Visible Wavelength Images Research Articles

Efficient private key generation from iris data for privacy and security applications

Private key generation based on biometric data is gaining popularity in several cryptographic applications. Some key generation approaches using fingerprint and face data are known for this purpose. The existing approaches, in general, follow direct features from raw data, which may have an issue of revealing users’ biometric data. Further, iris biometrics being a better source for stable and secure key generation, is yet to be explored. In this work, an iris biometric-based key generation approach is proposed. In the proposed method, first, an ensemble L0 Gradient Minimization and an edge-preserving filter are used to extract iris structure from the iris images. Secondly, the iris texture data is normalized, and the consistent region is selected based on a novel statistical method. Thirdly, feature vectors are generated using the ensemble local space-filling curve descriptors and their variants. Fourth, a discriminant feature vector is generated using hybrid feature selection and neighbourhood component analysis. Finally, an interval-based encoding scheme is used to generate a key from the discriminant feature vector. To substantiate the efficacy of the proposed approach, extensive experiments have been carried out with near-infrared images, visible wavelength images, at-a-distance, and on-move images. Further, distinctiveness, dissimilarity, randomness, and security analyses have been carried out to validate the resilience of keys against different attacks. More significantly, a unique key can be generated dynamically, that is, from an online image. The proposed approach is applicable to different cryptographic applications, such as data storage security, remote authentication protocol, blockchain system security, etc.

The Apparent Absence of Forward Scattering in the HD 53143 Debris Disk

HD 53143 is a mature Sun-like star and host to a broad disk of dusty debris, including a cold outer ring of planetesimals near 90 au. Unlike most other inclined debris disks imaged at visible wavelengths, the cold disk around HD 53143 appears as disconnected “arcs” of material, with no forward-scattering side detected to date. We present new, deeper Hubble Space Telescope Imaging Spectrograph coronagraphic observations of the HD 53143 debris disk and show that the forward-scattering side of the disk remains undetected. By fitting our KLIP-reduced observations via forward modeling with an optically thin disk model, we show that fitting the visible wavelength images with an azimuthally symmetric disk with unconstrained orientation results in an unphysical edge-on orientation that is at odds with recent ALMA observations, while constraining the orientation to that observed by ALMA results in nearly isotropically scattering dust. We show that the HD 53143 host star exhibits significant stellar variations due to spot rotation and revisit age estimates for this system.

Automated cataract disease detection on anterior segment eye images using adaptive thresholding and fine tuned inception-v3 model

Early detection of cataracts plays a vital role in ensuring the prevention of vision loss. This paper aims to propose an algorithm that will act as an assistive measure in the process of automating cataract disease detection. The majority of the existing works are focused on the utilization of either fundus images, slit lamp images, or visible wavelength images captured using a DSLR camera. The novelty of this proposed algorithm is the capability to deliver equally accurate and precise performance using both normally captured visible wavelength images as well as medically captured anterior segment images which can, in turn, prove to be cost-effective as well. The image pre-processing techniques particularly adaptive thresholding hereby employed provides fast and accurate results on the input dataset fed to the CNN model which in turn is a fine-tuned version of Inception-v3. Here the training of the model has been done using visible wavelength images whereas the validation testing has been done using the anterior segment eye images medically obtained from a hospital. The proposed image pre-processing technique along with the model architecture ensures the achievement of a high classification accuracy of about 95%. Since the model deals with the examination of the anterior segment of the image, cases concerning nuclear cataract, cortical cataract, or a hybrid case involving the detection of both the aforementioned cataract types lie under the range of detection of our system.

Dedicated hardware architecture for localizing iris in VW images

This study presents dedicated hardware for iris localization that can be used as a coprocessor in the development of real-time and low-cost embedded iris biometric systems. Though the hardware architecture is described for iris localization in the visible wavelength (VW) images, the concept used can be applied to near infrared (NIR) images as well. In general, the architecture can be used for a class of iris localization algorithms based on the edge-map generation and circular Hough transform (CHT). The architecture presented here generates the edge-maps for limbic and pupil boundary detection using median filtering followed by Sobel edge detection; however, an additional reflection removal module is used for pupil boundary detection. Further, the CHT hardware module detects circle in each edge-map. The proposed architecture was implemented in programmable logic of the Zynq-7000 SoC device from Xilinx. This hardware implementation gives an iris localization accuracy of 98.43% and average processing time of 5.148 ms for UBIRIS.v1 VW database images (200 × 150 pixel). The algorithm used is suitable for less unconstrained and frontal-view iris images captured with subjects’ active participation; however, the images may contain non-ideal issues such as reflection and occlusion by eyelids and eyelashes.

