Method and system for velocity-normalized position-based scanning

Abstract

A data collection method for scanning a scan window comprising one or more channels is described. In the method of the invention an integrated signal (S) is measured across a scan window including one or more channels using an integrating detector. Next, a velocity-normalized integrated signal (Sn) is determined based on the integrated signal (S) and a scan velocity.

1. A data collection method for scanning a scan window comprising one or more channels comprising the steps of:
 detecting an integrated signal (S) across a the scan window comprising one or more channels using an integrating detector; and  
 calculating a velocity-normalized integrated signal (Sn) as a function of a scan velocity and the integrated signal S.  
 
     
     
       2. The method of  claim 1  wherein the step of calculating the velocity-normalized integrated signal (Sn) comprises:
 determining a scan velocity, v; and  
 dividing the integrated signal S by the scan velocity v.  
 
     
     
       3. The method of  claim 1  wherein the step of calculating the velocity-normalized integrated signal (Sn) comprises:
 measuring a channel width (w);  
 determining a time for traversing the channel width (t); and  
 computing a the velocity-normalized integrated signal according to the equation Sn=S/(w/t).  
 
     
     
       4. The method of  claim 1  wherein the step of calculating the velocity-normalized integrated signal (Sn) comprises subtracting a detector offset So from an the integrated signal (S). 
     
     
       5. The method of  claim 1  wherein the channels are disposed in a linear array. 
     
     
       6. The method of  claim 1  wherein the channels are lanes in a multilane electrophoresis system. 
     
     
       7. The method of  claim 6  wherein the lanes are located in a slab gel. 
     
     
       8. The method of  claim 6  wherein the lanes are located in isolated electrophoresis channels. 
     
     
       9. The method of  claim 6  wherein the lane density of the multilane electrophoresis system is has a lane density of at least 1.8 mm/lane. 
     
     
       10. The method of  claim 1  wherein the step of detecting an integrated signal across a scan window is effected using a stepper motor to cause a relative motion between the scan window and the integrating detector. 
     
     
       11. The method of  claim 10  wherein a channel width (w) is measured by counting steps in the stepper motor. 
     
     
       12. The method of  claim 11  wherein a position sensor is used to define a home position for initializing the stepper motor. 
     
     
       13. The method of  claim 1  wherein the integrating detector is a CCD or a photodiode array. 
     
     
       14. The method of  claim 1  wherein the integrated signal results from detection of a fluorescence emission. 
     
     
       15. The method of  claim 14  wherein the fluorescence emission is stimulated by a laser. 
     
     
       16. An apparatus for scanning a plurality of channels comprising:
 means for detecting an integrated signal (S) across a scan window comprising one or more the plurality of channels using an integrating detector; and  
 computer means for receiving the integrated signal S and determining a scan velocity and for calculating a velocity-normalized integrated signal (Sn) as a function of the scan velocity and the integrated signal S.  
 
     
     
       17. An apparatus for scanning a scan window having one or more channels comprising:
 an integrating detector;  
 a scanner for effecting a scanning of the integrating detector relative to a the scan window comprising one or more channels, wherein an integrated signal ( S )  is detected by scanning the integrating detector relative to the scan window ; and  
 a computer for receiving the integrated signal S and for determining a scan velocity and for calculating a velocity-normalized integrated signal (Sn).  
 
     
     
       18. The apparatus of  claim 17  wherein the integrating detector is a charged coupled device. 
     
     
       19. The apparatus of  claim 17  wherein the scanner comprises a stepper motor. 
     
     
       20. The apparatus of  claim 17  wherein the scan window comprises multiple electrophoresis lanes. 
     
     
       21. A program storage device readable by a machine, tangibly embodying a program of instructions executable by a machine to perform method steps to scan a scan window comprising one or more channels, said method steps comprising:
 detecting an integrated signal (S) across a scan window comprising one or more channels using an integrating detector; and  
 calculating a velocity-normalized integrated signal (Sn) as a function of a scan velocity and the integrated signal S.  
 
     
     
       22. The program storage device of  claim 21  wherein the step of calculating the velocity-normalized integrated signal (Sn) comprises:
 determining a scan velocity, v; and  
 dividing the integrated signal S by the scan velocity v.  
 
     
     
       23. The program storage device of  claim 21  wherein the step of calculating the velocity-normalized integrated signal (Sn) comprises:
 measuring a channel width (w);  
 determining a time for traversing the channel width (t); and  
 computing a the velocity-normalized integrated signal according to the equation Sn=S/(w/t).  
 
     
     
       24. The program storage device of  claim 21  wherein the step of calculating the velocity-normalized integrated signal (Sn) comprises subtracting a detector offset So from an integrated signal (S). 
     
