Bio-rad Laboratories, Inc.

Craig Van Horn

David M Heffelfinger

A method and apparatus for achieving uniform illumination in an electrophoresis apparatus is provided. Uniform illumination allows quantitative measurements of an electrophoresis gel to be made, thus increasing the information which can be obtained from an electrophoretic analysis. Uniform illumination is achieved by scanning the light source, preferably in a trans-illumination mode, across the sample gel in a direction perpendicular to the axis of the source. The light source is comprised of one or more light bulbs placed in a light tray. Variations in light intensity near the source end portions may be minimized using a variety of techniques including extended light bulbs, filters, reflectors, diffusers, or supplemental sources.

Method and apparatus for correcting illumination non-uniformities

A method and apparatus for correcting non-uniformities in the source and the lens assembly of an electrophoresis apparatus is provided. Assuming a detector with a uniform responsivity, correcting for source and lens non-uniformities allows quantitative measurements of an electrophoresis gel to be made, thus increasing the information which can be obtained from an electrophoretic analysis. The non-uniformities due to the illumination source are characterized by sampling a portion of the source with a linear detector array and creating a correction data file. In order to sample the source, a mirror or beamsplitter is appropriately positioned, for example along the central optical axis of the electrophoresis apparatus. Similarly, a correction data file representing the non-uniformities due to the lens assembly is created using a secondary linear source of known uniformity. After the correction data files are stored, an image of the sample is taken and a sample data file is created. The sample data file can be normalized using the correction data files thereby creating a corrected sample file which can either be displayed or stored for future use.

Method and apparatus for the removal of non-uniformities in an

A method and apparatus for correcting non-uniformities in the lens assembly of an electrophoresis apparatus is provided. Assuming a detector with a uniform responsivity as well as a uniform illumination source, correcting for lens non-uniformities allows accurate quantitative measurements of an electrophoresis gel to be made, thus increasing the information which can be obtained from an electrophoretic analysis. Applying the system, the non-uniformities due to the lens assembly are first characterized for a range of aperture and magnification settings. A look-up table is then created which contains the non-uniformities and/or correction data files for the lens assembly according to the aperture and magnification settings. In order to correct a sample image, the aperture and magnification settings used to obtain the sample image are provided to the system processor. These settings may be automatically obtained by the processor or manually input by the user. After the processor receives the lens settings, it applies the look-up table to determine the corresponding lens non-uniformities as well as the necessary correction file. The sample image is then normalized by dividing the sample image file by the appropriate correction file. Once normalized, the corrected sample image file may either be displayed or stored for later use.

Method and apparatus for correcting lens non-uniformities in an

A method and apparatus for correcting an image of an electrophoresis gel for lens and detector non-uniformities is provided. The removal of such non-uniformities, in conjunction with a uniform illumination source, allows quantitative measurements of an electrophoresis gel to be made, thus increasing the information which can be obtained from an electrophoretic analysis. Lens and detector non-uniformities are removed by first determining the magnitude of the non-uniformities using a calibration standard. The calibration standard has a uniform emittance, preferably in the same wavelength band as the labeled regions of the electrophoresis gel. By placing the calibration standard in close proximity to the entrance aperture of the lens, the calibration process is relatively insensitive to illumination source non-uniformities. Thus an image of the calibration standard taken with the same lens settings as the unknown provides detailed information on the lens and detector non-uniformities. This information in conjunction with a darkfield image is used to correct the sample image.

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Sebastapol, CA, United States of America

Craig Van Horn