magentaMULTI
Keywords: imager

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#### magenta`MULTI`

The Multi-scale `CLEAN` algorithm has also been designed to improve the performance of `CLEAN` for extended sources. It is a straightforward extension of `CLEAN` that models the sky brightness by the summation of blobs of emission having different size scales. It is equivalent to simultaneously deconvolve images obtained with different synthesized beams derived from the highest resolution one by convolution kernels. This algorithms works simultaneously in a range of specified scales. Multi-scale `CLEAN` can produce good images with a loop gain of 0.5 or even higher.

The implementation of Multi-scale `CLEAN` in [rgb]1,0,0IMAGER slightly differs from that of CASAIt is less optimized in terms of speed, but uses a better convergence scheme in which the scale chosen at each iteration is the one with best signal to noise ratio. Accordingly, it is more stable. Only 3 scales are used so far in [rgb]1,0,0IMAGER, with a size ratio controlled by blue`CLEAN_SMOOTH`.