Color Uniformity

Uniformity measurement interface can be accessed through Uniformity tab. The capture buttons (DevWare Image and Load Image) are on the top. The loaded chart image is displayed on the left (Chart Image group), and the results are displayed on the right (Uniformity Chart group). Test results are displayed below.

Uniformity measurement uses the flat field chart. An image captured in flat field with even (diffused) lighting is needed or it can be captured in DevWare through IQWare interface.

Basic Uniformity Measurement Steps

Basic measurement can be performed following these steps:

• Load the image to be measured using one of the two ways below.

  • Capture from DevWare by clicking the DevWare Image button, DevWare is loaded and the following Setup Sensor dialog will show. DevWare settings might need adjustments to get proper streaming data. Compose the scene with a Macbeth Chart at the front of camera. Once the scene is composed in DevWare, press the OK button in the Setup Sensor dialog. The dialog will disappear and the DevWare image will be captured and loaded in IQWare. (Please note that once DevWare is running, the Setup Sensor dialog will not be prompted again. Image capturing is done by clicking the DevWare Image button again.)
    

  • Load existing image file by clicking the Load Image button. A file dialog will be promopted to browse and select the image file for measurement.

• The uniformity chart with default settings will be displayed on the right. The x axis (bottom) and y axis (left) present the positions of the sub sampled image. The color map on the right represent the range of image intensities. When putting cursor over the uniformity chart, the cursor position in the sub sampled image, original image, and the intensity value will be displayed. Mouse left click sets the zoom in range and right click zooms out.

  

   

  • Sub sample

    Sub sampling is recommended for uniformity test to reduce the affects of hot pixels and dead pixels. The position of the sub sampled image is shown on the x, y axis. They corresponding position in original size image can be found by putting the cursor over the point of interest. The value of each point is color coded for better visual perception.

  • Channel

    Luminance channel Y and color channel R, G, B.

  • Show Contour

    Check box show or head contour of uniformity chart.

  • Low, Step Size, High

    Start, step size, and end of contour line range.

  • Color Map

    There are three different types of color map (stand, gray, jet) for user to select. The color map and value range is displayed on the right side of the Uniformity Chart.

• The loaded image is overlayed by the center and corner regions in use and with respective statics information mean, drop-off value and drop-off percentile from the center. The regions can be adjusted by changing the center and corner percentage.Adjust Center % and Corner % parameters to see real time changes in output. In CPIQ mode, the image is overlayed by CPIQ regions

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• CPIQ (Camera Phone Image Quality Initiative)

  Enable the view of CPIQ regions. CPIQ based shading balance parameters are reported in the result page.
  

• Select the images for the report using the check boxes in the Report group, select the image size in the report by clicking S, M, or L radio button. And then click the Generate Report button to produce the report. User can toggle on/off the check box and click Generate Report button again to produce a new report.

   

• Click the Save to HTML report (Short cut: Ctrl + S) menu under Save button on the top left corner to save the measurements and result chart to selected destination.