Focusing mechanisms for compressive imaging device
First Claim
1. A method for focusing a compressive imaging (CI) device, the method comprising:
- (a) supplying a sequence of spatial patterns to a light modulation unit of the CI device, wherein the light modulation unit includes an array of light modulating elements;
(b) the light modulation unit modulating an incident light stream with the sequence of spatial patterns to produce a modulated light stream, wherein each of the spatial patterns is restricted to a subset of the array of light modulating elements;
(c) a light sensing device of the CI device receiving the modulated light stream and acquiring a sequence of samples representing an intensity of the modulated light stream as a function of time, wherein the sequence of samples includes at least one sample for each of the spatial patterns;
(d) constructing an image using the sequence of spatial patterns and the acquired samples;
(e) computing a focus indicator value based on the image, wherein the focus indicator value indicates an extent to which the incident light stream is in focus at the light modulation unit.
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Abstract
A compressive imaging (CI) device including a light modulator and a light sensor (e.g., a single-element sensor or a sensor array). The CI device may support the focusing of light on the light modulator and/or on the light sensor in a number of ways: (1) determining a focus indicator value by analyzing a 1D or 2D image in the incident light field; (2) measuring light spillover between modulator regions and light sensing elements—either at the level of voltage measurements or the level of reconstructed images; (3) measure noise in reconstructed sub-images; (4) measuring an amount high-frequency content in the incident light field; (5) incorporating a range finder to measure distance to the object being imaged; (6) incorporating an image sensor downstream from the modulator; and (7) splitting a portion of the incident light onto an image sensor, prior to the modulator.
45 Citations
44 Claims
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1. A method for focusing a compressive imaging (CI) device, the method comprising:
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(a) supplying a sequence of spatial patterns to a light modulation unit of the CI device, wherein the light modulation unit includes an array of light modulating elements; (b) the light modulation unit modulating an incident light stream with the sequence of spatial patterns to produce a modulated light stream, wherein each of the spatial patterns is restricted to a subset of the array of light modulating elements; (c) a light sensing device of the CI device receiving the modulated light stream and acquiring a sequence of samples representing an intensity of the modulated light stream as a function of time, wherein the sequence of samples includes at least one sample for each of the spatial patterns; (d) constructing an image using the sequence of spatial patterns and the acquired samples; (e) computing a focus indicator value based on the image, wherein the focus indicator value indicates an extent to which the incident light stream is in focus at the light modulation unit. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. A method for focusing a compressive imaging (CI) device, the method comprising:
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(a) supplying a sequence of spatial patterns to a light modulation unit of the CI device; (b) the light modulation unit modulating an incident light stream with the sequence of spatial patterns to produce a modulated light stream; (c) acquiring a sequence of the frames from an array of light sensing elements of the CI device, wherein each of the light sensing elements receives a respective spatial portion of the modulated light stream, wherein each of the frames corresponds to respective one of the spatial patterns, wherein each of the frames includes one sample from each of the light sensing elements; (d) determining a sequence of sum values, wherein each of the sum values is determined by adding the samples in a respective one of the frames of the acquired sequence; (e) constructing an image using the sequence of spatial patterns and the sequence of sum values; (f) computing a focus indicator value based on the image, wherein the focus indicator value indicates an extent to which the incident light stream is in focus at the light modulation unit.
