Abstract: A method includes controlling a light source to output a first intensity of light while an image-capturing device captures a scene in a first upcoming image frame with a first exposure value setting, controlling the light source to switch from the first to a second intensity of light so the light source outputs the second intensity of light while capturing the scene with a second upcoming image frame with a second exposure value setting, wherein the second intensity of light is higher than the first intensity of light when the second exposure value setting is higher than the first exposure value setting, and the second intensity of light is lower than the first when the second exposure value setting is lower than the first exposure value setting, and stitching the first upcoming image frame with the second upcoming image frame into a high-dynamic range image frame.

Abstract: A method of performing better controlled switching between day mode and night mode imaging in a camera, where those illuminants contributing to the ambient light in day mode are considered when determining the visible light during night mode. Characteristic values of those illuminants are mixed with several levels of IR light to simulate the presence of an IR illuminator, and these characteristic values are compared to corresponding values derived from the color components of the ambient light in night mode in order to determine the IR proportion, and from that the amount of visible light.

Abstract: A method for assessing an ambient light level during video acquisition with a video camera is provided. The video camera is operably connected with an IR illuminator, and having a day mode in which an IR-cut filter is arranged in front of an image sensor and a night mode in which the IR-cut filter is not arranged in front of the image sensor. The method comprises: acquiring a stream of images with the video camera in night mode, with the IR illuminator having a first illumination output level, and then reducing an output level of the IR illuminator to a predetermined illumination output level during acquisition of a sequence of a predetermined number of consecutive image frames within the image stream, and then assessing a measure representative of an ambient light level from an evaluation of the sequence of image frames.

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: A method includes controlling a light source to output a first intensity of light while an image-capturing device captures a scene in a first upcoming image frame with a first exposure value setting, controlling the light source to switch from the first to a second intensity of light so the light source outputs the second intensity of light while capturing the scene with a second upcoming image frame with a second exposure value setting, wherein the second intensity of light is higher than the first intensity of light when the second exposure value setting is higher than the first exposure value setting, and the second intensity of light is lower than the first when the second exposure value setting is lower than the first exposure value setting, and stitching the first upcoming image frame with the second upcoming image frame into a high-dynamic range image frame.

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: A method for assessing an ambient light level during video acquisition with a video camera is provided. The video camera is operably connected with an IR illuminator, and having a day mode in which an IR-cut filter is arranged in front of an image sensor and a night mode in which the IR-cut filter is not arranged in front of the image sensor. The method comprises: acquiring a stream of images with the video camera in night mode, with the IR illuminator having a first illumination output level, and then reducing an output level of the IR illuminator to a predetermined illumination output level during acquisition of a sequence of a predetermined number of consecutive image frames within the image stream, and then assessing a measure representative of an ambient light level from an evaluation of the sequence of image frames.

Abstract: A video camera system comprises an imaging system having a camera lens and an image sensor, and a retractable IR-cut filter, and a control unit for controlling the imaging system. The video camera system has a day-mode in which the IR-cut filter is arranged in front of the image sensor, and a night-mode in which the IR-cut filter is retracted from its position in front of the image sensor. Furthermore, the video camera has a field of view defined by properties of its imaging system, and it comprises a separate light-sensor for measuring an ambient light level so as to support a decision regarding when to actuate a transfer from night-mode to day-mode, or vice versa. The camera system is characterized in that the separate light sensor has imaging optics and is enabled for a variable field of view, which is aligned with a field of view of the video camera system, and in that a current field of view of the video camera system is used when selecting an active field of view of the separate light sensor.

Abstract: A video camera system comprises an imaging system having a camera lens and an image sensor, and a retractable IR-cut filter, and a control unit for controlling the imaging system. The video camera system has a day-mode in which the IR-cut filter is arranged in front of the image sensor, and a night-mode in which the IR-cut filter is retracted from its position in front of the image sensor. Furthermore, the video camera has a field of view defined by properties of its imaging system, and it comprises a separate light-sensor for measuring an ambient light level so as to support a decision regarding when to actuate a transfer from night-mode to day-mode, or vice versa. The camera system is characterized in that the separate light sensor has imaging optics and is enabled for a variable field of view, which is aligned with a field of view of the video camera system, and in that a current field of view of the video camera system is used when selecting an active field of view of the separate light sensor.