Patent Publication Number: US-2015062372-A1

Title: Vision enhancing device

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a vision enhancing device for recording an object whereon text and/or at least one picture are visible, and for displaying the recorded object on a screen, said vision enhancing device being provided with:
         an object presenting unit comprising a bottom plate carrying a table for supporting an object to be displayed on a screen, said table being mounted to the bottom plate so as to be displaceable in at least two opposite directions in a horizontal plane;   an upstanding stand attached to the bottom plate;   a light sensitive sensor mounted to the upstanding stand for obtaining recording signals of the object, which signals represent an image of text and/or at least one picture on the object;   processing means for processing the recording signals into video signals; and   a screen, which, in use, is provided with the video signals for displaying an image of the recorded object on the screen.       

     Such a vision enhancing device is known in practice and is for example sold under the name “Optelec Clearview 2004-2012 generation” and is used by visually impaired persons. The object may for example be a newspaper or a magazine, comprising text and/or at least one picture. In use, the object is usually positioned on a flat table surface of the object presenting unit below the light sensitive sensor. By means of the light sensitive sensor the object is recorded and an image of the recorded object is projected on the screen. Also the sensor may comprise a zoom lens to enlarge the image for better viewing of certain parts of the text and/or at least one picture on the screen. By means of the processing means it is furthermore possible to enlarge or otherwise modify the image for better viewing of certain parts of the text and/or at least one picture. To position the object optimally with respect to the light sensitive sensor the object can be moved relative to the image field of the light sensitive sensor by displacing the table surface relative to the bottom plate in two opposite directions in a horizontal plane. Although the known vision enhancing enhancing device works more than satisfactory with objects having an A4 or letter size, using the vision enhancing enhancing device also for larger objects, such as e.g. having an A3 size or objects having, larger length dimensions, requires a relative bulky vision enhancing enhancing device having a large passive, i.e. stow away footprint. Furthermore, when handling objects having a larger size, there exists a risk that the position of the object is changed involuntarily e.g. by unintentionally touching the object. 
     Also there is a large (perceived) footprint, especially with regards to the area behind the monitor. Furthermore the position of stand at the back together with the position of the light sensitive sensor often causes the light sensitive sensor to look at the bottom part of the object in the starting position of the table, this has the following implications: 1. The table has to move towards the user if the user wants to read the top of the object, in this case the table movement can be limited if a user is closely positioned to the table  2 . a document that has a larger length dimension than A4 or letter, for instance some newspapers, have to be folded over a horizontal axis in order to read the whole document 3. For a user who reads from top to bottom, it is illogical to start at the bottom of the page. Moreover, when using the light sensitive sensor for providing an overview image on the of objects having a larger size, such as for example A3, the light sensitive sensor needs zoom factors in a relatively large range. For example a zoom factor 1 is required for providing the overview and zoom factors 3:54 or 1.5:28 for providing an enlarged image of a selected portion of the object on the screen. Thus a relatively large and thereby costly zoom range is required such as a zoom range from 1-52 or 1-28. Furthermore getting a full overview also requires either positioning the light sensitive sensor further away from the original object, which can have negative consequences on the design of the system, or a special lens is required, which can add additional costs and can have a negative impact on the image quality. 
     OBJECTS OF THE INVENTION 
     It is therefore an object of the invention to provide an improved vision enhancing enhancing device which meets at least some and possibly each of the above indicated problems. 
     SUMMARY OF THE INVENTION 
     In accordance with an aspect of the invention the vision enhancing device is characterized in that the upstanding stand is arranged to be positioned at a left or right side of the sensor and/or (a middle of) the screen (when viewed from a user position in front of the screen). Thus the upstanding stand is arranged to be positioned at a left or right side of (a middle of) the screen or sensor if the device is viewed from a user position in front of the screen and/or if the screen is mounted to the stand and viewed from a user position in front of the screen. This aspect of the invention is based on the insight that the problems related to the known vision enhancing device are at least partly the result of the fact that the stand is positioned behind the screen when viewed from the user. This positioning behind the screen requires a large depth of the vision enhancing device for displacing the table, especially when using large objects, having a length dimension larger than letter or a4 format, which makes the vision enhancing device bulky and requires a large desktop for supporting the vision enhancing device. By positioning the upstanding stand at a side, i.e. at a left or right side of the screen, the vision enhancing device can be arranged to have less depth, making it easier to move the table top forward and backward, i.e. away from or toward the user, respectively. In addition this arrangement provides a perception of free space and potentially a perceived smaller footprint as when using a monitor, for instance with a screen diagonal of 22 inch or 24 inch, the perceived width of the system is determined by the width of the monitor. Preferably at least an upstanding arm of the stand can be said to be complete on the left side (or the right side) of the sensor and/or the middle of the screen. 
