testing
automative cameras or other significantly distorted cameras.
This large chart is designed to be reflectively lit, and captured at a
an optimal focus distance.
Options
include:
- Pre-distortion: Most
automotive camera modules have significant fisheye distortion which can
make it difficult to the outside of the image field. this chart has
pincussion pre-distortion to approximately compensate for the barrel
distiortion of the automotive camera module. The distortion
coefficients that should be entered into the SFRplus settings
window are [1.167 1.577]
- Square
Grid: 5x7 slanted square grid
- Substrate
& ink type: Matte paper & ink can be used to
reduce reflected light. This is critical for high levels of
distiortion, otherwise specular reflections can ruin MTF measurements
- Contrast
levels: 10:1 contrast ratio, common for several automative
testing standards
- Color
chart: a 20 patch color chart for color accuracy and bayer
filter position verification
- Bar
to Bar height: the maximum bar to bar height is 38.5
inches on the left and right side. The minimum bar to bar
height is 23.5 inches in the center.
- Active
Area: the extra-large chart be used for sensor sizes above 24
MP. This chart has an active area of 1500mm x 965mm and is printed on
1117 mm X 1524 mm inch paper
The
active area of the chart includes white space above and below the top
and bottom distortion bars. It is slightly larger than the printed
area, which is bounded by the distortion bars on top and bottom. White
space is included in active area because test images of the chart must
include this white space in order to enable automated processing in
SFRplus software.