Patent ID: 8619156

Claim:
A method of controlling an image capturing system to capture underexposed image frames used to provide a final combined image comprising an interface comprising a microprocessor, an output device and an input device for receiving an external trigger to capture an image, and an image capturing device provided with a photosensitive area and an array of pixel cells, each pixel cell including a device for generating a signal indicative of the intensity of light falling on an associated part of the photosensitive area, which image capturing device is further provided with readout circuitry comprising a selection circuit and a readout circuit for generating an array of pixel values to capture an underexposed image frame at a set spatial resolution, such that each pixel value represents an integral of the signal or signals generated in at least one of the pixel cells in an associated one of a number of cluster areas over an exposure time interval, the number of cluster areas being determined by the set spatial resolution, the cluster areas together covering a region of the photosensitive area corresponding to a region in the image, which method comprises: receiving an external trigger to capture an image; and in response to the external trigger, directing the image capturing device to capture at least two underexposed image frames wherein the at least two underexposed image frames are captured by generating respective arrays of pixel values representing integrals over respective consecutive exposure time intervals, each exposure time interval being less than a desired exposure time of a final combined image, wherein the spatial resolutions of at least two of the captured image frames are set to different values and one of the spatial resolutions of one of the at least two captured image frames is lower than the spatial resolution of the at least one other captured image frame and wherein at least the length of the exposure time interval applicable to the image frame at the lower of the spatial resolution values is calculated in dependence of the spatial resolution value.