     In a special embodiment the vision enhancing device comprises a stand which is displaceably mounted to the bottom plate in a direction from left to right or vice versa (when viewed from a position in front of the screen) in a horizontal direction parallel to the screen. In another embodiment the screen is displaceably mounted to the stand for displacing the screen relative to the stand in two opposite directions parallel to the screen. Such special embodiments enable reducing the footprint for stowaway or for use with relatively small objects such as A4 paper. In such embodiments preferably the vision enhancing device comprises first releasable tightening means arranged for, when tightened, fixing the position of the stand relative to the bottom plate and for, when released, allowing displacement of the stand relative to the bottom plate. More preferably the vision enhancing device comprises second releasable tightening means arranged for, when tightened, fixing the position of light sensitive sensor and/or the screen relative to the stand and for, when released, allowing displacement of the screen relative to the stand. In an advantageous embodiment the vision enhancing device can be realized in a compact manner when the upstanding stand is C-shaped and comprises a lower substantially horizontal arm, an upstanding arm and a substantially horizontal upper arm, wherein the bottom plate is provided with a connecting member for connecting the lower arm of the C-shaped upstanding stand to the bottom plate. 
     According to another aspect of the invention the vision enhancing device is characterized in that the device comprises at least one first table top which is removably mounted to the table, said first table top being arranged for supporting an object to be displayed on the screen. 
     This aspect of the invention is based on the insight that the problems related to the known vision enhancing device are at least partly the result of the fact that the supporting surface of the table for supporting an object to be displayed on a screen is fixedly attached to the object presenting table, thereby reducing the flexibility of the vision enhancing device. By removably mounting a first table top to the table, the flexibility of the vision enhancing device according to the invention can be improved, as a result of which it can be possible to use the vision enhancing device for objects of various sizes. 
     In an advantageous embodiment of a vision enhancing device according to the invention the device comprises interchangeable first and second table tops arranged for supporting an object to be displayed on the screen, said second table top being arranged for being removably mountable to the table. In this manner it is possible to change between table tops that are adapted to the size of the object, while the passive footprint of the vision enhancing device can remain relatively small, e.g. by removing a table top from the table. It is then particularly advantageous when the first table top has a first width dimension and a first length dimension, preferably being able to hold a A4 or Letter sized document and wherein the second table top has a second length dimension and a second width dimension, preferably being able to hold A3 sized documents. Preferably the vision enhancing device is arranged for allowing displacement of the table relative to the bottom plate and for allowing displacement of the stand relative to the bottom plate for obtaining a footprint which is formed by all possible positions of a respective table top relative to the bottom plate which is about twice the surface area of the respective table top. Thus the table can preferably at least be displaced relative to the bottom plate over its own full length and width. In particular when used with interchangeable table tops, such a displaceable mounting of the stand can readily convert the vision enhancing device from an operating position having a large footprint, e.g. when using objects having A3 size, to a stowaway position having a relatively small footprint, and vice versa. 
     In a user friendly embodiment the vision enhancing device according to the invention further comprises a user control input unit for controlling at least part of the operation of the vision enhancing device, said user control input unit being mounted to the table, which comprises a recess for docking the user control input unit. By providing the control unit on the table and e.g. not in the housing of the screen or located nearby the screen, a user of the vision enhancing device can place an object on the table top, position the object together with the table top in a desired position and control the operation of the vision enhancing device without lifting his or her hands from the table. In particular when the user control input unit is removably mounted to the table, said user control input unit preferably being a wireless user control input unit, the operation of the vision enhancing device can be very user friendly. Since the user control input unit is not hard-wired to the table but only has its cradle on the table, the user control input unit can also be used when not positioned in the table. In this manner it is possible in a preferred embodiment of the invention to provide e.g. control buttons on all sides of the user control input unit. Thus preferably the user control input unit is provided with two opposite sides wherein each side is provided with at least one control button and wherein the vision enhancing device is arranged such that the control input unit can be inserted in the recess such that upon selection either the first side is directed upwardly, permitting control of the at least one button provided on the first side; or the second side is directed upwardly permitting control of the at least one button provided on the second side, or such that upon selection either the first side is directed towards the user position for controlling the at least one button provided on the first side or the second side is directed toward the user position for controlling the at least one button provided on the second side. In particular the second side may comprise more control buttons than the first side. Thus, for example, the first side can be directed upwardly for providing basic control functions, and the second side can be directed upwardly for providing basic as well as more advanced control functions. 
     According to another aspect of the invention the vision enhancing device is arranged for positioning the light sensitive sensor above the bottom plate, and preferably for positioning the screen above the bottom plate. 
     A very user friendly vision enhancing device which is able to provide images of all the parts of an object placed on a table top is provided in an embodiment in which the vision enhancing device is arranged for allowing displacement of the table relative to the bottom plate and for allowing displacement of the stand relative to the bottom plate for obtaining a footprint for a respective table top which is about twice its surface area. 
