EMVA 1288 Camera characterisation and the influences of radiometric camera characteristics on geometric measurements

Rosenberger, Maik; Zhang, Chen; Votyakov, Pavel; Preißler, Marc; Notni, Gunther

doi:10.21014/acta_imeko.v5i4.356

Cited by 9 publications

(7 citation statements)

References 8 publications

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“…In order to know the impact of distortion in the image coordinate measurement accuracy, a Monte Carlo method was used [21], considering the results shown in Table 1 and the mathematical models given by expressions (16)(17)(18)(19). The computational simulation algorithm was developed in Matlab ® , using the Mersenne-Twister pseudo-random number generator [25] and validated computational routines.…”

Section: Resultsmentioning

confidence: 99%

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Optical metrology applied in CCTV inspection in drain and sewer systems

2020

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<p class="Abstract">This paper addresses the metrological quality of dimensional measurements based on images obtained from CCTV inspections in drain and sewer systems. In this type of indirect visual inspection, a significant number of absolute and relative dimensional quantities can be quantified, contributing to the characterization of the observations and, consequently, to the analysis of performance of drain and sewer systems outside buildings. Unfavorable environmental factors and conditions within the drain or sewer components affect estimation of the quantities of interest and the quality of the recorded images (lighting, lack of reference points, geometric irregularities and subjective assessments, among others). Quantification improvement of the dimensional quantities is a key objective to achieve a better assessment of components condition from these inspections. This study contributes to improve the quality of the dimensional measurements by defining experimental procedures, applicable to the optical systems used in CCTV inspection. The paper describes the European normative framework for these inspection activities and proposes approaches aiming at increasing confidence in the dimensional measurements based on the metrological characterization of the optical systems used, as well as, to establish a traceability chain. Results presented and discussed include the evaluation of measurement uncertainty.</p>

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Section: Resultsmentioning

confidence: 99%

“…The radiometric characterization can be carried out following the EMVA standard guidelines [18]- [19], allowing determining the CCTV camera sensitivity, linearity, noise, dark current, spatial non-uniformity and defecting pixels.…”

Section: Proposed Approachesmentioning

confidence: 99%

Optical metrology applied in CCTV inspection in drain and sewer systems

2020

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“…Initially, a model is required which represents the camera sensor with the associated influencing parameters. For this purpose Jähne [37] and Rosenberger et al [38] introduced the generic black-box camera model which is now incorporated into the EMVA 1288 standard [6]. In their research, they established a series of methods to analyse and visualise particular characteristics of imaging sensors.…”

Section: Sensor and Laser Spot Modelmentioning

confidence: 99%

“…var(θ) ≥ I (θ) −1 (38) In order to illustrate the CRLB results in this paper, they are exemplary calculated for μ p,max and σ g . Then they are plotted with respect to the exposure time and the number of incident photons.…”

Section: Calculation Of Fisher Information and Cramér-rao Boundmentioning

confidence: 99%

Imaging sensor data modelling and evaluation based on optical composite characteristics

Meister

Grundhöfer

Stüve

et al. 2021

Int J Adv Manuf Technol

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Automated Fibre Placement is a common manufacturing technique for composite parts in the aero-space industry. Therefore, a visual part inspection is required which often covers up to 50% of the actual production time. Moreover, the inspection quality of this manual step fluctuates significantly. A camera-based automated inline inspection is capable of increasing the inspection efficiency and accuracy. However, the interpretability of the acquired data strongly depends on the sensor configuration and the inspected material. Thus, this paper introduces methods for modelling and assessing an imaging sensor on the example of a composite material reflecting a spot laser to a camera sensor. In this context, the reflection properties of the material are incorporated into a simulation and validated in comparison to real camera images from the experimental setup. The EMVA 1288 sensor model in combination with the Cramér–Rao lower bound indicates a feasible estimability of the beam propagation, but shows limitations in the predictability of the number of incident photons. The laser spot analysis indicated that the laser spot can deviate from an exact oval shape but its peak value is suitable for robust spot identification in an image. The outlined methodology is also adaptable to other imaging sensors, illumination sources and materials. Thus, the findings can be useful for other fields and manufacturing processes.

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“…Over the past several decades, many imaging sensors based primarily on CCD or CMOS technology were developed. Datasheets provided by developers are usually written on their standards, and no universal figure of merit can be drawn from them for comparison purposes [ 10 ]. Most manufacturers of sensors for industrial cameras do not fully specify their characteristics or apply sophisticated measurement methods, leaving to camera developers ambiguities that arise during camera design and require meticulous checks.…”

Section: Introductionmentioning

confidence: 99%

An Instrument for the Characterization and Calibration of Optical Sensors

Gastasini

Capecci

Lupi

et al. 2021

Sensors

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This paper presents the development of a hardware/software system for the characterization of the electronic response of optical (camera) sensors such as matrix and linear color and monochrome Charge Coupled Device (CCD) or Complementary Metal Oxide Semiconductor (CMOS). The electronic response of a sensor is required for inspection purposes. It also allows the design and calibration of the integrating device to achieve the desired performance. The proposed instrument equipment fulfills the most recent European Machine Vision Association (EMVA) 1288 standard ver. 3.1: the spatial non uniformity of the illumination ΔE must be under 3%, and the sensor must achieve an f-number of 8.0 concerning the light source. The following main innovations have achieved this: an Ulbricht sphere providing a uniform light distribution (irradiation) of 99.54%; an innovative illuminator with proper positioning of color Light Emitting Diodes (LEDs) and control electronics; and a flexible C# program to analyze the sensor parameters, namely Quantum Efficiency, Overall System Gain, Temporal Dark Noise, Dark Signal Non Uniformity (DSNU1288), Photo Response Non-Uniformity (PRNU1288), Maximum achievable Signal to Noise Ratio (SNRmax), Absolute sensitivity threshold, Saturation Capacity, Dynamic Range, and Dark Current. This new instrument has allowed a camera manufacturer to design, integrate, and inspect numerous devices and camera models (Necta, Celera, and Aria).

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EMVA 1288 Camera characterisation and the influences of radiometric camera characteristics on geometric measurements

Cited by 9 publications

References 8 publications

Optical metrology applied in CCTV inspection in drain and sewer systems

Optical metrology applied in CCTV inspection in drain and sewer systems

Imaging sensor data modelling and evaluation based on optical composite characteristics

An Instrument for the Characterization and Calibration of Optical Sensors

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