Abstract:
In one embodiment, a system generates a succession of selected visual perception task images for presentation to a person, and receives respective inputs from the person based on the person&#39;s perception of each image, wherein subsequently generated images are based at least in part on the person&#39;s perception of one or more previously presented images. The generation and modification of images based on the person&#39;s input is repeated until at least one characteristic of the person&#39;s visual perception capabilities is adequately evaluated, improved to a desired level, or both.

Description:
FIELD OF THE INVENTION 
   The invention relates generally to the field of vision improvement and, more specifically, to identifying and improving visual perception and acuity abilities, and improving the visual perception process and neural performance of a person over a communication network. 
   BACKGROUND INFORMATION 
   Human eyesight is a product of two separate processes that work together to form images for a person to “see.” One of these processes, herein referred to as the physical component, concerns the physical structure of the various elements of the eye and how incoming light is manipulated and processed by the eye. Defects in the shape of the cornea, the retinal wall, or the optic nerve can impair or destroy the functionality of a person&#39;s eye and thus impair or eliminate the ability to perceive images. Fortunately, defects in the cornea of a person can be corrected through the use of glasses, contacts, or surgery such as laser keratotomy. Likewise, defects in the retina of a person are often repairable by surgery. 
   The second process involved in allowing humans to see images is herein referred to as the neurological component. This component concerns neural processing in the brain and how the brain analyzes information sent from the eyes to produce an image. A person can likewise have a number of defects in this component of the visual process, such as reduced visual acuity, reduced sensitivity for spatial contrast, reduced vernier acuity, spatial distortion, abnormal spatial interactions and impaired contour detection. 
   The physical component and the neurological component work together to form images that a person sees, or more precisely, that a person perceives. The term “perceives” is preferred because, although the physical component may capture certain details, defects in the neurological component may distort and destroy these details, therefore, the image that is “seen” by the person may not be exactly what is captured by the eyes. Consequently, the image that is perceived may differ in detail from the image that is seen by the eyes. Thus, the overall process of human eyesight is herein referred to as the visual perception process. 
   Defects in the neurological component of a person&#39;s visual perception process cannot be remedied through the use of corrective lenses or surgery. Therefore, alternate techniques must be employed to alleviate or correct visual defects in the neurological component of a person&#39;s visual perception process. 
   For example, a common defect in the neurological component of the visual perception process is a condition known as amblyopia. This is a perception defect where the brain incorrectly interprets and processes visual information it receives from the eyes, despite the fact that the physical structure of the eyes may be unimpaired. When addressing amblyopia in children, one approach to correcting defects in the neurological component is to occlude the non-amblyopic, dominant eye and “force” the brain to make greater use of the amblyopic eye. This approach generally strengthens the amblyopic eye and increases its visual acuity. But a significant shortcoming of this approach is that this method is typically only useful in children under the age of nine, and beyond that age the method generally provides insignificant results. Furthermore, occlusion of the non-amblyopic eye is accomplished through the use of an unsightly eye patch, and this often results in social and emotional problems for children. The eye patch may cause skin irritation, as well. 
   Amblyopic observers suffer from many or all of the neurological defects mentioned above, such as reduced visual acuity, reduced sensitivity for spatial contrast, reduced vernier acuity, spatial distortion, abnormal spatial interactions and impaired contour detection. Amblyopes may also have abnormally high degrees of intrinsic noise, which may form the basis of their abnormal contrast sensitivity function. 
   SUMMARY OF THE INVENTION 
   Systems and methods for evaluating, quantifying and improving a person&#39;s visual perception capabilities are provided. 
   In one embodiment, a system generates a succession of selected visual perception task images for presentation to a person, and receives respective inputs from the person based on the person&#39;s perception of each image, wherein subsequently generated images are based at least in part on the person&#39;s perception of one or more previously presented images. The generation and modification of images based on the person&#39;s input is repeated until at least one characteristic of the person&#39;s visual perception capabilities is adequately evaluated, improved to a desired level, or both. 
   Other and further aspects and advantages of the invention will become apparent from the following detailed description and accompanying drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the figures of the accompanying drawings, like reference numbers correspond to like elements, in which: 
       FIG. 1  illustrates one embodiment of a Visual Perception Task Image. 
       FIG. 2  illustrates a second embodiment of a Visual Perception Task Image. 
       FIG. 3  illustrates further embodiments of Visual Perception Task Images. 
       FIGS. 4A through 4D  illustrate two embodiments of Visual Perception Tasks. 
       FIGS. 4E and 4F  illustrate another embodiment of a Visual Perception Task. 
       FIGS. 5A through 5D  illustrate four more embodiments of Visual Perception Tasks. 
       FIGS. 6A through 6D  illustrate two more embodiments of Visual Perception Tasks. 
       FIGS. 7A through 7D  illustrate two more embodiments of Visual Perception Tasks. 
       FIG. 8  is a simplified diagram of an internet-based system for identifying, quantifying and improving visual perception abilities of a person, in accordance with the invention. 
       FIGS. 9 and 10  are flowcharts depicting methods for identifying, quantifying and improving visual perception abilities of a person from the perspective of a host server in the system of  FIG. 8 . 
       FIG. 11  is a flowchart depicting methods for identifying, quantifying and improving visual perception abilities of a person from the perspective of a client terminal in the system of  FIG. 8 . 
       FIG. 12  illustrates an embodiment of a system configured to carry out methods for identifying, quantifying and improving visual perception abilities of a person, in accordance with the invention. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Terminology 
   As used herein, the term “Visual Perception Task Image” or “VPT Image” refers to an image generated for use in testing, treating, or improving a person&#39;s visual perception process. 
   As used herein, the term “Visual Perception Task” or “VPT” refers to a visual perception test or task employing one or more VPT images in order to measure or improve a person&#39;s visual perception process. 
   As used herein, the term “Visual Perception Task Session” or “VPT Session” refers to a plurality of VPTs that are presented to a person to test or improve their visual perception process. Each VPT Session is generally designed to target a specific aspect of the visual perception process. 
   Visual Perception Task Images 
   Beginning with  FIG. 1 , an exemplary Visual Perception Task Image (VPT Image) is shown. The VPT Image  100  of  FIG. 1  comprises a single target Gabor patch  102  designed to activate neurons in the visual cortex. It should be noted that the VPT Image  100  can take the form of any visual stimulus, and is not limited to Gabor patches. 