     In a further embodiment of the invention the light sensitive sensor comprises an overview camera for providing overview recording signals of the object representing an image of the complete object; and a separate optical zoom camera, wherein the optical zoom camera is arranged for, in use, providing enlarged recording signals of the object representing an image of a part of the text and/or the at least one picture on the object, said processing means being arranged for optionally processing the overview recording signals such that the complete object is displayed on the screen, and for optionally processing the enlarged recording signals such that a part of the text and/or the at least one picture is displayed enlarged on the screen. By combining two separate cameras it is possible to extend the zoom range up to e.g. 54× or 27× by using standard available, inexpensive cameras. The overview camera provides a full overview of the object on the screen (for example by a fixed zoom factor 1)) while the optical zoom camera, preferably having a zoom range of 18, can provide a magnification from e.g. 1.5× to 27× or from 3× to 54×. Of course the overview camera may also provide smaller or larger magnifications than zoom factor lx, depending on the maximal size of the object to be overviewed. 
     In a further embodiment of a vision enhancing device according to the invention the processing means is arranged for, in use and upon user input, displaying the overview of the object and the enlarged part of the object alternately or simultaneously. In this manner the user can switch from one camera to the other, or simultaneously view the images to quickly find the magnified text on the object. 
     In a still further embodiment of a vision enhancing device according to the invention the light sensitive sensor further comprises a separate OCR-camera for obtaining OCR-recording signals, wherein the OCR-camera is arranged for, in use, providing the OCR-recording signals representing at least a part of the recorded object to the processing means for performing image analysis and/or image processing, and wherein the processing means are arranged for displaying the image analysis and/or processed images on the screen. In this manner image processing, such as image enhancement, contrast adjustment, or text recognition etc. can be performed by a specifically suited OCR-camera, thereby improving the visibility and the viewable size the images and/or textual information displayed on the screen. Preferably at least two, preferably all, cameras are mounted in a single housing for providing a compact vision enhancing device. 
     In a further embodiment of the invention a vision enhancing device is provided wherein the object presenting unit further comprises an intermediate mid-table, the table being mounted to the bottom plate via the intermediate mid-table, said intermediate mid-table being mounted on the bottom plate so as to be displaceable back and forth in a first direction of a horizontal plane, said first direction preferably being parallel to the screen, and wherein said table is mounted to the intermediate mid-table so as to be displaceable back and forth in a second direction of a horizontal plane, said second direction being perpendicular to the first direction, said object presenting unit further comprises a user operable first mechanical brake for, upon activation, preventing, or providing resistance to, displacement of the table in the first direction and a user operable second mechanical brake for, upon activation, preventing, or providing resistance to, displacement of the table in the second direction, wherein the mechanical brakes are operable independently from each other. In this manner a robust mechanical brake and friction function can be provided independently for both directions, which mechanical brake can be operated in an easy manner by a user of the vision enhancing device. 
     Preferably said first mechanical brake comprises a rigid longitudinal ridge fixed on the bottom table, said ridge extending in the first direction, at least a first rigid longitudinal ruler which is swivelably mounted on the intermediate mid-table around a swivel axis that extends in the first direction, and a plunger mounted on the intermediate mid-table, which plunger is—under user control—arranged for being positioned from an idle position to an active position, in which active position the plunger pushes the first ruler against the longitudinal ridge and in which idle position the ruler is free from the longitudinal ridge. Such a first mechanical brake can function effectively and reproducibly over an extended period of time. A particularly mechanical robust and compact vision enhancing device can be realized when the first mechanical brake comprises a wheel arranged for positioning said plunger in the idle position or the active position, said wheel being rotatable by a first worm wheel mounted on the intermediate mid-table, said first worm wheel being rotatable by means of a first control rod, wherein the first control rod is slidable along a longitudinal direction of the first control rod within the first worm wheel. Preferably a free end of the first rod is provided with a first gear wheel which is in engagement with a first rack that is slidably attached to the table in a direction parallel to the first direction. 
     Preferably said second mechanical brake comprises a rigid longitudinal brake rod attached to the table and extending in the second direction, and a brake shoe, which brake shoe is—under user control—arranged for being positioned from an idle position to an active position, in which active position the brake shoe engages the longitudinal brake rod and in which idle position the brake shoe is free from the longitudinal rod. Such a second mechanical brake can function effectively and reproducibly over an extended period of time. A particularly mechanical robust and compact vision enhancing device can be realized when the second mechanical brake comprises a brake shoe formed by two translatable rotatable brake shoe portions positioned at either side of the longitudinal brake rod, said rotatable brake shoe portions being translatable relative to each other by a second worm wheel mounted on the intermediate mid-table, said second worm wheel being rotatable by means of a second control rod, wherein the second control rod is slidable along a longitudinal direction of the second control rod within the second worm wheel. Preferably a free end of the second control rod is provided with a second gear wheel that is in engagement with a second rack that is slidably attached to the table in a direction parallel to the first direction. Preferably the vision enhancing device is provided with an eccentric that is engaged by the second worm wheel on the one hand for rotation of the eccentric upon rotation of the second worm wheel and which eccentric engages the brake shoe portions such that if the eccentric is rotated by the worm wheel in a first direction, a distance between the brake shoes is decreased for engaging or more engaging the brake rod and such that when the eccentric is rotated by the worm wheel in a second direction opposite to the first direction, the distance between the brake shoes is increased for disengaging or less engaging the brake rod. 
