Improved aperture for modulation transfer function measurement of detector arrays beyond the Nyquist frequency

The design of an aperture for the generation of laser speckle with a flat power spectrum covering a wide band of the measurement spatial-frequency range is presented. This aperture allows for the measurement of modulation transfer function (MTF) from zero to twice the Nyquist frequency of a two-dimensional detector array. This design mitigates many of the measurement problems inherent in other aperture designs. The MTF measurement of a CCD detector array is used to demonstrate the measurement technique and illustrate the advantages of the new aperture design

Recent advances in the modulation transfer function testing of detector arrays

The increased complexity of imaging sensors and total number of discrete detector sites has challenged traditional testing methods. The importance of reliable modulation transfer function testing of imaging sensors with high uncertainty has consequently grown more difficult. In this paper we demonstrate the design of an aperture for the generation of laser speckle with a flat power spectrum covering a wide-band of the measurement spatial frequency range. This aperture allows for the measurement of modulation transfer function (MTF) from zero to twice the Nyquist frequency of a twodimensional detector array. This design mitigates many of the measurement issues inherent in other aperture designs. The MTF measurement of a charge-coupled device (CCD) detector array is used to demonstrate the measurement technique and illustrate the advantages of the new aperture design. © 2008 Copyright SPIE - The International Society for Optical Engineering

Microlens diffusers for efficient laser speckle generation

Laser Speckle is the optical phenomena resulting from the random interference of coherent light. This phenomenon can be utilized to measure the Modulation Transfer Function (MTF) of detector arrays. Common devices used for speckle generation, such as integrating spheres and ground glass, suffer from low efficiencies less than 20%. Microlens diffusers are shown to be more efficient alternatives for speckle generation. An analysis of the statistical behavior of microlens diffusers is presented with emphasis on their application to MTF testing of detector arrays in the visible spectrum

Recent Advances In The Modulation Transfer Function Testing Of Detector Arrays

The increased complexity of imaging sensors and total number of discrete detector sites has challenged traditional testing methods. The importance of reliable modulation transfer function testing of imaging sensors with high uncertainty has consequently grown more difficult. In this paper we demonstrate the design of an aperture for the generation of laser speckle with a flat power spectrum covering a wide-band of the measurement spatial frequency range. This aperture allows for the measurement of modulation transfer function (MTF) from zero to twice the Nyquist frequency of a twodimensional detector array. This design mitigates many of the measurement issues inherent in other aperture designs. The MTF measurement of a charge-coupled device (CCD) detector array is used to demonstrate the measurement technique and illustrate the advantages of the new aperture design. © 2008 Copyright SPIE - The International Society for Optical Engineering

Holographic Elements For Modulation Transfer Function Testing Of Detector Arrays

A holographic technique is presented that increases the flux-transfer efficiency of laser speckle generation by a factor of 100 over the integrating sphere method. This makes a wider range of low-power lasers usable for the speckle MTF test, method, and increases the number of wavelengths at which the test can be applied

Distance Education Technology: New Model For Lecture Recording And Distribution

The College of Engineering and Computer Science at the University of Central Florida (UCF) has been a leader in distance learning for the last 25 years. This was initiated by the Florida legislature by the creation of the Florida Engineering Education Delivery System. The goal of this system was to promote engineering education in the State of Florida. The early delivery system utilized video tapes and transitioned to the internet in 2000. In spring 2007, the College of Engineering and Computer Science purchased a software based lecture recording and delivery system, Tegrity Campus 2.0. This system was used to completely replace all existing recording hardware and software. The system launch included 90 faculty delivering 100 courses to 2300 engineering students. This paper addresses a new model for recording and distributing engineering lectures on the internet. First, we describe our transition from the old to the new model for distance education. Second, a comparison of the implementation requirements, the advantages and disadvantages of both models are presented. Finally, in addition to any difficulties encountered while launching the new system and how they were solved

Random Targets For Modulation Transfer Function Testing

Tests for modulation transfer function (MTF), particularly for staring systems, are affected by the position of the test target with respect to the rows and columns of the detector array. To alleviate the position-dependent nature of the measurement, we have developed a target that uses random patterns of known spatial-frequency content. In this way a phase-averaged MTF is measured, which is indicative of field performance on natural scenes

Use Of Narrowband Laser Speckle For Mtf Characterization Of Ccds

This paper presents a method for measuring the modulation transfer function (MTF) of a detector array from zero frequency to twice the Nyquist frequency. The equipment is simple and requires no complex optical components. Also, the use of laser speckle circumvents the problems inherent with traditional methods of MTF testing where the phase of the test target with respect to the sampling grid affects the observed contrast. The MTF measured with this method is compared to the MTF measured using sine targets. The results of the two methods agree to within 2%

Point-Spread Function And Mtf Characterization Of The Kinetic-Kill-Vehicle Hardware-In-The-Loop Simulation (Khils) Infrared-Laser Scene Projector

A Scophony Infrared Scene Projector (IRSP) is being used at Wright Laboratories Armament Directorate, Guided Interceptor Technology Branch, Eglin AFB, to evaluate thermal-imaging guidance systems. This hardware-in-the-loop testing system reduces the number of necessary field trials and has potential for in-laboratory simulation where the performance of entire seeker systems can be analyzed. The performance of an optical system, in terms of such characteristics as wavefront error, resolution, and transfer factor, can be measured with knowledge of the system MTF and PSF performance. A slow-scan calibration system was used to measure an image plane of the IRSP under three separate configurations of the system. MTFs and PSFs were derived for the IRSP without the use of the scatter screen, with the scatter screen in place, and with the scatter screen rotating