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19. A method for focusing a compressive imaging (CI) device, the method comprising:
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(a) modulating an incident light stream with calibration patterns to obtain a modulated light stream, wherein said modulating is performed by a light modulation unit of the CI device, wherein the light modulation unit includes an array of light modulating elements; (b) an array of light sensing elements of the CI device receiving the modulated light stream, where the light sensing elements receive respective spatial portions of the modulated light stream and generate respective electrical signals, wherein each electrical signal represents intensity of the respective spatial portion as a function of time, wherein the light sensing elements correspond to respective non-overlapping regions within the array of light modulating elements, wherein each of the calibration patterns specifies that the light modulating elements inside a respective one of the regions are to be set to an off state and specifies that at least a subset of the light modulating elements outside the respective region are to be set to an on state; (c) for each of the calibration patterns, acquiring a respective group of samples from the array of light sensing elements, wherein each of the sample groups includes at least one sample of each of the electrical signals; (d) determining spillover values corresponding respectively to the calibration patterns, wherein each of the spillover values is determined based on the sample group corresponding to the respective calibration pattern, wherein each of the spillover values indicates an extent to which modulated light from outside the respective region of the array of light modulating elements reaches the light sensing element corresponding to the respective region; (e) computing a composite spillover value for the array of light sensing elements based on the spillover values. - View Dependent Claims (20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32)
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33. A method for focusing a compressive imaging (CI) device, the method comprising:
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(a) modulating an incident light stream with a calibration pattern to obtain a modulated light stream, wherein said modulating is performed by a light modulation unit of the CI device, wherein the light modulation unit includes an array of light modulating elements; (b) an array of light sensing elements of the CI device receiving the modulated light stream, where the light sensing elements receive respective spatial portions of the modulated light stream and generate respective electrical signals, wherein each electrical signal represents intensity of the respective spatial portion as a function of time, wherein the light sensing elements correspond to respective non-overlapping regions within the array of light modulating elements, wherein the calibration pattern specifies that the light modulating elements inside a first one of the regions are to be set to an off state and specifies that at least a subset of the light modulating elements outside the first region are to be set to an on state, wherein the first region corresponds to a first of the light sensing elements; (c) acquiring samples of the electrical signal generated by the first light sensing element in response to said modulating the incident light stream with the calibration pattern, wherein each of the samples indicates an extent to which modulated light from outside the first region of the array of light modulating elements reaches the first light sensing element.
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34. A method for determining focus-related information for a compressive imaging (CI) device, the method comprising:
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(a) modulating an incident light stream with a sequence of spatial patterns to obtain a modulated light stream, wherein said modulating is performed by a light modulation unit of the CI device, wherein the light modulation unit includes an array of light modulating elements; (b) an array of light sensing elements of the CI device receiving the modulated light stream, wherein the light sensing elements receive respective spatial portions of the modulated light stream and generate respective electrical signals, wherein each of the electrical signals represents intensity of the respective spatial portion as a function of time, wherein the light sensing elements correspond to respective non-overlapping regions of the array of light modulating elements; (c) acquiring measurements from the array of light sensing elements, wherein the measurements include sample sets that correspond respectively to the light sensing elements, wherein each sample set includes samples of the electrical signal generated by the respective light sensing element, with the samples including at least one sample for each of the spatial patterns; (d) computing a focus indicator value based on two or more noise values for two or more respective ones of the light sensing devices, wherein the focus indicator value indicates an extent to which the modulated light stream is in focus at the sensor array, wherein each of the two or more noise values is computed by; constructing a respective sub-image based on the sample set of the respective light sensing element and also on a restriction of the spatial patterns to the region of the array of light modulating elements corresponding to the respective light sensing element; and computing an amount of noise present in the respective sub-image. - View Dependent Claims (35, 36, 37, 38)
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39. A method for determining focus-related information for a compressive imaging (CI) device, the method comprising:
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(a) modulating an incident light stream with a sequence of spatial patterns to obtain a modulated light stream, wherein said modulating is performed by a light modulation unit of the CI device, wherein the light modulation unit includes an array of light modulating elements; (b) an array of light sensing elements of the CI device receiving the modulated light stream, wherein the light sensing elements receive respective spatial portions of the modulated light stream and generate respective electrical signals, wherein each of the electrical signals represents intensity of the respective spatial portion as a function of time, wherein the light sensing elements correspond to respective non-overlapping regions of the array of light modulating elements; (c) acquiring a set of samples from a first of the light sensing elements, wherein the sample set includes samples of the electrical signal generated by the first light sensing element, with the samples including at least one sample for each of the spatial patterns; (d) computing a focus indicator value for the first light sensing device, wherein the focus indicator value indicates an extent to which the modulated light stream is in focus at the sensor array, wherein the focus indicator value is computed by; constructing a sub-image based on the sample set and on a restriction of the spatial patterns to a the region of the array of light modulating elements corresponding to the first light sensing element; and computing an amount of noise present in the sub-image.
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40. A method for determining focus-related information for a compressive imaging (CI) device, the method comprising:
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(a) modulating an incident light stream with a sequence of spatial patterns to obtain a modulated light stream, wherein said modulating is performed by a light modulation unit of the CI device, wherein the light modulation unit includes an array of light modulating elements; (b) an array of light sensing elements of the CI device receiving the modulated light stream, wherein the light sensing elements receive respective spatial portions of the modulated light stream and generate respective electrical signals, wherein each of the electrical signals represents intensity of the respective spatial portion as a function of time, wherein the light sensing elements correspond to respective non-overlapping regions on the array of light modulating elements; (c) acquiring measurements from the array of light sensing elements, wherein the measurements include sample sets that correspond respectively to the light sensing elements, wherein each sample set includes samples of the electrical signal generated by the respective light sensing element, with the samples including at least one sample for each of the spatial patterns; (d) computing a focus indicator value based on two or more spillover values for two or more respective ones of the light sensing devices, wherein the focus indicator value indicates an extent to which the modulated light stream is in focus at the sensor array, wherein each of the two or more spillover values is computed by; constructing a respective image based on the sample set of the respective light sensing element and also on the spatial patterns; summing pixels in the image outside the region corresponding to the respective light sensing element.