     In a still further embodiment of a vision enhancing device according to the invention the first rack is connected to a first handle, the second rack is connected to a second handle, said first and second handles being positioned below the recess. In this manner the handles can be positioned at one level, and next to each other, on the table for easy access and engagement by a user, which makes the vision enhancing device extremely user friendly in operation. It is noted that brakes may be arranged for fixing the movable table and/or for (steplessly) controlling the force required for moving the table relative to the bottom plate. 
     A particularly elegant and mechanical compact construction of the vision enhancing device can be realized when a wheel axle on which the wheel is rotatably mounted and the eccentric axle around which the rotatable eccentric is rotatably mounted coincide with each other. 
     In an embodiment of a vision enhancing device according to the invention in which the longitudinal brake rod is slidably received in a guiding channel, said guiding channel being mounted on the intermediate mid-table so that the backward and forward movements of the table top can be performed in a reproducible manner over an extended period of time. 
     To further clarify various aspects of embodiments of the present invention and additional features and advantages of the embodiments, a more particular description of various aspects and features will be rendered with reference to specific embodiments thereof, which are illustrated in the appended drawings. It will be appreciated that these drawings depict only exemplary embodiments of the disclosure and are therefore not to be considered limiting its scope, nor are the figures necessarily drawn to scale. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will now be further described with reference to the drawings, wherein: 
         FIG. 1A  shows an embodiment of an object presenting unit of a vision enhancing device according to the invention without a table top; 
         FIG. 1B  shows a first table top that can hold an object of A4 size for the object presenting unit of  FIG. 1A ; 
         FIG. 1C  shows a second table top that can hold an object of A3 size for the object presenting unit of  FIG. 1A ; 
         FIG. 1D  a portion of the device provided with a control input unit inserted in a first orientation; 
       FIG.  1 D′ a portion of the device provided with the control input unit of  FIG. 1D  inserted in second orientation 
       FIG.  1 D″ a portion of the device provided with the control input unit of  FIG. 1D  inserted in third orientation 
         FIG. 2A  shows an embodiment of a vision enhancing device according to the invention in a rear view in perspective, showing releasable tightening means for fixing the position of the stand relative to the bottom plate; 
       FIG.  2 A′ shows an alternative embodiment of a vision enhancing device according to the invention in a rear view in perspective, showing releasable tightening means for fixing the position of the stand relative to the bottom plate wherein the screen is attached to a separate stand as is schematically shown. 
         FIG. 2B  shows an embodiment of a vision enhancing device according to the invention in a rear view in perspective showing releasable tightening means for fixing the position of the screen and the light sensitive sensor relative to the stand; 
         FIG. 2C  shows an embodiment of a vision enhancing device according to the invention in a front view in perspective showing an object presenting unit with the first table top of  FIG. 1B ; 
         FIG. 2D  shows an embodiment of a vision enhancing device according to the invention in a front view in perspective showing an object presenting unit with the second table top of  FIG. 1C ; 
         FIG. 3A  schematically shows an embodiment of a light sensitive sensor of a vision enhancing device according to the invention comprising a zoom camera, a separate overview camera and a separate OCR camera; 
         FIG. 3B  schematically shows an example of an image of an object displayed on the screen recorded by the light sensitive sensor of  FIG. 3A ; 
         FIG. 4A  shows an embodiment of an object presenting unit of a vision enhancing device according to the invention without table top in which the mid-table and the table are displaced sideways relative to the bottom plate; 
         FIG. 4B  shows a part of  FIG. 4A  in an enlarged view; 
         FIG. 4C  shows a perspective view partly in cross-section of the object presenting unit of  FIG. 4A  along the line  4 C- 4 C; 
         FIG. 5A  shows an embodiment of a first and second mechanical brake for independently preventing or providing resistance to displacement of the table in the first and second direction, respectively, in a perspective view; 
         FIGS. 5B and 5C  show a top view of the second mechanical brake in an idle position and active position, respectively, for preventing or providing resistance to displacement of the table in the second direction, transverse to the screen; 
         FIG. 5D  shows a perspective view partly in cross-section of the first mechanical brake in an active position preventing or providing resistance to displacement of the table in the first direction, parallel to the screen; 
         FIG. 5E  details of the first and second mechanical brake; 
         FIG. 5F  an exploded view of a portion of details of the first and second mechanical brake; and 
         FIGS. 6A to 6D  schematically show the extreme positions of the table relative to the bottom plate in perspective. 
     
    
    
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     In  FIG. 1A  an embodiment of an object presenting unit  1  of a vision enhancing device according to the invention is shown without a table top. The object presenting unit  1  comprises a bottom plate  2  which can e.g. be placed on a desk top or other support surface (not-shown). An intermediate mid-table  3  is mounted on the bottom plate  2  so as to be displaceable back and forth in a first direction (indicated by the arrow FD in  FIG. 4C ) in a horizontal plane by means of for example a rail construction of which one rail part  4  is attached to the bottom plate  2  and the other rail part  5  is attached to the intermediate mid-table  3  (see  FIG. 4C ). As shown in e.g.  FIG. 1A  the object presenting unit  1  further comprises a table  6 , which is mounted to the intermediate mid-table  3  so as to be displaceable back and forth in a second direction SD in a horizontal plane, said second direction SD being perpendicular to the first direction FD. In this manner the table  6  is displaceable in two orthogonal directions in a horizontal plane with regard to the bottom plate  2 . 
