Time stretch imaging with optical data compression for label-free biological cell classification

Real-time instruments that acquire large data sets are needed for detection and classification of outliers. A new class of high throughput real-time instruments based on the photonic time-stretch has led to the discovery of optical rogue waves [1], detection of rare cancer cells [2], and the highest analog-to-digital conversion performance ever achieved [3]. One example of these instruments is the time stretch camera, an imaging modality that features continuous operation at about 100 million frames per second and shutter speed of less than a nanosecond. As an imaging flow-through microscope, the technology is in clinical testing for blood screening. While highly useful for collecting large data sets, the instrument's ultrahigh throughput also creates a big data problem. The system produces a large volume of data in a short time equivalent to several 4K movies per second. Such a data fire hose places a burden on data acquisition, storage, and processing operations and calls for technologies that compress images in optical domain and in real-time. An example of this, based on warped stretch transformation and non-uniform Fourier domain sampling has recently been reported [4]. The paper will provide an overview of the time-stretch microscope with real-time optical image compression, and application of this technology in classification of cancer cell lines in blood.