13  may be used in combination with the plural noise generation devices  10 .  
         [0045]     Such changes and modifications are to be understood as being within the scope of the present invention as defined by the appended claims.