Temperature Drift And Its Compensation Of The Focal Plane In The TDI-fMOST Imaging System

The brain is one of the most complex biological tissue system,humans have been exploring the working mechanism of the brain for over 100 years.The structural and functional connections of the brain neural network play crucial roles in the brain.So,studying the neural anatomies,projections and connections is of great significance to our neuroscience research.Our laboratory had developed a time delay integration CCD based fluorescence microoptical sectioning tomography(TDI-fMOST)system,through the combination with chemical sectioning(CS)method could enable the capturing of complete neural structural image dataset at sub-micron resolution in 7 days.To ensure sub-micron resolution,a high numerical aperture objective was used which has 1.0 ?m depth of field.Since the CS method only chemically active the sample superficial layer with a thickness of about 1.0 ?m.In order to obtain continuous high-resolution whole-brain data,how to long-timely sustain the matching of objective focal plane with CS activation layer within ±0.5 ?m accuracy is a big challenge.But the initial design of TDI-fMOST system couldn't stable the matching for this problem.The temperature would change strikingly over days of imaging,this sign will cause the objective focal plane shifts frequently away from the CS activation layer(temperature drift).The problem of temperature drift would make the detected images blur,then laborious and frequent focal plane readjusting will be needed over days by experienced researchers.This article first systematically studied how the temperature change of TDI-fMOST system affects the position of the imaging focal plane by various components.Based on this,a temperature compensation strategy is proposed.We take the temperature of objective interface as reference to readjust the temperature of objective so as to stabilize the imaging focal plane.Eventually,through circuit,mechanical and software design,with STM32 as the core control device,combined with PID constant temperature algorithm,a temperature compensated constant-focal system was developed.The experimental results show that in the long-term work,the temperature compensated constant-focal system can stabilize the focal plane of the imaging system± 0.5 ?m accuracy,which improves the stability of long time sample detection and meets the experimental requirements.This temperature compensated constant-focal device is an important part of the existing TDI-fMOST imaging system,and has been successfully used on various whole-brain sample imaging processes.