Lens-less Imaging Through Incoherent Illumination

The lens-less technique will be evaluated to obtain high resolution images. LED followed by a USAF resolution chart as a mask, sample and detector respectively in a column. The sample info collected by the detector directly without any objective lens. Drawbacks of the lens-less microscopy i.e. twin image and signal to noise ratio will be addressed properly to obtain high resolution image. The sample information will be encoded by the mask at sensor plane during reconstruction process. To retrieve the sample information from captured raw images corresponding to LED illumination, the backward propagation model is applied. According to this model, each image is backward propagated to the sample plane with updating their amplitude. The field is then propagated to the mask plane with the updating free space propagation factor and finally the updated version of sample is obtained using stochastic gradient descent method. Three types of masks will be used phase, amplitude and combination of both with random distribution. The reconstruction process of the sample information will help to reconstruct not only the amplitude but the phase of the sample as well. The application of such type of technique is most commonly in biomedical engineering for infection diagnostic purpose.