System and method for detecting target substances
A method includes capturing a signal of a detection substrate exposed to a sample containing a target substance; determining that the detection substrate is in a testable state; and generating an assessment of the presence of the target substance in the sample.
1. A system for optical detection of target substances, comprising:
a detection window comprising a broad face and configured to provide optical access to a surface of a detection substrate;
a set of light emitters configured to transmit light through the broad face of the detection window and onto the surface of the detection substrate according to an illumination pattern, the illumination pattern comprising a non-uniform distribution of radiant flux received at the surface of the detection substrate; wherein the non-uniform distribution comprises a radiant flux intensity that is greater at an edge region of the detection substrate than a center region of the detection substrate;
an imager, comprising a detector and an imaging aperture, wherein the imaging aperture is configured to produce an image of the detection substrate at the detector based on light emitted by the set of light emitters and scattered by the detection substrate; and
a housing statically mounting the illuminator, imager, and detection window, the housing defining an asymmetric test container receptacle configured to removably receive a test container comprising the detection substrate, the asymmetric test container keyed to align the test container in a testing configuration, wherein the detection substrate is arranged proximal to and aligned with the detection window in the testing configuration.
2. The system of claim 1 , wherein the imaging aperture comprises a set of apertures, each aperture configured to produce an image of a region of the detection substrate at a corresponding region of the detector.
3. The system of claim 2 , wherein there is a one to one correspondence between each of a set of regions of the detection substrate and each of a set of corresponding regions of the detector.
4. The system of claim 1 , wherein the imager is positioned distal to a plane extending perpendicularly from a midline of the broad face of the detection window, and the detector is positioned at an oblique angle relative to the broad face of the detection window, such that light specularly reflected by the detection window does not reach the detector.
5. The system of claim 1 , further comprising a baffle coupled to the set of light emitters, wherein the baffle obstructs light specularly reflected by the detection window and the detection substrate such that specularly reflected light is substantially prevented from reaching the detector.
6. The system of claim 1 , wherein at least a subset of the set of light emitters is partially obstructed by a portion of the imager such that predominantly an edge region of the detection window is illuminated.
7. The system of claim 1 , wherein the set of light emitters comprises a first light emitter, positioned at a first end of the imager, and a second light emitter, positioned at a second end of the imager; wherein the first and second light emitters are positioned to direct light toward the detection window at an acute angle relative to the broad face of the detection window.
8. The system of claim 1 , wherein the imaging aperture comprises a slit having a width, wherein the width is determined according to a desired mapping between regions of the detection substrate and regions of the detector at which the image of the detection substrate is formed.
9. The system of claim 8 , wherein the desired mapping comprises a one to one correspondence between regions of the detection substrate and regions of the detector.
10. The system of claim 1 , wherein the non-uniform distribution is determined by the corresponding power level and corresponding optical axis of each of the set of light emitters.
11. The system of claim 10 , wherein the non-uniform distribution is determined by a relative spacing between each of the set of light emitters.