Characterization of material around the centaur (2060) Chiron from a visible and near-infrared stellar occultation in 2011

ABSTRACT The centaur (2060) Chiron exhibits outgassing behaviour and possibly hosts a ring system. On 2011 November 29, Chiron occulted a fairly bright star (R ∼ 15 mag) as observed from the 3-m NASA Infrared Telescope Facility (IRTF) on Mauna Kea and the 2-m Faulkes Telescope North (FTN) at Haleakala. Data were taken as visible wavelength images and simultaneous, low-resolution, near-infrared (NIR) spectra. Here, we present a detailed examination of the light-curve features in the optical data and an analysis of the NIR spectra. We place a lower limit on the spherical diameter of Chiron's nucleus of 160.2 ± 1.3 km. Sharp, narrow dips were observed between 280 and 360 km from the centre (depending on event geometry). For a central chord and assumed ring plane, the separated features are 298.5–302 and 308–310.5 km from the nucleus, with normal optical depth ∼0.5–0.9, and a gap of 9.1 ± 1.3 km. These features are similar in equivalent depth to Chariklo's inner ring. The absence of absorbing/scattering material near the nucleus suggests that these sharp dips are more likely to be planar rings than a shell of material. The region of relatively increased transmission is within the 1:2 spin-orbit resonance, consistent with the proposed clearing pattern for a non-axisymmetric nucleus. Characteristics of possible azimuthally incomplete features are presented, which could be transient, as well as a possible shell from ∼900–1500 km: future observations are needed for confirmation. There are no significant features in the NIR light curves, nor any correlation between optical features and NIR spectral slope.

IRIS Recognition using Hough Transform

In most iris identification systems, the complete image acquires constraints are understood. These Constrain include near-infrared (NIR) illumination to release the iris texture and close distance from the capturing device. In recent advances to different illumination technologies introduced in images captured in the environment. This environment includes a visible wavelength (VW) light source at-a-distance over the close distance from the capturing device. For accurate Iris identification at-a-distance, eye images require improvement of effective strategies, while setting the light source at a distance from the planar view of the iris. Effectively performing feature extraction technique for Near-Infrared and Visible wavelength images, that were collected in an uncontrolled stage. The identification of iris accuracy on the publicly available databases was then measured. This paper presents a preprocessing of Iris Recognition using Hough Transform (HT) for Iris Area of interest (AOI) and rubber-sheeting the model captured using linear stretching and rotation for normalization. The HT is used to filter and contrast stretch the iris regions from multispectral iris images. A basic purpose of this research is to envelop a design and implement IRIS-recognition at a distance (IAAD) by adopting a frequency and wavelength-based Hough transform for accurate feature selection [1][2]. The proposed method is described as follows: Initially, the input iris image will be subjected to pre-processing while extracting features with differences from local extrema and maxima conditions, using a regular shape filling Hough transform [3][4]. The iris localization and detection consists of a hill climbing segmentation approach that is based on geometric shape Hough measure. Proposed in comparison to the contemporary

A hybrid method for accurate iris segmentation on at-a-distance visible-wavelength images

This work describes a new hybrid method for accurate iris segmentation from full-face images independently of the ethnicity of the subject. It is based on a combination of three methods: facial key-point detection, integro-differential operator (IDO) and mathematical morphology. First, facial landmarks are extracted by means of the Chehra algorithm in order to obtain the eye location. Then, the IDO is applied to the extracted sub-image containing only the eye in order to locate the iris. Once the iris is located, a series of mathematical morphological operations is performed in order to accurately segment it. Results are obtained and compared among four different ethnicities (Asian, Black, Latino and White) as well as with two other iris segmentation algorithms. In addition, robustness against rotation, blurring and noise is also assessed. Our method obtains state-of-the-art performance and shows itself robust with small amounts of blur, noise and/or rotation. Furthermore, it is fast, accurate, and its code is publicly available.

