Effect of Contrast and Threshold on Auto-find Performance

The ability of the auto-find feature to detect spots on a single frame is tested with a grid of 25 Gaussian spots on a 400 by 400 pixel image. The Gaussian spots have a standard deviation 5 and maximum value specified to observe the effect of varying contrast levels. For each contrast level, auto-find is tested with varying levels of the fluorescent_spot_threshold setting. These settings and spot types are tested on three different types of backgrounds (flat, gradient, and Gaussian) to observe the effect of a non-uniform background on auto-find performance. The flat background has a brightness of 0.4, the brightness of the gradient background ranges from 0 to 0.6 as a fraction of total brightness, and the Gaussian background consists of a Gaussian spot with maximum value 0.4 and radius 100. The table indicates how many beads out of the possible 25 the Video Spot Tracker detects. For all trials, the Video Spot Tracker maintain_fluorescent_beads option is set at 25, and all other settings are default. All trials use a symmetric tracking kernel with a radius of 13.

Test 1: Flat Background

Example images follow:

gaussian_5_sym_flat.0.5.0_0.0000.bmp	gaussian_5_sym_flat.0.3.0_0.0000.bmp
gaussian_5_sym_flat.0.1.0_0.0000.bmp	gaussian_5_sym_flat.0.05.0_0.0000.bmp

Test 2: Gradient Background

Example images follow:

gaussian_5_sym_gradient.0.5.0_0.0000.bmp	gaussian_5_sym_gradient.0.3.0_0.0000.bmp
gaussian_5_sym_gradient.0.1.0_0.0000.bmp	gaussian_5_sym_gradient.0.05.0_0.0000.bmp

Test 3: Gaussian Background

Example images follow:

gaussian_5_sym_gaussian.0.5.0_0.0000.bmp	gaussian_5_sym_gaussian.0.3.0_0.0000.bmp
gaussian_5_sym_gaussian.0.1.0_0.0000.bmp	gaussian_5_sym_gaussian.0.05.0_0.0000.bmp