     A first table top  7  ( FIG. 1B ) is removably mounted to the table  6  and is arranged for supporting an object, such as e.g. a newspaper, to be displayed on a screen of the vision enhancing device. For removably mounting the first table top  7  the table  6  can be provided with receiving holes  8  for receiving protrusions (not shown), which extend from the bottom surface of the first table  7 . In this manner table tops can be interchangeably mounted on the table  3 , so that e.g. the first table  7  can be interchanged with a second table top  9  ( FIG. 1C ), which is likewise arranged for supporting an object and for being removably mountable to the table  6 . In the shown embodiment the first table top  7  has a first width dimension and a first length dimension, which can hold a A4 or Letter sized object, and the second table top  9  has a second width dimension and a second length dimension, which can hold an A3 sized object. 
     In  FIG. 1D  an object presenting unit  1  is shown with the first table top  7  of  FIG. 1B . As can be seen, a user control input unit  10  comprising a number of control buttons  11  and a button  12  is positioned in the object presenting unit  1 . The user control input unit  10  controls at least part of the operation of the vision enhancing device and is in this embodiment a wireless unit which is removably mounted to the table  6 . For easy access by a user, the user control input unit  10  is accessible in that the table tops  7 , 9  are each provided with a recess  13 ,  14  for docking the user control input unit  10 . The user control input unit is provided with two opposite sides ( 10 A.  10 B) wherein each side is provide with at least one control button  12 ,  12 ′ respectively. and wherein the vision enhancing device is arranged such that the control input unit can be inserted in the recess  13 ,  14  with either the first side directed upwardly, for controlling the at least one button provided on the first side, or with the second side directed upwardly for controlling the buttons provided on the second side. The second side comprises more control buttons  12  than the first side (in this example the first side is provided with one button  12 ). In  FIG. 1D  the control unit is inserted in recess  13  with the first side  10 A directed upwardly. However the control unit can also be inserted in the recess  13  with the second side  10 B directed upwardly, see FIG.  1 D′. Please note that buttons  11  may be deleted. In another embodiment the unit  10  in addition to the plurality of buttons  11  (wherein the unit may also comprise the buttons  12  and/or  12 ′) further comprises at least one button  11 ′ on the backside of the unit, such that upon selection either the front side with the plurality of buttons  11  is directed towards the user position for controlling the buttons  11  ( FIG. 1D ) or the second side with the at least one button  11 ′ is directed toward a user position for controlling the button  11 ′ (FIG.  1 D″) when the unit is positioned in the recess  13 . 
     Please note that if table top  9  is located on the table, than the unit  10  may selectively positioned in the recess  14  as discussed above for recess  13 . In  FIG. 2D  the control unit is inserted in recess  14  with the second side  10 B directed upwardly. However the control unit can also be inserted upside down in the recess  14  with the first side  10 A directed upwardly. Also, as discussed above, the unit can be inserted such that the buttons  11 ′ are directed towards the user position. 
     In  FIG. 2A  an embodiment of a vision enhancing device  15  according to the invention is shown in a rear view in perspective. The vision enhancing device  15  comprises a light sensitive sensor  22  mounted in a single housing  23 , which is mounted to an upstanding stand  16  of the device. The light sensitive sensor  22  can, in use, obtain recording signals of an object placed on a table top which signals are indicative for the text and/or the at least one picture on the object. There exists a direct vision path between the light sensitive sensor and the table if no object is carried by the table. This means for example that no mirror is present between the sensor and the table for capturing an image of an object present on the table. The upstanding stand  16  is attached to the bottom plate  2 . A screen  25  is attached to the stand  16 . The upstanding stand  16  is positioned (almost completely) at a left side L or right side R of the light sensitive sensor if the device  1  is viewed from a user position P in front of the screen  25 . Please note that if the stand is positioned at a left side of the sensor, this does not mean that a relatively small portion  101  of the stand light may be at the right side of the sensor. In the shown embodiment the upstanding stand is C-shaped and comprises a lower horizontal arm  17 , an upstanding arm  18  and a horizontal upper arm  19 . The bottom plate  2  is provided with a channel  20  ( FIG. 4C ) for receiving the lower arm  17  of the C-shaped upstanding stand  16 , such that the stand  16  is displaceably mounted to the bottom plate  2  in a direction from left to right or vice versa (when viewed from the user position P located at a distance (indicated as d in  FIG. 2A ) in front of the screen), which in the shown embodiment is the first direction FD. This direction FD extends in a horizontal plane parallel to the screen. Thus is holds that the upstanding stand is arranged to be positioned at a left or right side of the sensor and/or (a middle of) the screen (when viewed from a position in front of the screen). The screen may be attached to the stand. Thus in that case it holds that the stand is arranged to be positioned on a left side (as shown in  FIG. 2A ) or right side of the sensor (and screen in this example (and a middle of the screen in this example) if the device (and screen in this example) is viewed from a user position in front of the screen if the device screen is attached to the stand. 
