Abstract:
Ambient light is detected by a photodiode circuit by measuring the time taken for a digital output of the photodiode circuit to change state in response to exposure of a photodiode of the photodiode circuit to that ambient light. A nominal time for state change is calculated based on photodiode circuit characteristics. Furthermore, an effective time for the photodiode circuit digital output to change state is determined in a calibration mode where the photodiode has been disconnected and a reference current is applied to the circuit. An illumination value of the detected ambient light is then calculated as a function of: the measured time, the effective time and the nominal time.
Abstract:
An optical mouse includes an image sensor for providing image data via an analog-to-digital converter to a correlation circuit and a motion estimation circuit to provide output signals representative of motion of the mouse. The output signals may be disabled when the mouse is lifted away from the working surface. This may be achieved by high-pass filtering the signals, summing each frame in a summer to provide a single value, and comparing this to a threshold. If the filtered and summed value exceeds the threshold, this may indicate that the image contains in-focus objects, and that the mouse is on the working surface.
Abstract:
An optical navigation device is provided for detecting movement of a pointer, such as a finger, in three dimensions. A sensor obtains images of the pointer which have been illuminated by an illumination source, and an image scaling module determines the difference in size between images acquired by the image sensor to determine the difference in height of the pointer between images.
Abstract:
An optical mouse includes an image sensor for providing image data via an analog-to-digital converter to a correlation circuit and a motion estimation circuit to provide output signals representative of motion of the mouse. The output signals may be disabled when the mouse is lifted away from the working surface. This may be achieved by high-pass filtering the signals, summing each frame in a summer to provide a single value, and comparing this to a threshold. If the filtered and summed value exceeds the threshold, this may indicate that the image contains in-focus objects, and that the mouse is on the working surface.
Abstract:
An optical navigation device is provided for detecting movement of a pointer, such as a finger, in three dimensions. A sensor obtains images of the pointer which have been illuminated by an illumination source, and an image scaling module determines the difference in size between images acquired by the image sensor to determine the difference in height of the pointer between images.
Abstract:
Ambient light is detected by a photodiode circuit by measuring the time taken for a digital output of the photodiode circuit to change state in response to exposure of a photodiode of the photodiode circuit to that ambient light. A nominal time for state change is calculated based on photodiode circuit characteristics. Furthermore, an effective time for the photodiode circuit digital output to change state is determined in a calibration mode where the photodiode has been disconnected and a reference current is applied to the circuit. An illumination value of the detected ambient light is then calculated as a function of: the measured time, the effective time and the nominal time.
Abstract:
An image sequence sensor senses images. To associate a motion vector with an image of the sequence currently being processed, k candidate vectors are generated by adding, to a reference motion vector, respectively k search vectors. Then, a motion vector is selected from among the k candidate vectors as a function of a selection rule. Thereafter, the previous two steps are repeated m times, the reference motion vector being on the one hand, for a first iteration of the first step, an initial reference vector selected from among a set of vectors comprising at least one motion vector associated with a previous processed image and being on the other hand, for the m repetitions of the first step, the motion vector selected in the second step preceding the first step. Then, the vector obtained in the third step is associated with the image currently being processed.
Abstract:
A frequency-shift modulation device includes an oscillating circuit, a phase-locked loop and a digital frequency modulation circuit. The oscillating circuit is connected to the phase-locked loop in order to produce a fixed-frequency clock signal. This clock signal is used for timing the frequency modulation circuit. A standard model crystal oscillator can be used in the oscillating circuit, given that the RF frequency of a wireless transmission signal which is produced by the modulation device is determined digitally.
Abstract:
The invention provides a demodulation PLL wherein: the first position of a switch, which is controlled by a control circuit, respectively connects the outputs of a mixer and a LP filter to high gain and low gain inputs of an oscillator when frequency signals at the inputs of the mixer have not converged sufficiently, i.e. during the PLLs tuning mode; the second position of the switch respectively connects the outputs of the mixer and the LP filter to the low gain and high gain inputs of the oscillator when the frequency signals at the inputs of the mixer and the signal levels on the input and output of the filter have converged sufficiently, i.e. during the PLLs demodulation mode.
Abstract:
In relation to a current image from a sequence of images captured by an image sensor, in a first step, a temporary motion vector is determined as a function of reference data comprising a preceding image and a motion vector associated to the preceding image. Then, in a second step, if the temporary motion vector does not satisfy a reliability criterion, the first step is repeated in relation to a following image, on the basis of the same reference data. Otherwise, the temporary motion vector is associated with the current image.