Abstract: A method includes defining a background model of the video sequence by applying a first algorithm, the background model defining whether that spatial area belongs to a background or a foreground in the video sequence, wherein a detected significant change in image data in a spatial area in an image frame relative image data in said spatial area in a preceding image frame is indicative of said spatial area belonging to the foreground; indicating that an idle area of the defined foreground areas is to be transitioned from foreground to background; and determining whether the idle area is to be transitioned by applying a second algorithm to image data of an image frame of the video sequence, the image data at least partly corresponding to the idle area; wherein if the idle area is not to be transitioned, maintaining the idle area as a foreground area in the background model.

Abstract: A system, apparatus, computer program product, and method perform controlled video recording of video captured by a camera. The method includes checking by recorder circuitry of receipt of a ping signal sent from a server to the recorder, the ping signal being expected to be received by the recorder circuitry within a predetermined time interval after an earlier ping signal was received (or when an initial ping signal was expected to be received), in response to a determination by the recorder circuitry of not receiving the ping signal, entering an autonomous recording mode, the autonomous recording mode including recording video provided from at least one camera, and continuing operation of the autonomous recording mode until at least one of receiving another ping signal by the recorder circuitry, or receiving a control signal from the server that directs the recorder to stop recording the video provided from the at least one camera.

Abstract: A method for identifying stationary regions in frames of a video sequence comprises receiving an encoded version of the video sequence, wherein the encoded version of the video sequence includes an intra-coded frame followed by a plurality of inter-coded frames; reading coding-mode information in the inter-coded frames of the encoded version of the video sequence, wherein the coding-mode information is indicative of blocks of pixels in the inter-coded frames being skip-coded; finding, using the read coding-mode information, one or more blocks of pixels that each was skip-coded in a respective plurality of consecutive frames in the encoded version of the video sequence; and designating each found block of pixels as a stationary region in the respective plurality of consecutive frames.

Abstract: An image processor and a method therein to provide a target image for evaluation with an object detector. The method comprises: obtaining a source image captured by a camera and depicting an object, and applying an inverse pixel transform to each target pixel of a target image to determine one or more source pixels located at a position in the source image corresponding to a position of each target pixel in the target image. The method further comprises assigning, to each target pixel, a target pixel value determined based on one or more source pixel values of the determined one or more source pixels located at the corresponding position, thereby is a size c in the target image of the depicted object of a specific object type normalized in at least one size dimension. Thereafter, the target image is fed to an object detector for evaluation.

Abstract: A method for mapping a static scene using a stationary radar unit operative to transmit radar signals towards a scene, the stationary radar unit comprises a set of receiver antennas configured to detect radar signals from arbitrary directions, and the stationary radar unit is configured to measure target velocity in discrete velocity bins, the method comprising: continuously collecting radar signals over time to detect a static scene using the set of receiver antennas; constructing an occupancy map of the static scene using confirmed detections determined from the collected radar signals, where confirmed detections are detections with radar signal strength exceeding a detection threshold and with velocity falling in a zero velocity bin and detections with radar signal strength exceeding the detection threshold and with a non-zero velocity sufficiently low to cause spill over information in the same bin as detections falling in the zero velocity bin.

Abstract: A method for classifying tracks in radar detections of a scene acquired by a stationary radar unit, comprises: acquiring radar detections of the scene using the static radar unit; feeding at least a portion of the radar detections into a tracker module for producing track-specific feature data indicating a specific track in the scene, feeding at least a portion of the radar detections into a scene model comprising information about scene-specific features aggregated over time, and information indicating areas in the scene with expected ghost target detections and areas with expected real target detections, wherein at least a subset of the scene-specific features is determined from the radar detections; classifying the specific track as belonging to a real target or to a ghost target by relating the specific track to a position in the scene model.

Abstract: A device, and method of signing a video segment comprising one or more groups of pictures, GOPs, wherein each GOP comprises a header and one or more frames, are disclosed. For each of the one or more GOPs a GOP hash is produced and the GOP hash is digitally signed by means of a digital signature to produce a signed GOP hash. For each GOP except a last GOP of the one or more GOPs the respective signed GOP hash is saved in the header of a subsequent GOP. An additional GOP is added to the video segment after the last GOP of the one or more GOPs, wherein the additional GOP comprising a header and one or more frames. The signed GOP hash of the last GOP of the one or more GOPs is saved in the header of the additional GOP.

Abstract: A device and method merge a first candidate area relating to a candidate feature in a first image and a second candidate area relating to a candidate feature in a second image. The first and second images have an overlapping region, and at least a portion of the first and second candidate areas are located in the overlapping region. An image overlap size is determined indicating a size of the overlapping region of the first and second images, and a candidate area overlap ratio is determined indicating a ratio of overlap between the first and second candidate areas. A merging threshold is then determined based on the image overlap size, and, on condition that the candidate area overlap ratio is larger than the merging threshold, the first candidate area and the second candidate area are merged, thereby forming a merged candidate area.

