Advantages
- As it does not require a complex optical system or reference light, it is expected to be smaller and less expensive.
- It can provide detailed quantitative information that was not possible with conventional phase contrast microscopes.
- It can also be combined with machine learning, and further cost cuts are also expected through faster processing.
Technology Overview & Background
Conventionally, phase contrast microscopes have been widely used to observe transparent biological samples and other objects with high precision. However, the information obtained using phase contrast microscopes is limited, and it is insufficient for obtaining detailed quantitative data on the object. There have also been reports of quantitative data being obtained by combining phase contrast microscopy with structured illumination to restore images, but there were issues with the large amount of noise and the coarse information obtained. On the other hand, digital holography can acquire quantitative data, but it requires reference light, the optical system is complex, the equipment is large, and it requires multiple images. So it is not suitable for observing dynamic objects.
In response to these issues, the researcher has developed an innovative imaging method that can obtain high-resolution, quantitative information in a single-shot imaging process for both dynamic and static objects, and named this method SPIRaL (single-shot phase imaging with randomized light). Specifically, SPIRaL first irradiates the object with coherent or partially coherent light (random pattern structured illumination) that has interference ability to spatially randomize the amplitude. By performing image processing such as Fourier transform or wavelet transform on the image obtained from the intensity information of the light that has passed through the object after being illuminated with this light, it has become possible to reconstruct the complex amplitude (both amplitude and phase) of the object. This process uses information about the sparseness of the object and information about the light that was irradiated. Unlike reference light, this system does not require complex and large equipment, and quantitative data acquisition of phase and amplitude of dynamic objects such as biological samples can be realized with a compact device and at low cost. It is also possible to combine machine learning with sparseness, in which case reconstruction is not required and high-speed processing is possible. Using this SPIRaL technology, it is possible to obtain numerical data such as cell thickness and refractive index, which are said to be potential indicators for determining whether a cell has become cancerous.
Data
- Phase observation of the oil-water mixture (not emulsion) on the glass plate by SPIRaL confirmed that the shape is equivalent to the image obtained by optical microscopy, and furthermore, the intensity and phase images can be recovered.
- When wires (opaque) were observed by SPIRaL, image recovery was possible with a spatial resolution of at least 30 µm.
Publication(s)
Horisaki R., et. al., Optics Express (2016) 24(4), 3765-3773.
(doi) https://doi.org/10.1364/OE.24.003765
Patent
PCT/JP2017/029156
Patent issued in China, Germany, France, Italy, Japan, UK and US.
Licensable by Osaka University.
Researchers & Academic Institution
Ryoichi Horisaki, PhD (Associate Professor, Tokyo University, Japan)
Expectations
TECH MANAGE is currently looking for microscope manufacturers and various imaging equipment companies to work with researchers to further develop this technology based on the licensing of the above related patents. In addition, joint research using this invention, provision of know-how under a confidentiality agreement (CDA), and evaluation and licensing options can also be considered.
Project.JT-01647