     
       25. The program storage device of  claim 24  wherein a the channel width (w) is measured by counting steps in the stepper motor. 
     
     
       26. The method of  claim 1 , further comprising determining an integration time ( ti )  for the integrated signal; and      wherein the calculating the velocity - normalized integrated signal comprises dividing the integrated signal  ( S )  by the integration time  ( ti ) ,        and wherein the scan window comprises more than one channel.     
     
     
       27. The method of  claim 26 , wherein determining the integration time ( ti )  comprises determining a start time  ( ts )  at a start of the detecting the integrated signal; determining an end time  ( te )  at an end of the detecting the integrated signal; and determining the integration time  ( ti )  as a difference of the end time  ( te )  and the start time  ( ts ) .   
     
     
       28. The method of  claim 27 , wherein the integrating detector comprises at least one of a CCD and a photodiode array. 
     
     
       29. The apparatus of  claim 16 , furthering comprising means for determining an integration time ( ti )  for the integrated signal; and wherein the calculating the velocity - normalized integrated signal comprises dividing the integrated signal  ( S )  by the integration time  ( ti ) .   
     
     
       30. The apparatus of  claim 29 , wherein determining the integration time ( ti )  comprises determining a start time  ( ts )  at a start of the detecting the integrated signal; determining an end time  ( te )  at an end of the detecting the integrated signal; and determining the integration time  ( ti )  as a difference of the end time  ( te )  and the start time  ( ts ) .   
     
     
       31. The apparatus of  claim 30 , further comprising the integrating detector. 
     
     
       32. The apparatus of  claim 17 , further comprising a timer configured to determine an integration time ( ti )  for the integrated signal; and wherein the calculating the velocity - normalized integrated signal comprises dividing the integrated signal  ( S )  by the integration time  ( ti ) , and the scan window comprises more than one channel.   
     
     
       33. The apparatus of  claim 32 , wherein determining the integration time ( ti )  comprises determining a start time  ( ts )  at a start of the detecting the integrated signal; determining an end time  ( te )  at an end of the detecting the integrated signal; and determining the integration time  ( ti )  as a difference of the end time  ( te )  and the start time  ( ts ) .   
     
     
       34. The program storage device of  claim 21 , wherein the method further comprises determining an integration time ( ti )  for the integrated signal  ( S ) ; the calculating the velocity - normalized integrated signal  ( Sn )  comprises dividing the integrated signal  ( S )  by the integration time  ( ti ) ; and the scan window comprises more than one channel.   
     
     
       35. The program storage device of  claim 34 , wherein determining the integration time ( ti )  comprises determining a start time  ( ts )  at a start of the detecting the integrated signal; determining an end time  ( te )  at an end of the detecting the integrated signal; and determining the integration time  ( ti )  as a difference of the end time  ( te )  and the start time  ( ts ) .   
     
     
       36. An apparatus for scanning one or more channels comprising:
   means for detecting an integrated signal  ( S )  across a scan window comprising one or more channels using an integrating detector; and        computer means for receiving the integrated signal S and determining a scan velocity and for calculating a velocity - normalized integrated signal  ( Sn )  as a function of the scan velocity and the integrated signal S.     
     
     
       37. The apparatus according to  claim 36 , further comprising the integrating detector. 
     
     
       38. A data collection method for scanning a scan window comprising:
   detecting an integrated signal  ( S )  across the scan window comprising one or more channels using an integrating detector;        determining an integration time  ( ti )  for the integrated signal; and        calculating a velocity - normalized integrated signal  ( Sn ) , the calculating comprising dividing the integrated signal  ( S )  by the integration time  ( ti ) .     
     
     
       39. The method of  claim 38 , wherein determining the integration time ( ti )  comprises determining a start time  ( ts )  at a start of the detecting the integrated signal; determining an end time  ( te )  at an end of the detecting the integrated signal; and determining the integration time  ( ti )  as a difference of the end time  ( te )  and the start time  ( ts ) .   
     
     
       40. The method of  claim 39 , further comprising determining a detector offset ( So ) ; determining an offset adjusted unnormalized signal as the difference  ( S−So ) ; and wherein the calculating the velocity - normalized integrated signal  ( Sn )  comprises dividing the offset adjusted unnormalized signal by the integration time  ( ti ) .   
     
     
       41. The method of  claim 40 , wherein determining the offset adjusted unnormalized signal further comprises multiplying the difference ( S−So )  by a scaling factor  ( tn ) .   
     