   The Gabor patch  102  is a luminance pattern defined by a collection of odd (sine) and even (cosine) wave functions with limited spatial extent (and/or temporal extent). These functions are referred to as Gabor functions. The Gabor functions include variables that describe the pattern orientation, wavelength (width of a single black-white cycle) and spread of the Gaussian envelope. 
   Gabor functions are significant because they have been shown to efficiently describe the shape of receptive fields in the mammalian visual system. Neurons in the primary visual cortex receive retinal inputs with weights distributed over space in a shape that fits the Gabor function. In humans, it has been shown that visual pattern detection is performed by multiple localized filters, each covering a range of retinal space, orientations and wavelengths. The filters weigh visual input by a function that fits the Gabor function, each filter having its own parameter set (location, orientation, wavelength). These detectors underlie both pattern detection and segmentation. 
   Another VPT Image  100  is illustrated in  FIG. 2 , this time comprising a central target Gabor patch  102  flanked by two more Gabor patches  104  of similar orientation and spatial frequency placed laterally of the central Gabor patch. In this embodiment, the target Gabor patch  102  preferably coincides with a fixation point of an observer (the target patch  102  being fovean) sitting a distance of about 0.5–2.5 meters from a display screen presenting the VPT image. The Gaussian envelope size (σ=λ=0.15°) may be such that at least one cycle is within a range of ±σ from the Gaussian center. The carrier spatial frequency of the Gabor patches may be 6.6 cycles per degree (λ=0.15°) and mask contrast may be 40%. The distance d between the target Gabor patch  102  and the flanking patches  104  may be 1.5λ. The initial contrasts of the patches may be in the range of 8–50%, for example. In short, each visual image is characterized by a parameter comprising at least one of a contrast, a spatial frequency, a distance between the images, a local and global orientation, presentation time, and possibly other parameters as well. 
   It should be noted that the invention contemplates use of a number of alternative embodiments of the VPT Images  100 . This is because many visual perception deficiencies exist, and each deficiency generally requires a different set of VPT Images  100  to best identify the particular deficiency and work to improve it. Therefore, the invention contemplates using a large number of different VPT Images  100  to identify and improve many different types of visual perception deficiencies. These different VPT Images  100  use changes in parameters such as contrast, contours, spatial frequency, distance between the images, local and/or global orientations of the images, and other attributes to develop improved neurological function. Because the VPT Images  100  are typically computer-generated images, they may also be either static or dynamic. 
   Furthermore, the VPT Images  100  are not restricted to Gabor patches, but rather any kind of visual image, including straight lines, curved lines, or other shapes. The particular VPT Image  100  used is selected based upon which neurological functions require improvement. Accordingly, the embodiments shown in  FIGS. 1 and 2  are for purposes of illustration only, and are not meant as limitations on the invention. 
   Variations of the VPT Images of  FIGS. 1 and 2  may also be used. For example, another variation of the VPT Image  100  of  FIG. 1  may consist of sequentially adding one or more flanking Gabor patches  104  that are similar in appearance to the target Gabor patch  102 . And for the VPT Image  100  of  FIG. 2 , a variation may consist of rotating the local orientations of the Gabor patches  102  and  104 , as well as their global orientation. Examples of alternate variations of the VPT Images are shown in  FIG. 3 . 
   Visual Perception Tasks 
   A Visual Perception Task (VPT) comprises one or more VPT Images  100  that are presented to a person in sequence, wherein at least one of the VPT Images  100  generally includes a target. As used herein, the term “target” refers to a specific portion of the VPT Image that the person is expected to focus on or detect, such as a Gabor patch or some other visual stimulus. 
   When two or more VPT Images  100  are used in a VPT, generally less than all of the VPT Images  100  used will contain the target. For example, if two VPT Images  100  are used, one VPT Image  100  will have a target that the person is expected to detect while the other VPT Image  100  will not. And when a VPT comprises only one VPT Image  100 , the person is generally expected to detect some characteristic of the image, such as whether a target Gabor patch is offset from flanking Gabor patches, or whether a contour can be seen. 
   The one or more VPT Images  100  are shown to a person during the VPT, and the person is then asked to perform the VPT by identifying the target or the characteristic of the image. The VPTs vary, thus there may be a single static or dynamic VPT Image used in a VPT, or there may be two or more VPT Images displayed in sequence. 
   After the VPT is presented, the person is asked to provide a response (or “input”) based upon his or her perception of the VPT Images  100 . For example, the person can be asked to indicate whether he or she perceived the target, or whether the target has been offset from flankers. The person can provide this input through a variety of mechanisms, for instance by answering a yes/no question, a multiple choice question, a true/false question, a right/left question, or other similar questions. 
   The person provides the input using an input device such as a computer keyboard or mouse. Other input means, such as voice recognition, touch-screens, joysticks, trackballs, computer pens, or touch-pads can also be used. For some VPTs, such as those testing perception of contours, the input may not be a response to a question, but rather, the person may indicate a perceived contour formed by the images using a mouse to outline the contour. 
   One or more further VPTs are then generated and presented to the person based, at least in part, upon the person&#39;s response to the preceding VPT. Normally, if the person correctly performed the preceding VPT and detected what was expected, the further VPT can be configured to be more difficult. Or if the person was unable to perform the preceding VPT, the further VPT can be configured to be easier to perceive for the person. Alternately, and particularly when the level of difficulty is at or near the person&#39;s threshold, the further VPT can be designed to maintain the same level of difficulty. This taxes the person&#39;s visual perception process and further works the person at the thresholds of his or her visual perception abilities. These further VPTs are preferably generated until the person is no longer making progress in the particular treatment session. 
   More particularly, the further VPTs are generated by varying one or more parameters associated with the VPT Images  100 . These parameters may include, but are not limited to, contrast, spatial frequency, distance between images, local and global orientation, and the duration of time an image is displayed. Combinations of parameters may be manipulated as well, such as contrast and exposure duration of the VPT Image  100 . As explained in greater detail herein, these parameters are quantified and expressed in numerical terms to allow for analysis and manipulation using software containing functions and algorithms for this purpose. 
