You can run object detection on an image of any size, but the quality of the results depends on both the size of the image and the size of the object within the image.
The size of the object within the image is the more important factor: the algorithm works reliably (depending on other factors) if the object occupies a minimum area of 100x100 pixels. Some objects are detectable down to 50x50 pixels. Image Server does not usually detect an object below this size. The maximum object size that Image Server can detect depends on the value of the ClutteredBackground
parameter: if set to False
, the maximum size is unlimited; if set to True
, the maximum size is about 200,000x200,000 pixels (however, an image of this size would run extremely slowly).
The size of the image is less important than the size of the object; however a large image might contain a large amount of clutter, which makes the algorithm slower and increases the false positive rate.
Other than size, factors that can reduce detection accuracy are:
heavy blurring
severe compression artifacts
large amounts of noise
specular lighting effects
very dim lighting
saturated lighting
shadows
occlusion
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