A method for multi-target detection and an apparatus for multi-target detection are capable of detecting at least two targets in real time or near real time. The real-time detection or near real time detection can be achieved by at least one of a Recipe Group Approach, an End Member Grouping Approach, and a Pixelated Grouping Based Approach.

A system includes a lighting module, a processing module, and photovoltaic units. Each of the photovoltaic units receives light reflected off a body portion which is illuminated by light from the lighting module, and converts light energy of the reflected light into electricity. The processing module stores modes each of which specifies a code set. When one of the modes is selected, the processing module activates the lighting module to emit light based on the code set specified by the mode thus selected. The processing module converts electrical quantities measured individually for the photovoltaic units into respective code parameters, and composes an identification code using the code parameters.

In an embodiment, a method (100) is described. The method comprises obtaining (102) a three-dimensional representation of a body surface. The method further comprises obtaining illumination information for the three-dimensional representation that is indicative of an orientation of the body surface relative to a reference axis. The method further comprises determining illumination compensation information (104). The illumination compensation information is used (106) to compensate for an illumination variation apparent from the illumination information in an image of the body surface.

A device for determining a face of a dice resting on a surface allowing an optical signal to pass, the dice being composed of a plurality of faces each including a visual marking uniquely identifying the face, and the device including: illumination means for illuminating a face of a dice through the surface, the illumination means being placed under the surface and oriented in the direction of the surface, the illumination means including a plurality of optical signal sources disposed at various positions under the surface; means for acquiring at least one image of the optical signals reflected by the face of the dice resting on the surface, the acquisition means being placed under the surface and being facing the surface; and an analysis unit including means for processing the image to determine the face of the dice resting on the surface allowing the optical signal to pass.

A device for determining a face of a dice resting on a surface allowing an optical signal to pass, the dice being composed of a plurality of faces each including a visual marking uniquely identifying the face, and the device including: illumination means for illuminating a face of a dice through the surface, the illumination means being placed under the surface and oriented in the direction of the surface, the illumination means including a plurality of optical signal sources disposed at various positions under the surface; means for acquiring at least one image of the optical signals reflected by the face of the dice resting on the surface, the acquisition means being placed under the surface and being facing the surface; and an analysis unit including means for processing the image to determine the face of the dice resting on the surface allowing the optical signal to pass.

Image processing includes obtaining image I[0,0] of a picture captured by an image capture means, in a state where light is irradiated to the picture from a light source at a reference position relative to a normal line of the picture, obtaining image I[α1,0] of the picture captured by an image capture means, in a state where the light is irradiated to the picture from the light source at a position inclined from the reference position at an angle α1 in the first direction, obtaining image I[0, β1] of the picture captured by an image capture means, in a state where the light is irradiated to the picture from the light source at a position inclined by an angle β1 from the reference position in a second direction different from the first direction, creating a three-dimensional map of the picture, using a set of images I[0, β1] and I[0, β2], merging at least a part of each of image I[α1,0], image I[0,β1], and image I[0,β2] with respect to image I[0,0], and recording as two-dimensional image data the image subjected to the emphasizing process.

Image processing includes obtaining image I[0,0] of a picture captured by an image capture means, in a state where light is irradiated to the picture from a light source at a reference position relative to a normal line of the picture, obtaining image I[α1,0] of the picture captured by an image capture means, in a state where the light is irradiated to the picture from the light source at a position inclined from the reference position at an angle α1 in the first direction, obtaining image I[0, β1] of the picture captured by an image capture means, in a state where the light is irradiated to the picture from the light source at a position inclined by an angle β1 from the reference position in a second direction different from the first direction, creating a three-dimensional map of the picture, using a set of images I[0, β1] and I[0, β2], merging at least a part of each of image I[α1,0], image I[0,β1], and image I[0,β2] with respect to image I[0,0], and recording as two-dimensional image data the image subjected to the emphasizing process.

A device includes an offset subtraction unit; an image sensor which receives, for each of a plurality of bright frames, a respective image signal obtained during a respective exposure time of the image sensor, and transmits the same to the offset subtraction unit, and receives, for a dark frame, a respective image signal obtained during a respective exposure time of the image sensor, and transmits the same to the offset subtraction unit; and a control unit which ensures that the image sensor alternately transmits a number of bright frames and one dark frame to the offset subtraction unit. An amount of light by which the respective image signal for each of the bright frames is generated is larger than an amount of light by which the respective image signal for the dark frame is generated; and the offset subtraction unit obtains an offset and subtracts the offset from a signal.

A device includes an offset subtraction unit; an image sensor which receives, for each of a plurality of bright frames, a respective image signal obtained during a respective exposure time of the image sensor, and transmits the same to the offset subtraction unit, and receives, for a dark frame, a respective image signal obtained during a respective exposure time of the image sensor, and transmits the same to the offset subtraction unit; and a control unit which ensures that the image sensor alternately transmits a number of bright frames and one dark frame to the offset subtraction unit. An amount of light by which the respective image signal for each of the bright frames is generated is larger than an amount of light by which the respective image signal for the dark frame is generated; and the offset subtraction unit obtains an offset and subtracts the offset from a signal.

An apparatus (1, 5, 6) is described which includes two or more colour displays (2) arranged to provide piece-wise continuous illumination of a volume. The apparatus (1, 5, 6) also includes one or more cameras (3). Each camera (3) is arranged to image the volume. The apparatus (1, 5, 6) is configured to control the two or more colour displays (2) and the one or more cameras (3) to illuminate the volume with each of two or more illumination conditions. The apparatus (1, 5, 6) is also configured to obtain two or more sets of images. Each set of images is obtained during illumination of the volume with one or more corresponding illumination conditions. The two or more sets of images include sufficient information for calculation of a reflectance map and a photometric normal map of an object or subject (4) positioned within the volume. When viewed from the volume, the apparatus (1, 5, 6) only provides direct illumination of the volume from angles within a zone of a hemisphere. The zone is less than a hemisphere and corresponds to a first range (Δα) of latitudinal angles and a second range (Δβ) of longitudinal angles. Each of the first (Δα) and second ranges (Δβ) is no more than 17π/18.