  Four Stokes parameters (1852) define the polarisation state of light.
Measured changes of the Stokes vector of light traversing an inhomogeneous
sample are linked to the local anisotropies of absorption and refraction and
are harnessed over an increasing range of applications in photonics, material,
and space/earth observation. Several independent polarisation sensitive
measurements are usually required for determination of the all four Stokes
parameters, which makes such characterisation procedure time-consuming or
requires complex setups. Here we introduce a single-snapshot approach to Stokes
polarimetry in transmission by use of a 4-polarisation camera with the on-chip
integrated polarisers. A quarter-waveplate was added in front of the sample and
was illuminated by a linearly polarised light. This approach is demonstrated by
measuring birefringence $\Delta n\sim 0.012$ of spider silk of only $\sim
6~\mu$m-diameter using microscopy, however, due to its generic nature, it is
transferable to other spectral ranges and imaging applications, e.g., imaging
from a fast moving satellite or drone or monitoring fast changing events such
as phase transitions.
