Camera Adapter Based Optical Imaging Apparatus
First Claim
1. A camera adapter for imaging an object in cooperation with a digital camera with an optical illumination source, a camera sensor, and a shutter release, the camera adapter comprising:
- a light input for accepting light from the optical illumination source;
a light output for directing light onto the camera sensor;
an object facing interface for directing light to the object and back from the object into the adapter;
means in the camera adapter for directing light from the optical illumination source received at the light input to illuminate the object via the object facing interface;
means in the camera adapter for directing light from the object received at the object facing interface onto the camera sensor via the light output; and
means for processing at least one image captured by the camera sensor to generate depth resolved information from the object.
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Abstract
The invention describes several embodiments of an adapter which can make use of the devices in any commercially available digital cameras to accomplish different functions, such as a fundus camera, as a microscope or as an en-face optical coherence tomography (OCT) to produce constant depth OCT images or as a Fourier domain (channelled spectrum) optical coherence tomography to produce a reflectivity profile in the depth of an object or cross section OCT images, or depth resolved volumes. The invention admits addition of confocal detection and provides simultaneous measurements or imaging in at least two channels, confocal and OCT, where the confocal channel provides an en-face image simultaneous with the acquisition of OCT cross sections, to guide the acquisition as well as to be used subsequently in the visualisation of OCT images. Different technical solutions are provided for the assembly of one or two digital cameras which together with such adapters lead to modular and portable high resolution imaging systems which can accomplish various functions with a minimum of extra components while adapting the elements in the digital camera. The cost of such adapters is comparable with that of commercial digital cameras, i.e. the total cost of such assemblies of commercially digital cameras and dedicated adapters to accomplish high resolution imaging are at a fraction of the cost of dedicated stand alone instruments. Embodiments and methods are presented to employ colour cameras and their associated optical sources to deliver simultaneous signals using their colour sensor parts to provide spectroscopic information, phase shifting inferometry in one step, depth range extension, polarisation, angular measurements and spectroscopic Fourier domain (channelled spectrum) optical coherence tomography in as many spectral bands simultaneously as the number of colour parts of the photodetector sensor in the digital camera. In conjunction with simultaneous acquistion of a confocal image, at least 4 channels can simultaneously be provided using the three color parts of conventional color cameras to deliver three OCT images in addition to the confocal image.
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Citations
29 Claims
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1. A camera adapter for imaging an object in cooperation with a digital camera with an optical illumination source, a camera sensor, and a shutter release, the camera adapter comprising:
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a light input for accepting light from the optical illumination source; a light output for directing light onto the camera sensor; an object facing interface for directing light to the object and back from the object into the adapter; means in the camera adapter for directing light from the optical illumination source received at the light input to illuminate the object via the object facing interface; means in the camera adapter for directing light from the object received at the object facing interface onto the camera sensor via the light output; and means for processing at least one image captured by the camera sensor to generate depth resolved information from the object. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 16, 22, 23, 24, 25, 26, 27)
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15. A camera adapter for fundus imaging a retina in cooperation with a digital camera with an optical illumination source, a camera sensor, and a shutter release, the camera adapter comprising:
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a light input for accepting light from the optical illumination source; a light output for directing light onto the photodetector array; an object facing interface for directing light to the retina and back from the retina into the adapter; means in the camera adapter for directing light from the optical illumination source received at the light input to illuminate the retina via the object facing interface; an wavelength filter and a spatial filter in the optical path from the optical illumination source to the object facing interface; means in the camera adapter for directing light from the retina received at the object facing interface onto the camera sensor via the light output; and means for processing at least one image captured by the camera sensor.
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17. Apparatus for imaging an object providing simultaneous measurement in two channels, a confocal channel and an optical coherence tomography (OCT) channel, comprising:
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an optical illumination source, a camera sensor, a main splitter and a 2nd splitter an optical dispersion element dispersing light as a function of wavelength, placed in the light path between one of the output of the 2nd splitter and the said adapter output a confocal receiver which intercepts a signal proportional to the intensity of the object beam incident on the dispersing element; where light from the said optical illumination source is split in a main splitter between an object beam and a reference beam, where the object beam is sent towards the object via the adapter input where the path length from the main splitter along the object beam to the object and back to the main splitter and then along from one of the outputs of the main splitter to the 1st input of a 2nd splitter defines an object path and the path from the main splitter along the reference beam towards the 2nd input of the 2nd splitter defines a reference path an optical path difference adjusting block between the path lengths of the object path and the reference path; displacing means for laterally displacing the reference optical beam from the object beam in its path towards the optical dispersion element to shift the reference beam away from the entrance of the confocal receiver so that the confocal receiver receives a signal proportional to the intensity of the object beam only; means for processing at least one image captured by the camera sensor to generate depth resolved information from the object as the OCT channel; and means for producing an en-face image using the signal provided by the confocal receiver. - View Dependent Claims (18, 19)
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20. A method of high resolution imaging, comprising collecting cross section OCT images to sample the volume of the object;
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simultaneously collecting lines for an en-face image; and generating and providing a complete en-face image by the time all cross section OCT images have been completed. - View Dependent Claims (28, 29)
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21. A method of high resolution imaging of an object providing simultaneous measurement in two channels, a confocal channel and an optical coherence tomography (OCT) channel, the method comprising:
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providing an object and a reference beam respectively, the object beam passing from a light source to the object to be imaged and the object beam and the reference beam passing through an optical dispersion element directing both dispersed beams to a camera sensor where they interfere to generate depth resolved image data of the OCT channel; intercepting a signal proportional to the intensity of the object beam incident on the dispersion element in a confocal receiver; laterally displacing the reference optical beam from the object beam in their path towards the optical dispersion element to produce a shifted reference beam to shift the shifted reference beam away from the entrance of the confocal receiver, measuring the intensity of the object beam in the confocal detection of the object beam to provide the confocal channel; and producing an A-scan OCT by evaluating the FFT of the signal delivered by reading the camera.
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Specification