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SIGGRAPH 2006 · Detailed comparison

Short, Traditional, and Coded Exposure Compared

01

Exposure timing

Short-exposure timing.
Short-exposure timing.
Traditional continuous-exposure timing.
Traditional continuous-exposure timing.
Coded-exposure timing.
Coded-exposure timing.

A traditional shutter stays open throughout the exposure. A coded shutter follows a binary pseudo-random sequence within a single exposure. The sequence maximizes the minimum DFT magnitude; the broad-band PSF avoids the spectral zeros of a box exposure.

02

Captured images

Short exposure · 4 ms.
Short exposure · 4 ms.
Traditional exposure · 50 ms.
Traditional exposure · 50 ms.
Coded exposure · 50 ms.
Coded exposure · 50 ms.

03

Reconstructed images

Traditional exposure · linear deconvolution.
Traditional exposure · linear deconvolution.
Coded exposure · linear deconvolution.
Coded exposure · linear deconvolution.
Traditional exposure · Richardson–Lucy reconstruction.
Traditional exposure · Richardson–Lucy reconstruction.
Ground-truth static image, captured separately.
Ground-truth static image, captured separately.

Traditional exposure produces a continuous smear; coded exposure produces separated replicas while retaining high spatial frequencies. The coded linear-system result avoids the noise and banding of conventional inversion. Richardson–Lucy reduces noise but smooths the image and reduces sharpness.

04

Output noise covariance

Traditional camera · output noise covariance.
Traditional camera · output noise covariance.
Coded exposure · output noise covariance.
Coded exposure · output noise covariance.

For a representative object 300 pixels wide with 52 pixels of horizontal blur and Gaussian input noise, the output covariance is proportional to (AᵀA)⁻¹ for Ax = b. Conventional blur has large diagonal and off-diagonal entries; coded exposure substantially reduces the off-diagonal entries.

The maximum covariance value is 9270.9 for traditional exposure, corresponding to 39.67 dB noise amplification, versus 77.6 and 18.9 dB for coded exposure.