Abstract
Cell localization is an important area of medical image analysis, which
is dedicated to predicting the precise location of cells in an image.
The existing localization paradigm is to predict the density map using a
Convolutional Neural Networks (CNN) model based on vanilla convolution
and then process the density map using a local maximum search strategy
to obtain the cell location and number information. However, there are
three main problems in this paradigm: 1) CNN models based on vanilla
convolution have difficulty in handling large variations in cell color;
2) The density map is difficult to provide accurate cell location
information and ideal gradient information, and the information loss is
more obvious in dense regions; 3) The post-processing strategy of
density maps is susceptible to background noise and mutual interference
between negative and positive cells. To tackle the above issues, we have
made a comprehensive update of the existing paradigm, which consists of
three parts: 1) A multi-scale gradient aggregation module based on
difference convolution to effectively mitigate the challenge of large
variations in cell color; 2) A new exponential distance transform map
that provides accurate cell location information along with ideal
gradient information for model learning; 3) A post-processing strategy
named cell center localization strategy based on location maps that can
significantly improve the localization performance. Extensive
experiments on multiple datasets show that our approach can
substantially improve cell localization and counting performance,
establishing a new baseline for the cell localization task, and thereby
increasing the efficiency of computer-aided diagnosis.