     It is noted that in an alternative embodiment the screen may also be positioned on about the same position as indicated in  FIG. 2A , however in that case the screen is not attached to the stand, but is for example attached to a second separate stand  100 , as shown in FIG.  2 A′. Thus in that case it also holds that the stand  16  is arranged to be positioned on a left side (as is shown in FIG.  2 A′) or right side of the sensor and/or screen if the device is viewed from a user position P in front of the screen. In that case the sensor  22  and the housing  23  remain attached to the stand  16  as discussed for  FIG. 2A . 
     As indicated in  FIG. 2A  the vision enhancing device  15  comprises releasable tightening means  21 , e.g. tightening screws, which are arranged for, when tightened fixing the position of the stand  16 , in particular the lower arm  17 , relative to the bottom plate  2  and for, when released, allowing displacement of the stand  16  relative to the bottom plate  2 . 
     The vision enhancing device  15  furthermore comprises a light sensitive sensor  22  mounted in a single housing  23 , which is mounted to the upstanding stand  16 . The light sensitive sensor  22  can, in use, obtain recording signals of an object placed on a table top which signals are indicative for the text and/or the at least one picture on the object. In the shown embodiment the vision enhancing device  15  is provided with processing means  24  for processing the recording signals into video signals, which are supplied to, and can be displayed as an image on, a screen  25  mounted to the upstanding stand  16 . In a preferred embodiment the processing means  24  are located within the housing  23  close to the sensor  22 . In the shown embodiment the processing means  24  is included in the same housing as the screen  25 , but in other embodiments of the invention (not shown) additional processing means can be included in a separate, stand alone personal computer or in the housing that holds the light sensitive sensor. 
     The screen  25  and the sensor  22  are displaceably mounted to the upper arm  19  in the direction FD from left to right or vice versa so that the light sensitive sensor  22  and the screen  25  can be positioned above the bottom plate  2  and in particular above the table top carrying the object. Thus it holds in this example that the screen  25  and the sensor  22  are displaceably mounted to the upper arm  19  in the direction FD from left to right along a straight line or vice versa so that the light sensitive sensor  22  and the screen  25  can be positioned above the bottom plate  2  and in particular above the table top carrying the object. The light sensitive sensor may be positioned by means of the sensor being displaceably mounted to the upper arm and the bottom plate to be displaceably mounted to the lower arm such that the light sensitive sensor is positioned vertically above (see vertical line V in  FIG. 2B ) a middle M (see  FIG. 2B ) of the table top if the middle of the table top is positioned in the middle of all possible positions the middle of the table top can take due to the displaceability of the table relative to the bottom plate. To releasably fix the position of the screen  25  relative to the upper arm  19  and for after releasing allowing displacement of the screen  25  relative to the upper arm  19  releasable tightening means  26 , e.g. tightening screws are provided. In the shown embodiment these tightening screws are positioned in a recess which can be closed by a swivelable cover  27 . 
     According to the invention the upstanding stand  16  is arranged to be positioned at a left or right side of the screen  25 , which is clearly indicated in  FIGS. 2A to 2D . In this manner displacement of the table  6  relative to the bottom plate  2  in combination with displacement of the stand  16  relative to the bottom plate  2  is possible over such a distance that a footprint for a respective table top is obtained that is about twice its surface area thereby making it possible to position any part of the object below the light sensitive sensor for optimal performance of the vision enhancing device. 
     From  FIGS. 2C and 2D  which show the vision enhancing device  15  in a front view in perspective it can be seen that the appearance of the vision enhancing device is furthermore quite attractive (amongst other due to free space availability behind the device and screen) in addition to having a relatively small footprint, which among other things makes it easier to position the vision enhancing device on a desk top. In the collapsed configuration as shown in  FIG. 2   c  for example the table top  7  that can hold an A4 sized object can be used in for example portrait configuration whereas in the expanded configuration shown in  FIG. 2D  for example the table top  9  that can hold an A3 sized object can for example be used in landscape configuration. 
     As mentioned above the vision enhancing device  15  is used for recording an object  28  ( FIGS. 3A and 3B ) whereon text  29  and/or at least one picture  30  are visible and for displaying the recorded object on the screen  25 . For recording the object  28  the light sensitive sensor  22  comprises an overview camera  31  for providing overview recording signals of the object  28 , which signals represent an image of the complete object  28 , to the processing means  24  for processing the overview recording signals such that the complete object  28  is displayed on the screen  25  as indicated in  FIG. 3B  in full lines. Furthermore, the sensor  22  comprises a separate optical zoom camera  32  for, in use, providing enlarged recording signals of the object  28  which signals represent an image of a part  33 ,  34  of the text and/or the at least one picture on the object  28 . The processing means  24  can under user control via the user control input unit  10  display such parts of the text and/or the at least one picture enlarged on the screen  25 . By combining the two separate cameras  31 ,  32  it is possible to extend the optical zoom factor up to e.g. 54× while using standard available, inexpensive cameras. The overview camera  31  provides a full overview of the object  28  on the screen  25  while the optical zoom camera  32 , in the shown embodiment having a zoom range of 18, can provide a zoom factor (=magnification) from e.g. 3× to 54×. For example the optical zoom camera may have a maximum zoom factor (=magnification) in the range of 6-30, preferably 8-20, more preferably 10-18. 
