Dynamic range

About: Dynamic range is a research topic. Over the lifetime, 7576 publications have been published within this topic receiving 101739 citations. The topic is also known as: DNR & DR.

Force spectroscopy with a large dynamic range using small cantilevers and an array detector

Abstract: The important characteristics of a detector for force spectroscopy measurements are sensitivity, linearity and dynamic range. The commonly used two-segment detector that measures the position of a light beam reflected from the force-sensing cantilever in an atomic force microscope becomes nonlinear when the beam shifts significantly onto one of the segments. For a detection setup optimized for high sensitivity, such as needed for the use with small cantilevers, it is shown both experimentally and theoretically that the dynamic range extends to an upper detection limit of only about 115 nm in cantilever deflection if <10% nonlinearity is required. A detector is presented that circumvents that limitation. This detector is based on a linear arrangement of multiple photodiode segments that are read out individually. With such an array detector, the irradiance distribution of the reflected beam is measured. The reflected beam not only shifts in position but also deforms when the cantilever deflects because the bent cantilever acts as a curved mirror. The mean of the distribution, however, is a linear function of cantilever deflection in both theory and experiment. An array detector is consequently well suited for force measurements for which both high sensitivity and a large dynamic range are required.

Image signal processing apparatus having function for compressing dynamic range and correcting color saturation

Abstract: An input section receives an image signal including signals related to colors to output at least a luminance signal component of the image signal. A compressing section compresses the dynamic range of the luminance signal component from the input section. A setting section obtains a compression coefficient from a relationship between the luminance signal component whose dynamic range is compressed by the compressing section and the luminance signal component from the input section. An operating section executes an operation for compressing dynamic ranges of the signals related to colors included in the image signal in accordance with the compression coefficient obtained by the setting section. A correcting section substantially corrects the color saturation of the signals related to a color included in the image signal while preserving the luminance of the image signal such that the color saturation is more intensively suppressed as the luminance becomes lower.

Multimode fiber-optic hydrophone based on a schlieren technique

Abstract: A multimode fiber-optic hydrophone is described which is based upon a schlieren acoustooptic intensity modulation mechanism. Computer modeling of critical device parameters was experimentally verified and used to indicate ultimate attainable device performance. The device was shown to be able to detect the Knudsen noise level for frequencies up to 1 kHz, to have a dynamic range of 125 dB, to have an omnidirectional receiving response, and to be able to detect displacements as small as 3.4 × 10−3 A. The device is not susceptible to phase noise, is relatively insensitive to static pressure head variations and is electrically passive.

An Activity-Triggered 95.3 dB DR $-$ 75.6 dB THD CMOS Imaging Sensor With Digital Calibration

Abstract: Imaging sensors are being used as data acquisition systems in new biomedical applications. These applications require wide dynamic range (WDR), high linearity and high signal-to-noise ratio (SNR), which cannot be met simultaneously by existing CMOS imaging sensors. This paper introduces a new activity-triggered WDR CMOS imaging sensor with very low distortion. The new WDR pixel includes self-resetting circuits to partially quantize the photocurrent in the pixel. The pixel residual analog voltage is further quantized by a low-resolution column-wise ADC. The ADC code and the partially quantized pixel codes are processed by column-wise digital circuits to form WDR images. Calibration circuits are included in the pixel to improve the pixel linearity by a digital calibration method, which requires low calibration overhead. Current-mode difference circuits are included in the pixel to detect activities within the scene so that the imaging sensor captures high quality images only for scenes with intense activity. A proof-of-concept 32 times 32 imaging sensor is fabricated in a 0.35 mum CMOS process. The fill factor of the new pixel is 27%. Silicon measurements show that the new imaging sensor can achieve 95.3 dB dynamic range with low distortion of -75.6 dB after calibration. The maximum SNR of the sensor is 74.5 dB. The imaging sensor runs at frame rate up to 15 Hz.

Applications of digital micro-mirror devices to digital optical microscope dynamic range enhancement

Abstract: In this paper, we present a method of using digital micro-mirror devices to dynamic range enhancement of a digital optical microscope images. Our adaptive feedback illumination control generates a high dynamic range image through an algorithm that combines the DMD-to-camera pixel geometrical mapping and a feedback operation. The feedback process automatically generates an illumination pattern in an iterative fashion that spatially modulates the DMD array elements on pixel-by-pixel level. Via experiment, we demonstrate a system that uses precise DMD control of the projector to enhance the dynamic range ideally by a factor of 573. Results are presented showing approximately 5 times the camera dynamic range, enabling visualization over a wide range of specimen characteristics.