Efficient features for smartphone-based iris recognition

Iris recognition has widely been used in personal authentication problems. Recent advances in iris recognition through visible wavelength images have paved the way for the use of this technology in smartphones. Smartphone-based iris recognition can be of significant use in financial transactions and secure storage of sensitive information. This paper presents a hybrid representation scheme for iris recognition in mobile devices. The scheme is called hybrid because it firstly makes use of Gabor wavelets to reveal the texture present in the normalized iris images, and then extracts statistical features from different partitions of Gabor-processed images. The standard mobile-iris database, called MICHE, is used for investigating the performance of the proposed approach. The comparison of the proposed approach with other widespread iris recognition approaches proves its efficacy.

A stellar occultation by Vanth, a satellite of (90482) Orcus

A stellar occultation by the large trans-Neptunian object (90482) Orcus was predicted to occur on 2017 March 07. Observations were made at five sites in North and South America: the 0.6-m Astronomical Telescope of the University of Stuttgart (ATUS) at Sierra Remote Observatories, California; Las Cumbres Observatory's 1-m telescope at McDonald Observatory, Fort Davis, Texas (ELP); NASA's 3-m InfraRed Telescope Facility (IRTF) on Mauna Kea, Hawai'i; the 0.6-m Southeastern Association for Research in Astronomy (SARA-CT) telescope at Cerro Tololo, Chile; and the 4.1-m Southern Astrophysical Research (SOAR) telescope on Cerro Pachón, Chile. High-speed, visible-wavelength images were taken at all sites, in addition to simultaneous K-band images at the IRTF. Solid-body occultations were observed from two sites. Post-event reconstruction suggested an occultation of two different stars observed from two different sites. Follow-up, speckle imaging revealed a second star, which verified that the occulting body in both cases was Orcus’ satellite, Vanth. The two single-chord detections, with an anomalously large timing delay in one chord, have lengths of 291 ± 125 km and 434.4 ± 2.4 km. The observations, combined with a non-detection at a nearby site, allow a tight constraint of 443 ± 10 km to be placed on Vanth's size (assuming it is spherical). A 3-σ upper limit of 1–4 μbar (depending on constituent) is found for a global Vanth atmosphere. The immersion and emersion profiles are slightly different, with atmospheric constraints 40% higher on immersion than on emersion. No rings or other material were detected within ten thousand kms of Vanth, and beyond 8010 km from Orcus, to the tightest optical depth limit of ∼0.1 at ∼5 km scale. The occultation probed as close as 5040 km from Orcus, placing an optical depth limit of ∼0.3 at ∼5 km scale on any encircling material at that distance.

Attention guided U-Net for accurate iris segmentation

Iris segmentation is a critical step for improving the accuracy of iris recognition, as well as for medical concerns. Existing methods generally use whole eye images as input for network learning, which do not consider the geometric constrain that iris only occur in a specific area in the eye. As a result, such methods can be easily affected by irrelevant noisy pixels outside iris region. In order to address this problem, we propose the ATTention U-Net (ATT-UNet) which guides the model to learn more discriminative features for separating the iris and non-iris pixels. The ATT-UNet firstly regress a bounding box of the potential iris region and generated an attention mask. Then, the mask is used as a weighted function to merge with discriminative feature maps in the model, making segmentation model pay more attention to iris region. We implement our approach on UBIRIS.v2 and CASIA.IrisV4-distance, and achieve mean error rates of 0.76% and 0.38%, respectively. Experimental results show that our method achieves consistent improvement in both visible wavelength and near-infrared iris images with challenging scenery, and surpass other representative iris segmentation approaches.

Daytime atmospheric plume opacity measurement using a camcorder

Abstract Digital Optical Method (DOM) software, developed earlier to measure atmospheric plume opacity with digital still cameras, was tested with a camcorder, which captures digital images (as video frames) in visible light wavelengths at 30 Hz. The effect of contrast between two backgrounds when using DOM contrast model was demonstrated through the use of different pixel value measurement wavelengths and different background pairs. Unique contributions presented here are: (1) the camcorder is within the United States Environmental Protection Agency Method 9 individual and average opacity error limits, for black and white plumes with opacity values between 0% and 90%, while enabling real-time opacity measurements; (2) increasing contrast between two backgrounds decreases the opacity measurement error and uncertainty, with all measurements within individual and average opacity error limits for contrast parameter ≥ 0.92; and (3) background choice affects the opacity measurement uncertainty more than camcorder calibration and number of pixels sampled for tested conditions. These contributions are important because they are the first demonstration and evaluation of applying digital image analysis with camcorders to quantify atmospheric plume opacity. Moreover, the results show that obtaining higher contrast between two backgrounds is the most important factor for reducing error in plume opacity measurements to meet acceptable performance criteria. This knowledge increases the reliability of image analysis to provide a low-cost and real-time monitoring method for quantifying atmospheric plume opacity.