Abstract: There is provided a method for capturing a sequence of image frames in a thermal camera having a microbolometer detector comprising: capturing a first sequence and a second sequence of image frames with a shutter of the thermal camera being in a closed state and an open state, respectively. While capturing each of the first and the second sequence, an integration time of the microbolometer detector is switched between a plurality of integration times according to one or more repetitions of a temporal pattern of integration times. The method further comprises correcting image frames in the second sequence that are captured when the integration time is switched to a particular position within the temporal pattern of integration times using image frames in the first sequence that are captured when the integration time is switched to the same particular position within the temporal pattern of integration times.

Abstract: A method for determining whether or not a transparent protective cover of a video camera comprising a lens-based optical imaging system is partly covered by a foreign object is disclosed. The method comprises: obtaining (402) a first captured image frame captured by the video camera with a first depth of field; obtaining (404) a second captured image frame captured by the video camera with a second depth of field which differs from the first depth of field; and determining (406) whether or not the protective cover is partly covered by the foreign object by analysing whether or not the first and second captured image frames are affected by presence of the foreign object on the protective cover such that the difference between the first depth of field and the second depth of field results in a difference in a luminance pattern of corresponding pixels of a first image frame and a second image frame.

Abstract: A camera for introducing light pulses in an image stream, comprising an image sensor arranged to capture an image stream, the image sensor comprising a plurality of pixels arranged to capture light of a first wavelength range. The at least one of the plurality of pixels is covered by a first material which is arranged to transform light of a second wavelength range to light of the first wavelength range. Further the camera comprises a first light source arranged to emit light pulses of light of the second wavelength range onto the first material, thereby causing the image sensor to register light pulses in the at least one pixel covered by the first material.

Abstract: An image processing device, a camera and a method of encoding a sequence of video images into a single video stream with dynamic bitrate are provided. The sequence of video images is encoded into frames of a base layer of the single video stream using a base layer resolution and a base layer compression level. Video images of the sequence of video images corresponding to respective times before detecting an event trigger are encoded into a first set of frames of an extended layer of the single video stream. The event trigger is detected and upon detecting the event trigger, video images of the sequence of video images corresponding to respective times after detecting the event trigger are encoded into a second set of frames of the extended layer using a higher resolution than the base layer resolution or a lower compression level than the base layer compression level.

Abstract: An exposure time controller for controlling an exposure time (ET) variable of a video camera, which is associated with an auto-exposure algorithm configured to reduce an exposure mismatch (?E) by incrementing and decrementing the ET variable, which comprises: a memory for recording ET values applied while the video camera is imaging a scene and the algorithm is active; and processing circuitry configured to: determine that the exposure mismatch exceeds a threshold while the video camera is imaging the scene; estimate a distribution of the recorded ET values; based on the estimated distribution, identify multiple relatively most frequent ET values; and, in reaction to determining that the exposure mismatch exceeds the threshold, assign one of the identified ET values to the ET variable.

Abstract: A threaded joint arrangement with visual and tactile indication of correct tightening force, includes a threaded fastener having a fastener shaft and a fastener head, a biasing member, a first object provided with a cavity in a reference surface with a bottom surface provided with a through hole, and a second object with a threaded hole. The through hole is aligned with the threaded hole and the fastener shaft extends through the through hole and is in threaded engagement with the threaded hole. The biasing member is arranged in the cavity between the fastener head and the bottom surface and is compressed between the fastener head and the bottom surface in response to rotation of the threaded fastener. An alignment surface is movable by rotation of the threaded fastener between a first position outside the cavity, a second position flush with the reference surface and a third position inside cavity.

Abstract: There is provided a computer implemented method for displaying a video stream of a scene (100) captured by a video capture device on a display of a client device.

Abstract: A method for determining images plausible to have a false negative object detection comprises providing a group of historic trajectories, wherein each historic trajectory comprises a reference track that represents one or more historic tracks and comprises an object class of historic object detections that belong to the one or more historic tracks; performing tracking; performing object detection; for a determined track that does not match any determined object detection, comparing the determined track with reference tracks of historic trajectories for identifying a matching reference track; upon identifying a matching reference track, defining images of the determined track as being plausible to have a false negative object detection for the object class of the historic trajectory comprising the matching reference track; and upon not identifying a matching reference track, defining the determined track as a false positive track.

Abstract: A method for enhancing the performance of a video camera capable of switching between night-mode and day-mode operation comprises: acquiring a first sequence of images with the video camera with an IR-transmission filter of known transmission characteristics in front of an image sensor of the video camera, the IR transmission filter having a transmission in the IR-region of above 30%, and acquiring a second sequence of images with the video camera without the IR-transmission filter. The method then uses the first and second image sequences to measure the contribution from visual light, or a contribution of IR radiation to images in the first or second stream of images. The measurements utilize an assessment of the calculated contribution to improve the performance of the video camera by switching the video camera from night-mode to day-mode, or add color information to images acquired with IR-radiation to the image sensor.

Abstract: Methods and apparatus, including computer program products, for detecting malfunction in a thermal camera. A first average response value is determined for a first shutter image captured by an image sensor in the thermal camera. A second average response value is determined of a second shutter image captured by the image sensor in the thermal camera. The first average response value and the second average response value are compared. In response to determining that the first average response value and the second average response value differ by more than a predetermined value, an indication of a malfunction of the thermal camera is provided.