Method and unit for selecting and separating reams from a stack of sheets of paper or similar materials

Abstract

A ream is selected and separated from a stack of sheets by a separating member which is inserted into the stack at an insertion region defined by images acquired by a television camera moved vertically to cover a given scanning region of the stack. In some embodiments, a focused portion of each image acquired by the television camera is located as a function of the location in the image of a line projected onto the stack at an angle of incidence of other than 90°.

1 . A unit for selecting and separating reams from a stack of sheets of paper or similar; the stack comprising a number of sheets stacked in a given direction, and having a front face substantially parallel to said direction; the unit comprising a television camera facing the front face to acquire an image of a portion of the front face; actuating means for moving the stack and the television camera with respect to each other to vary the portion of the front face covered by the television camera; separating means which are inserted inside the stack at a given insertion region to separate a ream from the stack; and control means for counting a number of sheets in the portion of the front face covered by the television camera, and for controlling movement of the insertion region in said direction as a function of the number of sheets counted by means of the images acquired by the television camera; the unit being characterized by comprising an identification device for determining a focused portion of each image acquired by the television camera; the control means modifying the analysis of the image, by which to count the sheets, as a function of the location of said focused portion in the image.  
   
   
       2 . A unit as claimed in  claim 1 , wherein the identification device comprises a linear pointing device for projecting onto the front face of the stack a line striking the front face at an angle of other than 90°; the control means analysing the images acquired by the television camera to locate the projected line in each image, and modifying the analysis of the image, by which to count the sheets, as a function of the location of the projected line in the image.  
   
   
       3 . A unit as claimed in  claim 2 , wherein, for each image acquired by the television camera, the control means determine the focused portion of the image as a function of the location of the projected line in the image, and simply analyse the focused portion.  
   
   
       4 . A unit as claimed in  claim 2 , wherein, for each image acquired by the television camera, the control means determine a distance of the relative sheet from the television camera as a function of the location of the projected line in the image.  
   
   
       5 . A unit as claimed in  claim 1 , wherein the identification device comprises a recognition algorithm for determining a focused portion of each image acquired by the television camera.  
   
   
       6 . A unit as claimed in  claim 1 , wherein the television camera has an optical axis at a further angle of other than 90° with respect to said front face.  
   
   
       7 . A method of selecting and separating reams from a stack of sheets of paper or similar; the stack comprising a number of sheets stacked in a given direction, and having a front face substantially parallel to said direction; the method comprising the steps of acquiring an image of a portion of the front face by means of a television camera facing the front face; moving the stack and the television camera with respect to each other to vary the portion of the front face covered by the television camera; separating a ream from the stack at a given insertion region; counting a number of sheets in the portion of the front face covered by the television camera; and controlling movement of the insertion region in said direction as a function of the number of sheets counted by means of the images acquired by the television camera; the method being characterized by also comprising the steps of determining a focused portion of each image acquired by the television camera; and modifying the analysis of the image, by which to count the sheets, as a function of the location of said focused portion in the image.  
   
   
       8 . A method as claimed in  claim 7 , and comprising the steps of projecting onto the front face of the stack a line striking the front face at an angle of other than 90°; analysing the images acquired by the television camera to locate the projected line in each image; and modifying the analysis of the image, by which to count the sheets, as a function of the location of the projected line in the image.  
   
   
       9 . A method as claimed in  claim 8 , and also comprising the steps of determining, for each image acquired by the television camera, the focused portion of the image as a function of the location of the projected line in the image; and simply analysing the focused portion.  
   
   
       10 . A method as claimed in  claim 8 , and also comprising the step of determining, for each image acquired by the television camera, a distance of the relative sheet from the television camera as a function of the location of the projected line in the image.  
   
   
       11 . A method as claimed in  claim 7 , wherein the focused portion of each image acquired by the television camera is determined by a recognition algorithm.  
   
   
       12 . A unit for selecting and separating reams from a stack of sheets of paper or similar material, the stack comprising a plurality of sheets stacked in a predetermined direction and having a front face substantially parallel to the predetermined direction, the unit comprising: 
 a television camera facing the front face capable of acquiring an image of a portion of the front face;    an actuator for moving the stack and the television camera with respect to each other to vary the portion of the front face covered by the television camera;    a separating member capable of being inserted into the stack at a predetermined insertion region to separate a ream from the stack; and    a controller for counting a number of sheets in the portion of the front face covered by the television camera and for controlling movement of the insertion region in the predetermined direction according to a function of the number of sheets counted by images acquired by the television camera, wherein the unit includes an identification device that determines a focused portion of each image acquired by the television camera and the controller modifies the analysis of the image to count the sheets as a function of the location of the focused portion of the image.