   The VPTs can be administered in different ways. Typically a person uses both eyes when performing the VPTs. However, the methods and systems of the invention can be used to build acuity in only one eye by blurring or covering the other eye. Then stereoscopic vision can be developed using both eyes. This technique is more adapted for use in adults. Further, especially in the case of children, entertaining content can be added to or built into the VPTs to keep their interest level high. 
   VPT Example 1 
   Turning now to  FIGS. 4A and 4B , an example of a VPT is shown where a person&#39;s contrast sensitivity is addressed. In this example, the VPT comprises two VPT Images  100 , one in  FIG. 4A  and the other in  FIG. 4B . The VPT begins with a person focusing on a target area, which is generally the center of the display screen. Some form of marker may be displayed prior to the VPT Images  100  being shown to aid the person in focusing on the target area. Next, the two VPT Images  100  are shown to a person in sequence. The VPT Image  100  of  FIG. 4A  appears on screen for a short duration of time, then no image is shown for a short duration of time, and finally the VPT Image of  FIG. 4B  is shown for a short duration of time. One of the two images contains the “target” that the person is expected to perceive. Here, the target appears in the second image, which is  FIG. 4B . 
   The person now provides an input to indicate which VPT Image  100  contained the target. Again, the appropriate user input in this example would be to acknowledge that the second image ( FIG. 4B ) contained the target. Once the person inputs a response, a further VPT is generated and presented to the person. 
   If the person has provided a correct response to the VPT of  FIGS. 4A and 4B , the next successive VPT will preferably be slightly more difficult. By way of example, this may be accomplished by decreasing the contrast of the VPT Images  100 . As shown in  FIGS. 4C and 4D , the new VPT Images  100  have a lower contrast, thereby making the target more difficult to perceive. The VPT Images  100  of  FIGS. 4C and 4D  can then be presented as a VPT for the person to perform. This decreasing of contrast level then continues as the person successfully performs the VPTs until the person is no longer able to perceive the target. 
   The order of the VPT Images  100  is random, which is why the order of the VPT Images in  FIGS. 4C and 4D  varies from that of  FIGS. 4A and 4B . And in the event the person provides an incorrect response, the contrast level can be increased to make the target easier to perceive. 
   Many variations of the VPTs of  FIGS. 4A through 4D  are possible. For instance, the number of Gabor patches used in each VPT Image  100  can vary. A VPT may comprise two VPT Images  100 , where one VPT Image  100  has a single Gabor patch and the other VPT Image  100  has no Gabor patches. Or, as shown in  FIGS. 4E and 4F , the VPT can comprise two VPT Images  100  where one VPT Image  100  has four Gabor patches and the other VPT Image  100  has five Gabor patches. Any other number of Gabor patches can be used for this type of VPT, as long as one VPT Image  100  of the VPT has “x” patches, and the other VPT Image has “x−1” patches. This ensures that the VPT can be used to determine whether a person can detect a target Gabor patch. It should be noted that if the VPT is using a plurality of Gabor patches, the target Gabor patch can be any of the patches and does not necessarily have to be the center patch of the image. 
   VPT Example 2 
   Turning to  FIGS. 5A through 5D , four more VPTs are shown that address vernier acuity. Here, each VPT comprises a single VPT Image  100  that contains three Gabor patches and is exposed to a person for a short duration of time. In each of these VPTs, the person is asked to indicate whether the central Gabor patch is offset to the left or right of the flanking Gabor patches. 
     FIGS. 5A through 5D  illustrate VPTs in descending order of difficulty, from greatest to least offset of the center Gabor patch. Therefore,  FIG. 5A  is the easiest VPT of the four, and  FIG. 5D  is the most difficult. As a person correctly performs the VPTs, the offset level will decrease towards what is shown in  FIG. 5D  and beyond until the person cannot detect an offset. And if the person incorrectly answers VPTs, the offset will head in the direction of  FIG. 5A  and beyond. 
   Variations of the VPTs of  FIGS. 5A through 5D  are also possible. For instance, the offset can occur in the top or bottom Gabor patch instead of the center Gabor patch. And in another variation, the three Gabor patches can be lined up diagonally or horizontally instead of vertically as is the case in  FIGS. 5A through 5D . 
   VPT Example 3 
   Turning now to  FIGS. 6A through 6D , two more VPTs are illustrated (FIGS.  6 A/ 6 B are the first VPT, and FIGS.  6 C/ 6 D are the second VPT). Here, each VPT comprises two VPT Images  100  where one VPT Image has three Gabor patches and the other has two, similar to  FIGS. 4A through 4D . The difference between these VPT Images and those of  FIGS. 4A through 4D  is that here, one of the Gabor patches is offset from the others. In  FIGS. 6A and 63 , the center Gabor patch is offset. And in  FIGS. 6C and 6D , the top Gabor patch is offset. 
   The offsetting of one of the Gabor patches tends to change how a person perceives the image. This is because the flanking Gabor patches tend to either facilitate or suppress detection of the target Gabor patch. Whether they facilitate or suppress depends on a number of factors, including contrast level of the flankers, distance of the flankers from the target, and the person&#39;s visual abilities. Thus, offsetting one of the Gabor patches, as done here, creates VPTs that differ than those of  FIGS. 4A through 4D . 
   In these VPTs, the person is again required to detect which VPT Image  100  has the target patch. In the VPT of  FIGS. 6A and 6B , the center Gabor patch is the target. In the VPT of  FIGS. 6C and 6D , the bottom Gabor patch is the target. 
   VPT Example 4 
   Turning now to  FIGS. 7A through 7D , two VPTs of another type are shown that address contrast sensitivity and lateral interactions. Here the Gabor patches are always aligned, but parameters such as distance between the patches and contrast can be varied. Each VPT comprises two VPT Images  100  where again one VPT Image  100  has a target patch. To make the VPTs more difficult, either the contrast level is lowered, or the distance between the Gabor patches increased, or both.  FIGS. 7C and 7D  illustrate how the VPT Images  100  of  FIGS. 7A and 7B  are configured when the distance between patches is increased. 