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41. A method for determining focus-related information for a compressive imaging (CI) device, the method comprising:
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(a) modulating an incident light stream with a sequence of spatial patterns to obtain a modulated light stream, wherein said modulating is performed by a light modulation unit of the CI device, wherein the light modulation unit includes an array of light modulating elements; (b) an array of light sensing elements of the CI device receiving the modulated light stream, wherein the light sensing elements receive respective spatial portions of the modulated light stream and generate respective electrical signals, wherein each of the electrical signals represents intensity of the respective spatial portion as a function of time, wherein the light sensing elements correspond to respective non-overlapping regions on the array of light modulating elements; (c) acquiring measurements from the array of light sensing elements, wherein the measurements include sample sets that correspond respectively to the light sensing elements, wherein each sample set includes samples of the electrical signal generated by the respective light sensing element, with the samples including at least one sample for each of the spatial patterns; (d) computing a spillover value for a first of the light sensing devices, wherein the spillover value indicates an extent to which the modulated light stream is in focus at the sensor array, wherein the spillover value is computed by; constructing an image based on the sample set corresponding to the first light sensing element and also on the spatial patterns; summing pixels in the image outside the region corresponding to the first light sensing element.
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42. A method for focusing a compressive imaging (CI) device, the method comprising:
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(a) supplying a sequence of spatial patterns to a light modulation unit of the CI device; (b) the light modulation unit modulating an incident light stream with the sequence of spatial patterns to produce a modulated light stream; (c) a light sensing device of the CI device receiving the modulated light stream and acquiring a sequence of samples representing an intensity of the modulated light stream as a function of time, wherein the sequence of samples includes at least one sample for each of the spatial patterns; (d) constructing an image using the sequence of spatial patterns and the acquired samples; (e) computing a focus indicator value based on the image, wherein the focus indicator value indicates an extent to which the incident light stream is in focus at the light modulation unit; and (f) changing an angle of orientation of the light modulation unit based on data including the focus indicator value.
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43. A method for focusing a compressive imaging (CI) device, the method comprising:
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(a) supplying a sequence of spatial patterns to a light modulation unit of the CI device; (b) the light modulation unit modulating an incident light stream with the sequence of spatial patterns to produce a modulated light stream; (c) a light sensing device of the CI device receiving the modulated light stream and acquiring a sequence of samples representing an intensity of the modulated light stream as a function of time, wherein the sequence of samples includes at least one sample for each of the spatial patterns, wherein the light sensing device includes a plurality of light sensing elements, wherein each of the light sensing elements generates a respective electrical signal representing intensity of a respective spatial portion of the modulated light stream, wherein said acquiring the sequence of samples comprises adding the electrical signals to obtain a sum signal and sampling the sum signal; (d) constructing an image using the sequence of spatial patterns and the acquired samples; (e) computing a focus indicator value based on the image, wherein the focus indicator value indicates an extent to which the incident light stream is in focus at the light modulation unit.
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44. A method for focusing a compressive imaging (CI) device, the method comprising:
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(a) supplying a sequence of spatial patterns to a light modulation unit of the CI device; (b) the light modulation unit modulating an incident light stream with the sequence of spatial patterns to produce a modulated light stream; (c) a light sensing device of the CI device receiving the modulated light stream and acquiring a sequence of samples representing an intensity of the modulated light stream as a function of time, wherein the sequence of samples includes at least one sample for each of the spatial patterns, wherein the light sensing device includes a plurality of light sensing elements, wherein each of the light sensing elements generates a respective electrical signal representing intensity of a respective spatial portion of the modulated light stream, wherein said acquiring the sequence of samples comprises sampling each of the electrical signals and adding the sampled versions of the electrical signals in the digital domain; (d) constructing an image using the sequence of spatial patterns and the acquired samples; (e) computing a focus indicator value based on the image, wherein the focus indicator value indicates an extent to which the incident light stream is in focus at the light modulation unit.
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Specification