     In the embodiment shown in  FIG. 3B  the processing means  24  is arranged for, in use and upon user input, displaying the overview of the object  28  and the part  33 ,  34  to be enlarged of the object simultaneously, but the user can also choose a mode of operation in which the overview of the object and the enlarged part of the object are displayed alternately or simultaneously. In this manner the user can switch from one camera to the other or simultaneously view the images to quickly find the magnified text on the object. 
     The light sensitive sensor  22  according to the embodiment of  FIG. 3  further comprises a separate OCR-camera  35  for obtaining OCR-recording signals, wherein the OCR-camera is arranged for, in use, providing the OCR-recording signals representing at least a part of the recorded object  28  to the processing means  24  for performing image analysis and/or image processing on the OCR-recording signals. The image analysis and/or the processed images can be displayed on the screen. The OCR-camera preferably has a wide field of vision and a higher resolution (tailored for OCR processing with an optimum between quality and quantity of the amount of processed textual information. Control buttons for operating the OCR-camera and for choosing specific modes of operation, as well as for controlling other functions of the vision enhancing device, can be installed on the user control input unit  10 . 
     With reference to  FIGS. 4 and 5  the construction of the object presenting unit  1 , in particular user operable mechanical brakes will be described in more detail. The object presenting unit of the vision enhancing device according to the invention comprises a first mechanical brake for, upon activation, preventing or providing resistance to displacement of the table  6  in the first direction FD and a user operable second mechanical brake for, upon activation, preventing or providing resistance to displacement of the table  6  in the second direction SD, wherein the mechanical brakes are operable independently from each other to control displacement in the two opposite direction independently from each other. 
     The said first mechanical brake comprises a rigid longitudinal ridge  36  fixed on the bottom table  2  and extends in the first direction FD. Furthermore, the first mechanical brake comprises a first rigid longitudinal ruler  37  which is swivelably mounted on the intermediate mid-table  3  around a swivel axis  37 A ( FIG. 5D ), which extends in the first direction FD, and a plunger  38  that is mounted on the intermediate mid-table  3 . The plunger  38  is—under user control—arranged for being positioned from an idle position to an active position (shown in  FIG. 5D ), in which active position the plunger  38  pushes the ruler  37  against the longitudinal ridge  36 , thus increasing the friction such that displacement of the table in the first direction FD relative to the bottom plate  2  is completely blocked or at least made more difficult. In the idle position (IP), in which the free end of the plunger  38  takes the position indicated by dotted lines, the ruler  37  is free from the longitudinal ridge  36  and thus displacement in the first direction FD is enabled. The first mechanical brake comprises a first eccentric  102  that is rotatable by means of a wheel  39  on the one hand and acts on the plunger  38  on the other hand for displacing the plunger upon rotation of the first control rod. 
     The first eccentric  102  of the first mechanical brake can position the plunger  38  either in the idle position or the active position, which eccentric is rotatable by means of a wheel  39  that is rotatable by a first worm wheel  40  mounted on the intermediate mid-table  3 . The first worm wheel  40  is rotatable by means of a first control rod  41 , which fits into a through hole of the first worm wheel  40 . The first control rod  41  is slidable within the first worm wheel  40  in a direction  1 . A free end of the first rod  41  is provided with a first gear wheel  42 , which is in engagement with a first rack  43  that is slidably attached to the table  6  in a direction parallel to the first direction FD. The first rack  43  is connected to a first handle  44  positioned below the recess of a table top mounted on the table. The first handle  44  is user operable to slide the first rack  43  relative to the table  6  as a result of which the first gear wheel  42  is brought into rotation thereby rotating the first worm wheel  40  and the wheel  39  and the first eccentric  102  to position the plunger  38  in the desired position for either enabling or disabling displacement in the first direction FD. 
     The second mechanical brake comprises a rigid longitudinal brake rod  45  attached to the table  6  and extending in the second direction SD. A brake shoe  46  of the second mechanical brake can—under user control—be positioned in an idle position ( FIG. 5B ) or an active position ( FIG. 5C ). In the active position the brake shoe  46  is in engagement with the longitudinal brake rod  45  preventing displacement in the second direction SD and in the idle position the brake shoe  46  is free from the longitudinal brake rod  45  thereby enabling displacement in the second direction SD. In the shown embodiment the second mechanical brake  46  comprises a brake shoe formed by two translatable brake shoe portions  46 A,  46 B positioned at either side of the longitudinal rod  45 . The translatable brake shoe portions  46 A,  46 B are translatable toward each other and vice versa by means of a rotatable second eccentric  104  that is rotatable by a second worm wheel  47  mounted on the intermediate mid-table  3 . The second worm wheel  47  is rotatable by means of a second control rod  48 , a free end of which is provided with a second gear wheel  49 . The second control rod is slidable within the second worm wheel in the direction  1 . This second gear wheel  49  is in engagement with a second rack  50 , which is slidably attached to the table  6  in a direction parallel to the first direction FD. The second rack  50  is connected to a second handle  51  positioned below the recess of a table top mounted on the table  6 . The second handle  51  is user operable to slide the second rack  50  relative to the table  6 , as a result of which the second gear wheel  49  is brought into rotation thereby rotating the second worm wheel  47 , thereby rotating the second eccentric  104  and thereby translating the brake shoe portions  46 A,  46 B to position the brake shoe portions in the desired position against or away from the brake rod  45  for either enabling or disabling displacement in the second direction SD. 