   As explained in greater detail herein, as a person progresses through the VPT Session, the parameter being manipulated, whether it is contrast level or another parameter such as offset, will reach a value that is close to the person&#39;s threshold or visual limitation and will tend to stabilize around an average value. This value, referred to herein as the “stabilized value”, can be used for many purposes, including to analyze the person&#39;s performance and to gauge whether the person is improving. This information is also used in configuring future VPTs for the person. Another useful value that is related to a VPT and used for analysis is a combination of the stabilized value and the VPT exposure duration. The VPT exposure duration refers to how long each VPT Image  100  was present on screen during the VPT. 
   For instance, in the VPT example of  FIGS. 4A through 4D , assuming the person successfully performs the VPTs, the contrast of the Gabor patches will decrease until a stabilized value is reached. This stabilized value, here relating to the threshold contrast value where the person can still perceive the target, is used when evaluating a person&#39;s performance. Another useful data item related to this type of VPT is a combination of the stabilized value and the frame exposure duration. 
   In the VPT example of  FIGS. 5A through 5D , if the person successfully performs the vernier acuity VPTs, the offset of the center Gabor patch will decrease until a stabilized value is reached, here relating to the threshold where the person can still detect an offset of one of the patches. Again, this stabilized value is used when evaluating a person&#39;s performance, and another useful data item here is a combination of the stabilized value and the frame exposure duration. 
   VPT Sessions 
   The administration of similar VPTs designed to target a specific aspect of the visual perception process is referred to as a VPT Session. For example, VPTs designed to improve a person&#39;s vernier acuity are referred to as a VPT Session for vernier acuity. Different VPT Sessions are designed to target all of the different aspects of the visual perception process, and preferred systems and methods utilize all of these different VPT Sessions. Generally, only one aspect of a person&#39;s visual perception process is targeted for improvement at a time, accordingly, one VPT Session is typically administered at each sitting. However, depending on time constraints, a single VPT Session can be administered over the course of two or more sittings. 
   Each VPT Session is made up of several series of VPTs. Although the VPTs contained in each series are very similar and address the same aspect of the person&#39;s visual perception process, each series has a slight variation from the others. For example, in the VPTs of  FIGS. 4A through 4D , the variation in each series can be the distance between the center Gabor patch and the flanking Gabor patches. As these series of VPTs are administered, each series will generate its own stabilized value, and the stabilized values from each series are then used to evaluate the person. 
   Communication Network Architecture 
   Turning to  FIG. 8 , preferred implementations of the invention may be performed using a host server  800  and a client terminal  820 . Host server  800  is a computer system  802  or device on a network with server software  801  configured to receive and answer requests for information. Typically, computer system  802  is also dedicated to storing data files and managing network resources, including network traffic. Computer system  802  or device generally includes a processor  804  and a data storage device  806 , and is typically connected to a global communication network, such as the Internet  840 . 
   Host server  800 , through processor  804 , has access to software  808  comprising sequences of instructions that cause processor  804  to perform a number of acts in accordance with the preferred methods described herein. In an alternative embodiment, host server  800  can also have access to a web page data storage device  810  that can store Hypertext MarkUp Language (HTML) documents defining web pages for communicating with persons, including HTML documents generated for the VPT Images  100 . Web page data storage device  810  can also store computer program scripts to generate web pages using an Active Server Pages (ASP) specification or Common Gateway Interface (CGI) specification. 
   Host server  800  also has access to a client database  812  that stores information concerning persons of the system. This information can include identification information and data relating to a person&#39;s performance during past VPT Sessions. In alternate embodiments, client database  812  may reside outside host server  800 , such as at client terminal  820 . 
   Client terminal  820  is a remote terminal that provides an interface for a person to access host server  800 . Client terminal  820  is typically a computer system  822  or device that is communicatively coupled to host server  800  by a communication network, such as the Internet  840 . Computer system  822  generally includes a processor  824 , a data storage device  826 , a display screen  828 , an input device  830 , and software  827  that comprises sequences of instructions that cause processor  824  to perform a number of acts in accordance with the methods described herein. An exemplary computer system for use in either the host server  800  or client terminal  820  is described below with reference to  FIG. 12 . 
   Administering Visual Perception Tasks Over a Communication Network 
   Host Server-Side 
   Turning to  FIG. 9 , a flowchart depicting a preferred implementation of a method of the invention is shown. The flowchart illustrates how the method is carried out at host server  800 . Starting with step  900 , host server  800  first receives a request from client terminal  820  for access to a VPT Session. This request is sent from client terminal  820  to host server  800  over a communication network, such as the Internet  840 . For ease of reference, the Internet will be the communication network referenced. It should be noted, however, that many other types of communication networks may be utilized by the invention. 
   Host server  800  can make itself accessible for such a request from client terminal  820  by providing an Internet website. Persons can visit the Internet website using a web browser such as Netscape Navigator (available at www.netscape.com) or Microsoft Internet Explorer (available at www.microsoft.com), or a specially developed web browser may be used to access the site. Persons can then directly request access to a VPT Session from host server  800 . 
   In step  902 , an authentication routine is performed to determine whether the request from client terminal  820  is valid. In other words, host server  800  determines whether the person that is trying to access a VPT Session is authorized to do so. Generally, host server  800  does this by sending a request over the Internet to client terminal  820  for a username and password. The data then received from client terminal  820  in response to the username and password request is typically transmitted to host server  800  over the Internet in an encrypted format, or using certificates, which prevents unauthorized persons from viewing the data. 
   Moving to step  904 , upon receiving the username and password data from client terminal  820 , host server  800  compares that data to username and password data stored in client database  812 . If host server  800  determines that the person is authentic, the process continues at step  906 . If the person is deemed to be non-authentic, a message is sent to client terminal  820  informing the person that access to the VPT Sessions is denied, as shown in step  918 . At that point, the person can be allowed to re-enter his or her username and password information a number of times. Generally, the number of times the person is permitted to re-enter the username/password information is limited to prevent persons from trying to gain unauthorized access. After a predetermined number of failed authentication attempts, host server  800  will typically ignore further requests from client terminal  820  for a predetermined length of time. 
