Abstract: According to an aspect, there is provided a method for minimising error in ambient light corrected (ALC) images due to motion.

Abstract: According to an aspect, there is provided a method for minimising error in ambient light corrected image due to motion, the method comprising: capturing a plurality of primary images with controlled intensity of illumination varying over time, estimating an error value due to motion for each of a plurality of sub-sets of the plurality of primary images, and performing ambient light correction on an error minimised sub-set of primary images having the lowest estimated error value to generate an ambient light corrected (ALC) image with a minimised error.

Abstract: According to an aspect, there is provided a method for analysing an object, the method comprising illuminating the object with illumination provided by at least two illumination sources, each illumination source being defined by at least one distinct characteristic property; temporally modulating the illumination provided by each illumination source according to a modulation function; capturing a plurality of image frames representing the object using a rolling shutter image sensor; and demultiplexing the plurality of image frames into component images each representing the object under illumination from a respective illumination source, and an ambient image representing the object under an ambient light condition.

Abstract: According to an aspect, there is provided a system (200) comprising: an image projection unit (210) configured to project an illumination pattern onto at least a portion of a scene, an imaging unit (220) configured to capture a plurality of images of the scene while the illumination pattern is projected onto the scene, and a processing unit (230) configured to: demodulate the plurality of images based on the illumination pattern and with respect to a target section in the plurality of captured images, wherein the target section corresponds to one of: a portion of the scene on which the illumination pattern is selectively projected while the plurality of images were captured, a portion of the scene at which the projected illumination pattern is resolvable, a portion of the scene with pixel depth values which satisfy a predetermined range; and generate an ambient light suppressed image of the scene based on results of the demodulation.

Abstract: In an embodiment, a method (100) is described. The method includes accessing (102) data from a sequence of images of a subject illuminated with ambient light and illumination having a sinusoidal intensity modulation in time. An imaging device is used to obtain the sequence of images and is configured such that a different spatial intensity modulation pattern is apparent in consecutive images of the sequence. The method further includes determining (104), based on a set of measured pixel intensity values in each of the sequence of images, a set of revised pixel intensity values for generating a revised image of the subject such that a reduced level of ambient lighting is apparent in the revised image compared with the level of ambient lighting apparent in at least one of the sequence of images.

Abstract: In an embodiment, a method (100) is described. The method is a computer-implemented method. The method comprises receiving (102) pixel information corresponding to at least part of a first, second and third image, acquired by an imaging system, of a subject illuminated by temporally modulated illumination. A time delay between an acquisition start time of the first, second and third images is such that there is an overlap in time during acquisition of the first, second and third images. The method further comprises determining (104) modified pixel information for constructing a modified image of the subject. The modified pixel information is determined based on: a difference between the received pixel information of the first, second and third images to reduce an effect of ambient lighting in the received pixel information; and a combination of the received pixel information to cancel out a spatial intensity modulation pattern apparent in each of the first, second and third images.

Abstract: According to an aspect, there is provided a system (200) comprising: an image projection unit (210) configured to project an illumination pattern onto at least a portion of a scene, an imaging unit (220) configured to capture a plurality of images of the scene while the illumination pattern is projected onto the scene, and a processing unit (230) configured to: demodulate the plurality of images based on the illumination pattern and with respect to a target section in the plurality of captured images, wherein the target section corresponds to one of: a portion of the scene on which the illumination pattern is selectively projected while the plurality of images were captured, a portion of the scene at which the projected illumination pattern is resolvable, a portion of the scene with pixel depth values which satisfy a predetermined range; and generate an ambient light supressed image of the scene based on results of the demodulation.

Abstract: In an embodiment, a method (100) is described. The method includes accessing (102) data from a sequence of images of a subject illuminated with ambient light and illumination having a sinusoidal intensity modulation in time. An imaging device is used to obtain the sequence of images and is configured such that a different spatial intensity modulation pattern is apparent in consecutive images of the sequence. The method further includes determining (104), based on a set of measured pixel intensity values in each of the sequence of images, a set of revised pixel intensity values for generating a revised image of the subject such that a reduced level of ambient lighting is apparent in the revised image compared with the level of ambient lighting apparent in at least one of the sequence of images.

Abstract: Methods and systems for measuring hemoglobin concentration (cHb). A retinal tissue having blood vessels is illuminated by light including two isosbestic wavelengths (?1,?2). The isosbestic wavelengths(?1,?2) correspond to isosbestic points where oxy- and deoxyhemoglobin (HbIO2,Hb) have the same molar extinction coefficient. Measurements are collected of a plurality of backscattered reflection intensities (I(?b,?1), I(xt,?1), I(?b,?2), I(xx,X2)). Preferably, the measurements are spectrally resolved at least for the two isosbestic wavelengths (?1,?2) and position-resolved for at least a blood vessel location (xb) coinciding with a selected blood vessel and a tissue location (xt) coinciding with the retinal tissue without blood vessel. The hemoglobin concentration (cHb) can be calculated based on a combination of the measurements at the two isosbestic wavelengths (?t,?2).