The Search for Active Marsquakes Using Subpixel Coregistration and Correlation: Best Practice and First Results

AbstractThe state of seismic activity on Mars is currently unknown. On Earth, coseismic displacement has been observed using visible wavelength images and subpixel coregistration and correlation techniques. We apply this method to Mars with the COSI‐Corr (Co‐registration of Optically Sensed Images and Correlation) software package using High‐Resolution Imaging Science Experiment (HiRISE) images, focusing on part of the Cerberus Fossae fault system. We derive best practices for applying this method to the study of coseismic displacements on Mars. Using a time series of eight overlapping HiRISE images, we achieve pixel coregistration with a mean accuracy of about 1/50 of a pixel. We see no clear evidence for coseismic displacement in this region during a time period of over 8 years. One possible displacement signal (1–2 m of west‐east displacement over a length scale of about 50 m) that has similarities to terrestrial coseismic deformation was dismissed as the result of incomplete correction of steep topography during the coregistration stage. Ancillary observations of recurring slope lineae (RSL) activity in the surrounding fault system offer no supporting evidence for the occurrence of coseismic displacement but do seem to suggest RSL activity that does not fit into previous seasonal timescales. Although it is unlikely that we have observed coseismic displacement in our study area during this time period, the best practice method and the accuracy of our results offer encouragement for future studies. HiRISE, Context Camera, and Color and Stereo Surface Imaging System images can be used to complement and independently verify in situ seismic observations by the InSight (Interior Exploration using Seismic Investigations, Geodesy, and Heat Transport) lander or source location changes from the ExoMars Trace Gas Orbiter spacecraft.

Integrated Approach for Sclera Recognition and Eye Gaze Detection

In this paper we proposed unique technique which is adaptive to noisy images for eye gaze detection as processing noisy sclera images captured at-a-distance and on-the-move has not been extensively investigated. Sclera blood vessels have been investigated recently as an efficient biometric trait. Capturing part of the eye with a normal camera using visible-wavelength images rather than near infrared images has provoked research interest. This technique involves sclera template rotation alignment and a distance scaling method to minimize the error rates when noisy eye images are captured at-a-distance and on-the move. The proposed system is tested and results are generated by extensive simulation in java.

NIR and VW iris image recognition using ensemble of patch statistics features

A novel iris recognition system is proposed in this paper. The proposed system is able to handle various challenging issues which may occur during image acquisition in near-infrared and/or visible wavelength lights under constrained and less-constrained environments. The proposed system demonstrates great perseverance for recognizing subjects in both stable and adverse situations. During recognition, the system performs image preprocessing, feature extraction, and classification tasks. During preprocessing, an annular iris portion is segmented out from an input eyeball image, and for this, two different segmentation approaches: one for near-infrared images and another for visible wavelength images, have been proposed. A novel patch-based histogram-type feature (ensemble of patch statistics) which adopts a statistical approach of texture analysis is employed during feature extraction. For the proposed system, the extensive experimental results have been demonstrated using ten benchmark iris databases, namely MMU1, UPOL, IITD, UBIRIS.v1, CASIA-Interval-v3, CASIA-Iris-Twins, CASIA-Iris-Thousand, CASIA-Iris-Distance, CASIA-Iris-Syn, and UBIRIS.v2. The performance of the proposed system is compared with the state-of-the-art methods on these databases and the comparisons show significant out-performance on the competing methods.

The design and development of low- and high-voltage ASICs for space-borne CCD cameras