   In step  906 , after host server  800  determines that the username and password supplied are genuine, a VPT Session is selected and an initial set of VPT Session parameters are generated. Typically, these parameters are defined in advance. The VPT Session is selected according to the methods described below with reference to  FIG. 10 , and the VPT Session parameters are generated as explained below with reference to step  916 . The VPT Session parameters define items such as contrast level, contours, spatial frequency, distance between objects, target placement, local and/or global orientations, and presentation time for each of the VPTs and VPT Images  100  being used to test or improve the visual perception process of a person. 
   Moving to step  908 , the initial VPT Session parameters are then delivered to client terminal  820  over the Internet  840 . Software resident on client terminal  820  is configured to receive the VPT Session parameters and use them to dynamically generate VPT Images  100  and VPTs. The VPT Session parameters transmitted can be encrypted, or can use certificates, for security purposes so no person can intercept the data. Once the parameters are delivered, the VPT Session can be carried out solely at client terminal  820  without the need for further interaction with host server  800 . This preferred configuration allows the VPT Session to be administered to the person without delay or interruption. 
   Alternatively, the VPT Session parameters can be sent as web pages in a format such as the Hyper-Text Markup Language (HTML) format. The web pages sent will generally be full screen pages, encompassing the entire viewable area of the display screen rather than appearing within a frame of a web browser. 
   In another alternative configuration, administration of the VPT Session can be carried out primarily by host server  800 , thus requiring data to be transferred back and forth between host server  800  and client terminal  820  during the session itself. 
   Moving to step  910 , after the VPT Session has been administered to the person, host server  800  receives a set of person performance data from client terminal  820 . The person performance data is data relating to the person&#39;s performance, which primarily comprises the stabilized values generated for each series of VPTs administered during a VPT Session, and can also include some or all of the user inputs received by client terminal  820 . The person performance data is generated by client terminal  820  and then sent back to host server  800  over the Internet  840 . This data can also be encrypted to prevent unauthorized persons from viewing the data. 
   In step  912 , host server  800  stores the person performance data it receives from client terminal  820 . The person performance data is generally stored on a data storage device, such as client database  812 . The data may alternatively be stored on data storage device  806 . This alternative may be preferred when, for instance, the personal information and medical records of clients are to be kept on a relatively secured storage device that is separate from the storage device that is storing the collection of user inputs. The data storage device  806  is further described below with reference to  FIG. 12 . 
   Moving to step  914 , the host server  800  next analyzes the person performance data to reveal any visual perception deficiencies, and to determine the level of performance of the person&#39;s visual perception process. Software  808  provides instructions and data for processor  804  to carry out this analysis. This is done by comparing the person performance data to data collected from persons with “normal vision,” i.e., based on generally acceptable levels of performance for each of the different aspects of the visual perception process, which helps gauge the person&#39;s level of performance. The processor  804  performs this comparison, using data related to that of a “normal observer,” which is stored in data storage device  806 . 
   When the VPTs contain flanking Gabor patches, it is also determined if the flankers tended to suppress or facilitate detection of the target Gabor patch. In addition, it is preferred data such as the person&#39;s personal medical data and history, results of past VPT Sessions, and statistical data for the general population be considered in the analysis. 
   Moving to step  916 , new VPT Session parameters are generated for use in the next VPT Session, based at least in part upon the person performance data that was received by host server  800 , and based at least in part upon the analysis conducted upon the person performance data by processor  804 . These new parameters again define specific VPT Images  100  and VPTs to further improve the person&#39;s visual perception ability based upon the person&#39;s level of performance. 
   Host server  800  uses software  808  to make these analyses and determinations. The software uses the person&#39;s performance data, and in particular the stabilized values generated for each series of VPTs in a given VPT Session. These stabilized values are then provided as input for one or more algorithms for generating new VPT Session parameters. 
   First, the algorithm(s) use the stabilized values to determine if the person&#39;s performance is better or worse than the most recent previous session. If the person&#39;s performance was better than the previous session, then the algorithm(s) determine if the person&#39;s performance has reached a “normal” level of performance. If it has, then the algorithm(s) trigger moving on to a different VPT Session. If the person&#39;s performance has not yet reached a “normal” level, the algorithm(s) increase the session difficulty. 
   If on the other hand the person&#39;s performance has worsened or is the same since the last session, the algorithm(s) ascertain whether the person&#39;s performance has not improved for a series of sessions, or if this may just be a temporary occurrence. If the person&#39;s performance has not improved over the course of several sessions, the algorithm(s) are configured to move on to the next VPT Session. This is because some persons will need other aspects of their visual perception process improved before they will show improvement on particular VPT Sessions. The person can then come back to this VPT Session at another time. Otherwise, the algorithm(s) will decrease the difficulty of the VPTs and administer the same VPT Session. 
   Once these algorithm(s) have been run and the next VPT Session parameters are set and stored until the person requests another VPT Session. It should be noted that the new VPT Session parameters are generally not at the person&#39;s thresholds. Instead, the difficulty level of the new VPT Session is lowered in order to allow the person to ease into the new VPTs that are at his or her thresholds. 
   In one embodiment, an “n over 1” staircase method is employed when making changes to a parameter, (e.g. contrast level), of the VPT Images  100 . What this means is that a person must correctly perform “n” VPTs before advancing to a more difficult VPT. The value of “n” preferably ranges from two to five. However, it only takes “m” incorrect responses to result in stepping back and decreasing the level of difficulty of the next VPT. Preferably, the value of “m” is one. This approach ensures that the person must truly make accurate perceptions in order to progress through the VPT Session. If the person is simply guessing and getting only 50% of the responses correct, statistically he or she will only step back and the VPTs will become easier because n&gt;m. Using the “n over 1” staircase, a person cannot move forward in the VPT Session by randomly guessing. 
   When the person provides “n” correct responses, a parameter of the VPT Images  100  is changed to make the next VPT more difficult. So for a parameter, such as contrast, a new contrast parameter is calculated using the formula:
 
Parameter NEW CONTRAST LEVEL =Parameter OLD CONTRAST LEVEL   /k  
 
where the parameter contrast levels are defined in numerical terms and “k” is a coefficient to compensate for certain effects on a person&#39;s performance which are unrelated to the person&#39;s visual perception or acuity abilities.
