Bats can navigate through foliage thanks to their biosonar. To build an image of their environment they emit ultrasonic pulses and analyse the corresponding echo signals which consist of a complex superposition of a set of highly overlapping reflected pulses coming from the targets at their different positions. We propose to use a sparse representation of echoes in overcomplete dictionaries to perform 3D imaging using biosonar signals. We show that even if the echosignal is a superposition of highly overlapping echoes the algorithm can efficiently reconstruct the image only from a single measurement. Those results can be useful from a robot sensor perspective where the robot has to find a free path. It can also help to understand better how bats can efficiently navigate through dense foliage.