The CCD remains the pre-eminent visible and UV wavelength image sensor in space science, Earth and planetary remote sensing. However, the design of space-qualified CCD readout electronics is a significant challenge with requirements for low-volume, low-mass, low-power, high-reliability and tolerance to space radiation. Space-qualified components are frequently unavailable and up-screened commercial components seldom meet project or international space agency requirements. In this paper, we describe an alternative approach of designing and space-qualifying a series of low- and high-voltage mixed-signal application-specific integrated circuits (ASICs), the ongoing development of two low-voltage ASICs with successful flight heritage, and two new high-voltage designs. A challenging sub-system of any CCD camera is the video processing and digitisation electronics. We describe recent developments to improve performance and tolerance to radiation-induced single event latchup of a CCD video processing ASIC originally developed for NASA’s Solar Terrestrial Relations Observatory and Solar Dynamics Observatory. We also describe a programme to develop two high-voltage ASICs to address the challenges presented with generating a CCD’s bias voltages and drive clocks. A 0.35 μm, 50 V tolerant, CMOS process has been used to combine standard low-voltage 3.3 V transistors with high-voltage 50 V diffused MOSFET transistors that enable output buffers to drive CCD bias drains, gates and clock electrodes directly. We describe a CCD bias voltage generator ASIC that provides 24 independent and programmable 0–32 V outputs. Each channel incorporates a 10-bit digital-to-analogue converter, provides current drive of up to 20 mA into loads of 10 μF, and includes current-limiting and short-circuit protection. An on-chip telemetry system with a 12-bit analogue-to-digital converter enables the outputs and multiple off-chip camera voltages to be monitored. The ASIC can drive one or more CCDs and replaces the many discrete components required in current cameras. We also describe a CCD clock driver ASIC that provides six independent and programmable drivers with high-current capacity. The device enables various CCD clock parameters to be programmed independently, for example the clock-low and clock-high voltage levels, and the clock-rise and clock-fall times, allowing configuration for serial clock frequencies in the range 0.1–2 MHz and image clock frequencies in the range 10–100 kHz. Finally, we demonstrate the impact and importance of this technology for the development of compact, high-performance and low-power integrated focal plane electronics.

Maritime domain awareness with commercially accessible electro-optical sensors in space

Comprehensive maritime domain awareness includes detection, tracking, and identification of vessels, and we describe work concerned with the detection and tracking elements of this problem. Millions of maritime vessels operate without the means for their positions to be independently tracked, presenting a problem for safety and security of life at sea. To date, visible wavelength imaging from space has been of limited use for vessel detection and tracking due to poor area coverage provided by individual satellites. This situation is now changing. We present a survey of currently operating spacecraft carrying electro-optical imagers offering adequate imaging resolution and commercial data availability. We model the coverage provided by 54 satellites and 85 sensors over a target area to assess the value of these assets for space-based maritime domain awareness. The results show that useful levels of coverage can now be obtained through the collective observations of existing spacecraft, although on-board resources will limit the amount of imagery that can be acquired. The launch of large numbers of high-resolution imaging nanosatellites produced by private companies will improve this coverage, and the increasing capability of small satellite platforms offers the possibility of a dedicated Electro-Optical Space-Based Maritime Domain Awareness constellation that can realise the full benefit of the concept. We propose a cooperative approach, based on cloud computing and crowdsourcing philosophies, to the operation of the ground segment and the sharing and analysis of image data, to create an effective constellation of satellites and associated data handling infrastructure that can be used to enhance maritime security, and improve the safety of lives at sea.

Evidence for an explosive origin of central pit craters on Mars

Kilometer-scale pits are nested in the centers of many impact craters on Mars as well as on icy satellites. They have been inferred to form in the presence of a water–ice rich substrate; however, the process(es) responsible for their formation is still debated. Previous models invoke origins by either explosive excavation of potentially water-bearing crustal material, or by subsurface drainage of meltwater and/or collapse. If explosive excavation forms central pits, pit-derived ejecta should be draped around the pits, whereas internal collapse should not deposit significant material outside pit rims. Using visible wavelength images from the Mars Reconnaissance Orbiter (MRO) Context Camera (CTX) and High Resolution Imaging Science Experiment (HiRISE) instruments and thermal infrared images from the Odyssey Thermal Emission Imaging System (THEMIS) instrument, we conducted a survey to characterize, in detail, the global population of central pits in impact craters ⩾10km in diameter. We specifically examined the morphology and thermophysical characteristics of the pits for evidence of pit ejecta. Our analysis of thermal images suggests that coarse-grained materials are distributed proximally around many central pits on the floors of their host craters. The decrease in average grain size with distance from pit rims is consistent with pit-derived ejecta. These observations and interpretations better support an explosive origin for central pits on Mars than they do an origin of subsurface meltwater drainage and collapse of the overlying substrate. A major weakness to previous explosive central pit formation models is the inability for them to form pits late enough in the impact process to be preserved. To address this, we present an alternative “melt contact model” where a central uplift brings ice-bearing substrate into contact with impact melt to generate steam explosions and excavate central pits during the impact modification stage. Theoretical calculations show that more than enough thermal energy is available via impact melt from the host crater to form central pits by steam explosions, and such explosions would require only a modest amount (2–6% by volume) of uplifted water–ice. We therefore propose that central pits on Mars could have formed explosively by the interaction of impact melt and subsurface water–ice.