 
   Alternatively, when the person provides “m” incorrect responses, the next VPT is designed to be less difficult than the VPT that the person failed. Again using contrast level as the parameter to be changed, the new parameter for contrast level is calculated using the formula:
 
Parameter NEW CONTRAST LEVEL =Parameter OLD CONTRAST LEVEL   *k  
 
where, again, the parameter contrast levels are defined in numerical terms and “k” is a coefficient to compensate for certain effects on a person&#39;s performance which are unrelated to the person&#39;s visual perception or acuity abilities.
 
   Notably, the value of the “k” coefficient for a particular person may be derived empirically, e.g., based on general population studies, but is preferably individually determined and calibrated on an ongoing basis for every person. It&#39;s purpose is to compensate for certain effects on a person&#39;s performance that are unrelated to the person&#39;s visual perception or acuity abilities, such as
         1) Unusually high or low standard deviation. The gap between a person&#39;s best and worst performance may be quite large.   2) Weariness. A person&#39;s results are frequently much better at the beginning of a session then towards the end.   3) Suppression. Certain shapes on the screen may disturb a particular person&#39;s vision.   4) Facilitation. Providing a sound cue or some visual image on the screen may improve a person&#39;s performance.   5) Inconstancy. A person may make mistakes on very easy tasks that are unlikely for the particular person to fail, given his or her tested ability.       

   In some embodiments, a person may be assigned to a group of persons having similar performance characteristics and effects, and adopt a value for the “k” coefficient set for the entire group. 
   In another embodiment, when increasing or decreasing the difficulty of a VPT Session, the following weighted function is used to derive new parameters:
 
Parameter NEW VPT SESSION =(Parameter NORMAL −Parameter CURRENT )* k  
 
Notably, the parameter can be any of the ones mentioned herein, such as contrast level, or degree of offset.
 
   In embodiments of the invention where several persons will be accessing one client terminal  820 , such as at a clinic, client terminal  820  can download VPT Session parameters for a number of persons atone time. For instance, client terminal  820  may be in communication with host server  800  for a period of time, for example in the morning, to download VPT Session parameters for a number of persons. These persons can be persons who have scheduled appointments to access client terminal  820  during that day. This eliminates the need for constant or frequent on-line communications, and can also eliminate the need for individual usernames and passwords for persons as the entity running the client terminal can control who has access. 
   In this embodiment, the sets of person performance data generated during the numerous VPT Sessions administered to all of the persons can then be uploaded to host server  800  at one time. The data upload can take place anytime, for example during off peak hours, or even the next morning during the same period of time when new VPT Session parameters are being downloaded for that day&#39;s scheduled persons. It should be noted that the uploading and downloading of data may take place at any time of the day. 
   Notably, in various embodiments, the algorithm(s) may be different when working on different attributes abilities and even within a specific attribute, assuming a different state defined by the setup parameters—such as the combination of images size, display duration, orientation, gabor patch shape, etc. 
   In another embodiment, the VPT Images  100  are preformed and selected, rather than being generated dynamically. In such an embodiment, the VPT Session parameters comprise the specific VPT Images  100  themselves, rather than defining the images. 
   Selecting a VPT Session to Administer 
   Turning to  FIG. 10 , a flowchart is illustrated that demonstrates how a VPT Session is selected. There are two forms of VPT Sessions available, an evaluation phase to ascertain a person&#39;s visual perception ability, and a treatment phase to improve the person&#39;s visual perception. Accordingly, as shown in step  1000 , the first step in selecting a VPT Session is to determine whether the person has undergone the evaluation phase. If an evaluation has not been completed, the next step in the process is to move on to step  1002 . Otherwise, the flowchart will continue at step  1010 . 
   Starting with the evaluation phase and step  1002 , a person undergoes the evaluation to enable ascertaining the condition of the person&#39;s visual perception process. This data allows generation of effective VPTs that target the person&#39;s visual perception deficiencies. It also allows for a baseline set of data to gauge whether the person&#39;s visual perception is improving over the course of a particular VPT Session and over time. The evaluation process can be performed as often as necessary or desired. 
   Moving to step  1004 , user inputs and performance data from past VPT Sessions are analyzed. This data provides information that is useful for establishing parameters that select VPT Images  100  and VPT Sessions to use to evaluate the person&#39;s visual perception. For instance, if particular aspects of the person&#39;s visual perception have recently been evaluated, VPT Session is selected that evaluates a different aspect. Or if the user inputs from past VPT Sessions show that the person is deficient in a particular aspect of their visual perception, a VPT Session may be selected for further evaluating that particular aspect to determine whether there has been improvement or deterioration. 
   Moving to step  1006 , a VPT Session is selected from a first group of potential VPT Sessions. VPTs within each VPT Session are used to collect data from the person regarding different aspects of the person&#39;s visual perception process to detect the existence of any physical or neural defects. VPTs are used to test for any one or all of the following: 
   reduced visual acuity, 
   abnormal contrast sensitivity functions, 
   reduced vernier acuity, 
   spatial distortion, 
   abnormal spatial interactions, 
   impaired contour detection, 
   abnormally high degrees of intrinsic noise, 
   as well as other aspects of the person&#39;s visual perception. 
   Moving to step  1008 , once the VPT Session has been selected, parameters for the VPT Session are generated. These parameters define the VPT Images  100  and VPTs that are to be presented to the person, and in particular control the difficulty of the VPTs as well as other characteristics. Again, data from past VPT Sessions, including VPT Session parameters generated in accordance with step  916  of  FIG. 9  above, can be used in setting these parameters. 
   Moving to step  1010 , a treatment phase is initiated for improving various aspects of the visual perception process of a person and alleviate visual perception deficiencies. The flow of the treatment phase is almost identical to that of the evaluation phase. 
   Moving to step  1012 , user inputs from past VPT Sessions are analyzed. Next, as shown in step  1014 , a VPT Session is selected from a second group of VPT Sessions. This second group of VPT Sessions is different than the group described for the evaluation phase. Here, the second group of VPT Sessions comprises the following: 
   a lateral masking treatment VPT Session, 
   an acuity treatment VPT Session, 
   an elongated stimuli treatment VPT Session, 
   a stereoscopic treatment VPT Session, 
   and other treatment VPT Sessions. 