     It can be seen in  FIG. 5A  that the through hole in the worm wheels  40 ,  47  is polygonal and the shape of the rods  41 ,  48  matches the shape of the holes so that rotation of the rods by rotating the gear wheels is directly transferred to the worm wheels. Thus it holds that the first mechanical brake comprises the wheel  39  arranged for positioning said plunger  38  in the idle position or the active position, said wheel being rotatable by a first worm  40  wheel mounted on the intermediate mid-table, said first worm wheel being rotatable by means of a first control rod  41  wherein the first control rod is slidable along a longitudinal direction of the first control rod within the first worm wheel. Furthermore it holds that the first mechanical brake comprises a first eccentric  102 , which is rotatable by means of the wheel  39  on the one hand, and which acts on the plunger  38  on the other hand, for displacing the plunger upon rotation of the first control rod. A free end of the first control rod is provided with the first gear wheel  42 , which is in engagement with the first rack  43 , which is slidably attached to the table in a direction parallel to the first direction. Said second mechanical brake comprises the rigid longitudinal brake rod  45  attached to the table and extending in the second direction and the brake shoe  46 , which brake shoe is—under user control—arranged for being positioned from an idle position to an active position, in which active position the brake shoe engages the longitudinal brake rod  45  and in which idle position the brake shoe is free from the longitudinal rod. The second mechanical brake comprises a brake shoe formed by two translatable brake shoe portions positioned at either side of the longitudinal brake rod, said rotatable brake shoe portions  46  A,  46 B being translatable relative to each other by the second worm wheel  47  mounted on the intermediate mid-table, said second worm wheel being rotatable by means of the second control rod  48  wherein the second control rod is slidable along a longitudinal direction  1  of the second rod within the second worm wheel. 
     The vision enhancing device is provided with the second eccentric  104 , which is engaged by the second worm wheel on the one hand for rotation of the second eccentric upon rotation of the second worm wheel, and which second eccentric  104  engages the brake shoe portions such that when the second eccentric is rotated by the second worm wheel  47  in a first direction, a distance between the brake shoes is decreased for engaging or more engaging the brake rod and such that if the eccentric is rotated by the worm wheel in a second direction opposite to the first direction, the distance between the brake shoes is increased for disengaging or less engaging the brake rod. The free end of the second control rod is provided with a second gear wheel, which is in engagement with a second rack that is slidably attached to the table in a direction parallel to the first direction. A wheel axle on which the wheel is rotatably mounted, and the axle around which the rotatable first eccentric is rotatably mounted, and the axle around which the rotatable second eccentric is rotatably mounted, coincide with each other (see  FIG. 5F ). The longitudinal brake rod is slidably received in a guiding channel  106  formed by the braking shoes  46 A,  46 B, said guiding channel being mounted on the intermediate mid-table. Said first mechanical brake may further comprise a second rigid longitudinal ruler (not shown) which is swivelably mounted on the intermediate mid-table around a swivel axis which extends in the first direction wherein the plunger is—under user control—arranged for being positioned from an idle position to an active position, in which active position the plunger pushes the first and second ruler against opposite sides of the longitudinal ridge and in which idle position the first and the second ruler are free from the longitudinal ridge. 
     The displacement of the table  6  relative to the intermediate mid-table  3  in the second direction SD is realized in a manner known per se by means of a rail construction  54  ( FIG. 4A  and  FIG. 6B ). In the embodiment shown e.g. in  FIG. 5A  the longitudinal rod  45  extending in the second direction SD is slidably received in a guiding channel  55  mounted on the intermediate mid-table  3 . This guiding channel  55  not only is beneficial for the reproducibility of the displacement of the table  6  in the second direction SD over an extended period of time, but also positions the longitudinal rod  45  correctly with regard to the brake shoe  46 , thereby providing a reliable brake function in the second direction SD. 
     In  FIGS. 6A to 6B  the extreme positions of the table  6  (for clarity reasons without table top) relative to the bottom plate  2  are shown in perspective footprint. From these figures it is clear that the object presenting unit of the vision enhancing device according to the invention is very user friendly, since a user is able to displace an object on the table relative to the bottom plate and thus relative to the light sensitive sensor for obtaining a footprint formed by possible locations of the table which is about twice the surface area of the table thereby enabling recording of all parts of the object.