     
       42. The method of  claim 39 , wherein the channels are disposed in a linear array. 
     
     
       43. The method of  claim 39 , wherein the channels comprise lanes in a multilane electrophoresis system. 
     
     
       44. The method of  claim 43 , wherein the lanes are located in a slab gel. 
     
     
       45. The method of  claim 43 , wherein the lanes are located in isolated electrophoresis channels. 
     
     
       46. The method of  claim 43 , wherein the multilane electrophoresis system has a lane density of at least  1 . 8  mm/lane. 
     
     
       47. The method of  claim 39 , wherein detecting the integrated signal comprises using a stepper motor to cause a relative motion between the scan window and the integrating detector. 
     
     
       48. The method of  claim 47 , wherein a position sensor is used to define a home position for initializing the stepper motor. 
     
     
       49. The method of  claim 39 , wherein the integrating detector comprises at least one of a CCD and a photodiode array. 
     
     
       50. The method of  claim 39 , wherein the integrated signal results from detection of a fluorescence emission. 
     
     
       51. The method of  claim 50 , wherein the fluorescence emission is stimulated by a laser. 
     
     
       52. An apparatus for scanning one or more channels comprising:
   means for detecting an integrated signal  ( S )  across a scan window comprising one or more channels using an integrating detector;        means for determining an integration time  ( ti )  for the integrated signal; and        computer means for receiving the integrated signal  ( S )  and the integration time  ( ti ) , and for determining a velocity - normalized integrated signal  ( Sn ) , the determining comprising dividing the integrated signal  ( S )  by the integration time  ( ti ) .     
     
     
       53. The apparatus of  claim 52 , wherein determining the integration time ( ti )  comprises determining a start time  ( ts )  at a start of the detecting the integrated signal; determining an end time  ( te )  at an end of the detecting the integrated signal; and determining the integration time  ( ti )  as a difference of the end time  ( te )  and the start time  ( ts ) .   
     
     
       54. The apparatus of  claim 53 , wherein the computer means comprises the means for determining the integration time ( ti ) .   
     
     
       55. The apparatus of  claim 53 , further comprising the integrating detector. 
     
     
       56. An apparatus for scanning a scan window having one or more channels comprising:
   an integrating detector;        a scanner configured to scan the integrating detector relative to the scan window, wherein an integrated signal  ( S )  is detected by scanning the integrating detector relative to the scan window;        a timer configured to determine an integration time  ( ti )  for the integrated signal; and        a computer configured to receive the integrated signal  ( S )  and the integration time  ( ti ) , and to determine a velocity - normalized integrated signal  ( Sn ) , the determining comprising dividing the integrated signal  ( S )  by the integration time  ( ti ) .     
     
     
       57. The apparatus of  claim 56 , wherein determining the integration time ( ti )  comprises determining a start time  ( ts )  at a start of the detecting the integrated signal; determining an end time  ( te )  at an end of the detecting the integrated signal; and determining the integration time  ( ti )  as a difference of the end time  ( te )  and the start time  ( ts ) .   
     
     
       58. The apparatus of  claim 57 , wherein the computer is configured to determine the integration time ( ti ) .   
     
     
       59. The apparatus of  claim 57 , wherein the integrating detector comprises a charged coupled device. 
     
     
       60. The apparatus of  claim 57 , wherein the scanner comprises a stepper motor. 
     
     
       61. The apparatus of  claim 57 , wherein the scan window comprises multiple electrophoresis lanes. 
     
     
       62. A program storage device readable by a machine, tangibly embodying a program of instructions executable by a machine to perform a method to scan a scan window comprising one or more channels, said method comprising:
   detecting an integrated signal  ( S )  across a scan window comprising one or more channels using an integrating detector;        determining an integration time  ( ti )  for the integrated signal  ( S ) ; and        calculating a velocity - normalized integrated signal  ( Sn ) , the calculating comprising dividing the integrated signal  ( S )  by the integration time  ( ti ) .     
     
     
       63. The program storage device of  claim 62 , wherein determining the integration time ( ti )  comprises determining a start time  ( ts )  at a start of the detecting the integrated signal; determining an end time  ( te )  at an end of the detecting the integrated signal; and determining the integration time  ( ti )  as a difference of the end time  ( te )  and the start time  ( ts ) .   
     
     
       64. The program storage device of  claim 63 , wherein the method further comprises determining a detector offset ( So ) ; determining an offset adjusted unnormalized signal as the difference  ( S−So ) ; and wherein the calculating the velocity - normalized integrated signal  ( Sn )  comprises dividing the offset adjusted unnormalized signal by the integration time  ( ti ) .   
     
     
       65. The program storage device of  claim 64 , wherein determining the offset adjusted unnormalized signal further comprises multiplying the difference ( S−So )  by a scaling factor  ( tn ) .