   Moving to step  1016 , as was the case for the evaluation phase, once a VPT Session has been selected, parameters are generated which, again, define the VPT Images  100  and VPTs that are to be presented to the person. Data from past VPT Sessions can be used in generating these parameters, including VPT Session parameters generated in accordance with step  916  of  FIG. 9  above. 
   Client Terminal-Side Methods 
     FIG. 11  is a flowchart illustrating how preferred methods are carried out at client terminal  820 . Starting with step  1100 , client terminal  820  receives a request for a VPT Session from a person. For example, a person can arrive at client terminal  820  and enter a request for a VPT Session using an input device, such as a keyboard, at client terminal  820 . The process of requesting a VPT Session generally comprises visiting a web site, such as a home page or authentication page provided by host server  800 , and entering a username and password. The software that requests the username and password may be located on either host server  800  or client terminal  820 . 
   Moving to step  1102 , the VPT Session request and username/password information is sent from client terminal  820  to host server  800  over a communication network, such as the Internet  840 . Again, the Internet will be used herein as the communication network. This transmission of data can be encrypted or use certificates to prevent others from accessing the username and password information. 
   In step  1104 , client terminal  820  receives a response from host server  800  that either allows or denies access to a VPT Session. The response is transmitted over the Internet  840  and is sent after host server  800  has determined if the username and password supplied are authentic. As shown in step  1106 , if the person is authentic and access is granted, the process continues at step  1108 . Alternately, if host server  800  determines that the person is not authentic, access to a VPT Session is denied and the process ends with a message to the person indicating the denial of access. 
   Moving now to step  1108 , VPT Session parameters for the current VPT Session are delivered to client terminal  820  from host server  800 . These VPT Session parameters are used to define the VPTs, and VPT Images  100 , that are presented to the person. The process of generating the VPT Session parameters was explained above with reference to steps  906  and  916  of  FIG. 9 , and steps  1008  and  1016  of  FIG. 10 . 
   Client terminal  820  has software residing on it configured to administer VPT Sessions to a person, and generally only requires VPT Session parameters from host server  800  to deliver the VPT Session. The software can be sent to client terminal  820  in any of a number of ways, including by Internet download, or via installation off of a magnetic or optical disk. 
   In step  1110 , the person&#39;s visual perception is calibrated. The visual perception ability of a person can vary from day to day based on a variety of factors such as stress, energy level, fatigue, previous meals, time spent in front of a computer screen or television, and many others. Therefore, one or more tests of the person&#39;s visual perception are preferably run to see if their visual perception ability is diminished due to these types of factors. 
   Moving to steps  1112  and  1114 , the collected calibration data is stored and the updated VPT Session parameters are downloaded during step  1108 . The parameters are updated to compensate for any diminished visual perception ability detected during the calibration step  1110 , thereby making the current VPT Session more effective and efficient. For instance, it the person&#39;s visual perception abilities have diminished by a certain amount, the VPT Session parameters can be lowered by that same amount to compensate for the diminished visual perception ability. 
   Moving to step  1116 , the VPT Session is started. The VPT Session selected during the selection phase described in  FIG. 10  is used. 
   In step  1118 , one or more VPT Images  100  using the VPT Session parameters are generated. Again, the parameters provided by host server  800  may be used to generate the VPT Images  100  on the fly. In another embodiment, preformed VPT Images  100  may be used. 
   Moving to step  1120 , after the one or more VPT Images  100  have been generated, they are used in a VPT which is presented to the person. The techniques used in VPTs were explained above. 
   After the VPT is presented, as shown in step  1122 , an input from the person is received, which indicates whether or not the person correctly performed the VPT. As explained above, these inputs are used to gauge the person&#39;s visual perception ability and to analyze the person&#39;s performance over one or more VPT Sessions. The user inputs are also used to adjust the VPT Session parameters used in subsequent VPT Images  100 . 
   Moving to step  1124 , it is then determined whether the input demonstrates that the person has reached a predefined goal. This goal is set based on a variety of factors, including how the person has performed in previous VPT Sessions and during evaluation phases. An example of a goal can be to administer VPTs to the person until a desired level of improvement has been achieved, or until a certain number of incorrect responses has been received. 
   Moving to step  1130 , if the goal has not been met, new VPT Images  100  are generated for use in a subsequent VPT, again based on the VPT Session parameters, which can be modified as the VPT Session is administered. The new VPT Images  100  are generally variations of the previous VPT Images  100 , wherein parameters such as contrast, distance between objects, color, shape, size, or other parameters are changed. The new parameters can vary the difficulty level of the VPT that is displayed, generally based at least in part upon the person&#39;s inputs and performance over the preceding one or more VPTs. Once the new parameters are chosen, returning to step  1118 , the next set of VPT Images  100  are displayed. 
   Moving to step  1126 , after the goal has been reached, the inputs are accumulated into VPT Session results, and person performance data is generated. These results can later be analyzed to ascertain the condition of the person&#39;s visual perception process, and determine whether it is improving or regressing. 
   Moving to step  1128 , it is then determined whether the entire VPT Session has been completed. If so, the person performance data, including the stabilized values and accumulated user inputs, are sent to host server  800  over the Internet  840  as shown in step  1132 , and this particular VPT Session is ended. The person performance data can be sent to host server  800  in an encrypted format, or using certificates, to prevent unauthorized persons from viewing that individual&#39;s input data. If the VPT Session has not been completed, returning back to step  1118 , new VPT Images  100  are generated to continue the current VPT Session. 
   Hardware Overview 
     FIG. 12  is a block diagram of an exemplary computer system  1200  upon which preferred methods of the invention are implemented. The computer system of  FIG. 12  can be used for host server  800 , and/or for client terminal  820 . 
   Computer system  1200  includes a bus  1202 , or other communication mechanism for communicating information, and a processor  1204  coupled with bus  1202  for processing information. Computer system  1200  also includes a main memory  1206 , such as a random access memory (“RAM”), or other dynamic (or “volatile”) storage device, coupled to bus  1202 . The main memory  1206  stores information and instructions executed by processor  1204  during execution. Main memory  1206  also stores temporary variables or other intermediate information during execution of instructions by processor  1206 . 