Iris segmentation for visible wavelength and near infrared eye images

State-of-the-art iris segmentation algorithms exhibit poor performance for non-ideal data, which is mainly because of the noise such as low contrast, non-uniform illumination, reflections, and among others. To address this issue, a robust iris segmentation scheme is proposed that includes the following: First, a set of the Seed-pixels in a preprocessed eye image is marked adaptively. Next, a two-fold scheme based on a Circu-differential accumulator (CDA) and gray statistics is adopted to localize coarse iris region robustly. Notably, the proposed CDA has close resemblance with the Hough transform; however, it consumes relatively less memory and is free from thresholding as well. Similarly, pupillary boundary is localized, which is verified through an intensity test as well. Next, a refine estimate for the limbic boundary is extracted. After that, iris boundaries are regularized using the Fourier series. Finally, the eyelids are localized using a Para-differential accumulator (PDA), and eyelashes and reflections are also localized adaptively in the polar form of iris. Experimental results on the near infrared (NIR) and visible wavelength (VW) iris databases show that the proposed technique outperforms contemporary approaches.

Observations of a successive stellar occultation by Charon and graze by Pluto in 2011: Multiwavelength SpeX and MORIS data from the IRTF

Pluto’s lower atmosphere has been observed to evolve since the first definitive occultation detection in 1988. Possibilities for explaining the lower atmospheric structure include a steep thermal gradient and/or extinction, the latter of which can be characterized as a dependence between occultation flux and wavelength. On 2011 June 23, a 14.43 UCAC magnitude star (R=13.64) was occulted by Pluto as observed from multiple sites. Observations made at NASA’s 3-m Infrared Telescope Facility (IRTF) on Mauna Kea, Hawai’i, showed a full occultation of the star by Charon followed by an atmospheric graze by Pluto. Data were taken simultaneously in visible-wavelength images and low-resolution, near-infrared spectra. This dataset is unique in that (i) the double occultation allows astrometric measurements for Pluto and Charon as well as accurate calibration of the Pluto light curve, and (ii) the wavelength-resolved data serve as a test for atmospheric extinction. The graze reached a minimum normalized flux level of roughly 0.35, serving primarily as a probe of Pluto’s upper atmosphere (which is typically defined to be above half-light level in occultation light curves). However, the light curve is well fit by atmospheric models with a power-law thermal gradient, a clear upper atmosphere, and haze in the lower atmosphere. We find a negative dependence between flux and wavelength in the deepest part of Pluto’s atmosphere probed by the graze and in a spike during emersion. A simple extinction model for spherical, μm-sized tholins matches the observed spectral trends. While the atmospheric fits cannot rule out a clear atmosphere having a steep thermal gradient at the bottom, the flux-wavelength dependence and the feasibility of our particle-scattering fits suggest that Pluto’s lower atmosphere contained haze in 2011. These results provide an important link in monitoring Pluto’s dynamic atmosphere.

Optimizing SIFT for Matching of Short Wave Infrared and Visible Wavelength Images

The scale invariant feature transform (SIFT) is a widely used interest operator for supporting tasks such as 3D matching, 3D scene reconstruction, panorama stitching, image registration and motion tracking. Although SIFT is reported to be robust to disparate radiometric and geometric conditions in visible light imagery, using the default input parameters does not yield satisfactory results when matching imagery acquired at non-overlapping wavelengths. In this paper, optimization of the SIFT parameters for matching multi-wavelength image sets is documented. In order to integrate hyperspectral panoramic images with reference imagery and 3D data, corresponding points were required between visible light and short wave infrared images, each acquired from a slightly different position and with different resolutions and geometric projections. The default SIFT parameters resulted in too few points being found, requiring the influence of five key parameters on the number of matched points to be explored using statistical techniques. Results are discussed for two geological datasets. Using the SIFT operator with optimized parameters and an additional outlier elimination method, allowed between four and 22 times more homologous points to be found with improved image point distributions, than using the default parameter values recommended in the literature.