   Computer system  1200  further includes a read only memory (“ROM”)  1208  or other static (or “persistent”) storage device (e.g., FLASH, PROM, EEPROM, etc.) coupled to bus  1202 . The ROM  1208  stores static information and instructions for processor  1204 . It is worth noting that one or more banks of memory can comprise ROM  1208 . A storage device  1210 , such as a magnetic disk or optical disk (or “hard disk”, or “hard drive”), or another form of persistent storage device, is coupled to bus  1202 . The storage device  1210  uses a computer readable medium to store information such as data structures and instructions, for example, accumulated user input data from completed VPT Sessions, processor executable instructions (i.e. software) configured to carry out the methods described above with reference to host server  800  and client terminal  820 , and/or structures relating to the operating system or application programs that use the operating system. 
   Computer system  1200  is preferably coupled via bus  1202  to a display device  1212 , such as a cathode ray tube (“CRT”) or an active or passive-matrix display. The display  1212  presents images to an end-person, such as VPT Images  100 . An input device  1214 , including alphanumeric and other keys, is coupled to bus  1202 . The input device  1214  communicates information and command selections to processor  1204 . Another type of user input device is cursor control  1216 , such as a mouse, trackball, or cursor direction keys, for communicating direction information and command selections to processor  1204  and for controlling cursor movement on display  1212 . This input device  1214  typically has two degrees of freedom in two axes, a first axis (e.g., x) and a second axis (e.g., y), that allows the device to specify positions in a plane. 
   According to an aspect of the invention, the processor  1204  in the computer system  1200  executes one or more sequences of instructions (i.e. software  1205 ), contained in main memory  1206 . Such instructions are read into main memory  1206  from another computer-readable medium, such as storage device  1210  or ROM  1208 . The instructions can be executable object code or interpreted code that is processed by a run-time engine (e.g., Javascript). 
   Execution of the sequences of instructions contained in main memory  1206  causes processor  1204  to perform the methods of the invention as described herein, such as the methods described with reference to host server  800  and/or client terminal  820  above. In alternative embodiments, hard-wired circuitry can be used in place of or in combination with software instructions to implement the invention. Thus, embodiments of the invention are not limited to any specific combination of hardware circuitry and software. 
   The term “computer-readable medium” as used herein refers to any medium that participates in providing instructions to processor  1204  for execution. Such a medium can take many forms, including but not limited to, non-volatile media, volatile media, and transmission media. Non-volatile media includes, for example, optical or magnetic disks, such as storage device  1210 . Volatile media includes dynamic memory, such as main memory  1206 . 
   Transmission media includes coaxial cables, copper wire and fiber optics, including the wires that comprise bus  1202 . Transmission media can also take the form of acoustic or light waves, such as those generated during radio-wave and infrared data communications. 
   Common forms of computer-readable media include, a floppy disk, a flexible disk, a hard disk, a magnetic tape, or any other magnetic media, a CD-ROM, any other optical media, punchcards, a paper-tape, any other physical media with patterns of holes, a RAM, a ROM, a FLASH, or any other memory chip or cartridge, a carrier wave as described hereinafter, or any other media from which a computer can read. 
   Various forms of computer-readable media can be involved in carrying one or more sequences of one or more instructions to processor  1204  for execution. For example, the instructions can initially be carried on a magnetic disk of a remote computer. The remote computer can load the instructions into its dynamic memory and send the instructions over a telephone line using a modem. A modem local to computer system  1200  can receive the data on the telephone line and use an infrared transmitter to convert the data to an infrared signal. An infrared detector coupled to bus  1202  can receive the data carried in the infrared signal and place the data on bus  1202 . Bus  1202  carries the data to main memory  1206 , from which processor  1204  retrieves and executes the instructions. The instructions received by main memory  1206  can optionally be stored on storage device  1210  before or after execution by processor  1204 . 
   Computer system  1200  also includes a communication interface  1218  coupled to bus  1202 . Communication interface  1218  provides a two-way data communication coupling to a network link  1220  that is connected to a local network  1222 . For example, communication interface  1218  can be an integrated services digital network (“ISDN”) card or a modem to provide a data communication connection to a corresponding type of telephone line. As another example, communication interface  1218  can be a local area network (“LAN”) card to provide a data communication connection to a compatible LAN. Wireless links can also be implemented. In any such implementation, communication interface  1218  sends and receives electrical, electromagnetic or optical signals that carry digital data streams representing various types of information. 
   Network link  1220  preferable provides data communication through one or more networks to other data devices. For example, network link  1220  can provide a connection through local network  1222  to a host computer  1224  or to data equipment operated by an Internet Service Provider (“ISP”)  1226 . ISP  1226  in turn provides data communication services through the Internet  1228 . Local network  1222  and Internet  1228  both use electrical, electromagnetic or optical signals that carry digital data streams. The signals through the various networks and the signals on network link  1220  and through communication interface  1218 , which carry the digital data to and from computer system  1200 , are exemplary forms of carrier waves transporting the information. 
   Computer system  1200  can send messages and receive data, including program code, through the network(s), network link  1220  and communication interface  1218 . In the Internet example, a server  1230  might transmit requested code for an application program through Internet  1228 , ISP  1226 , local network  1222  and communication interface  1218 —for example using the FTP protocol. In accordance with the invention, one such downloaded application is executable software code or computer configuration parameters that perform the methods of the invention. 
   The received code can be executed by processor  1204  as it is received, and/or stored in main memory  1206 , storage device  1210 , or other non-volatile storage for later execution. In this manner, computer system  1200  can obtain application code in the form of a carrier wave. 
   Thus, methods and systems for analyzing and improving the visual perception process of a person have been disclosed. It should be noted that the disclosed methods and systems are useful for improving the visual perception of any person, no matter whether the person has normal or abnormal visual perception. The invention can also be used to diagnose and improve the vision of observers suffering from problems such as amblyopia, myopia, hyperopia, presbyopia, super-normal vision, or dyslexia. Even persons with anatomical or functional problems, such as macular degeneration, can improve what vision they have with the methods and apparatus of the invention. In addition to treating visual perception, the methods and systems of the invention can also be used in diagnosing major depression. 
   While various embodiments of the invention have been shown and described, it will be apparent to those skilled in the art that numerous alterations may be made without departing from the inventive concepts presented herein. Thus, the invention is not to be limited except in accordance with the following claims and their equivalents.