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    A Novel Multi-frame Super Resolution algorithm for

    Surveillance Camera Image Reconstruction  Aunsia Khan, Muhammad Aamir Khan,Faisal Obaid, Sultanullah Jadoon,

     Mudassar Ali Khan and Misba Sikandar{aunsiakhan,mudaser,aamir,sultan,misbasikandar}@uoh.edu.pk, [email protected]

     Department of Information Technology, University of Haripur, Khyber Pakhtunkhwa, Pakistan 

     Abstract  —  This paper gives a loom towards the  

    growing spatial resolution necessary to beat the limitations

    of the imaging technology in surveillance and security

    disciplines. It has been observed that metropolis cities

    worldwide invest huge sum of money in surveillance

    camera system but few are closely observing the benefits

    and the costs of those investments and to measure the

    overall impact of surveillance cameras on crime rates. The

    low resolution coupled with poor quality optics is not be

    enough to identify the subject of interest in crowd, from a

    distance, in bad weather and any other limiting factor. In

    this paper we have introduced multi-frame super-

    resolution technique that does not require explicit motion

    estimation and will be useful for producing imagery

    evidence that the police might reasonably accept as proof

    of someone's identity. Mostly the research is done in this

    area by taking a SR image and then after adding their own

    noise patterns where as our algorithm are working on

    actual LR images of surveillance camera and getting a SR

    image while removing the original blur and noise. Our

    algorithm requires the training set of Low resolution (LR)

    images from a still camera to produce High resolution

    (HR) image data and enhances it using anisotropic

    Diffusion and De-noising. In the image based

    representations, this technique of super resolution providesa great step towards resolution independence. The

    application of this method was successfully demonstrated

    for the restoration from a short low resolution set of

    images into a super resolved image. This super resolution

    algorithm works best when the Diffusion is applied and

    noise reduction filters are applied.

     Keywords —Super Resolution, Surveillance camera

    images, Multi frame super resolution, Gray images, Low

    Resolution images, Training Set.

    I. INTRODUCTION

    Image-based models intended for computer graphics

    are resolution dependent, they cannot be zoomed a lot

     beyond the pixel resolution on which they were sampled

    at without causing degradation of overall quality. The process of obtaining a high resolution image by increasing the number of pixels is known as Super

    resolution. Vande walle et al defined higher resolution

    image as an image constructed by up- sampling and

    interpolation having more resolution and large number

    of pixels than actual low resolution image but have no

    extra details. Capel's proposed definition of resolution

    enhancement depicts that the low resolution image

    should result in an improved detailed contents in super

    resolution image by restoring the high frequency

    contents. Which causes the overall increase in the

    number of pixels [10]. 

    Super  

    Resolution image reconstruction (SRIR) is one of

    the capable techniques of digital image processing in

    which challenges are made by reconstructing a HighResolution imagery by blending some of the information

    enclosed inside countable numbers of under sampled

    low-resolution images of a particular scene. This

    technique engage many groups by filtering out the blur

    and noise and Up sampling the under sampled images.

    In contrast with diverse image enhancement techniques,

    SRIR technique filter outs the distortions and increasing

    their spatial resolution can enhance the worth of such

    low resolution and under sampled images [1]. Two

    approaches are used to perform super-resolution

    enhancement: that are single frame and multi-frame

    enhancement. Since low resolution images inherently

    contain less information than higher resolution images,the process of constructing high resolution images form

    an input low resolution images requires the missing high

    resolution data to be calculated. 

    The target of SRIR method is to recuperate an image of

    high resolution from low resolution images from a

    surveillance camera provided as an input. Two families

    of methods are used to classify the SR i.e. i) Classical

    multiple image super resolution and ii) Super resolution

    Based on Example. In the classical method (e.g., [12, 5,

    8]) a group of images of a stationary scene having low-

    resolution are taken. All of the low resolution images

    inflict a set of linear constraints on the unidentified highresolution intensity values. If considerable number of

    low-resolution images are taken from the source, then

    high resolution image can easily be reconstructed. 

    978-1-4799-7620-1/15/$31.00 ©2015 IEEE

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    In this paper we focus on multi-frame image

    reconstruction in which LR images are captured

    simultaneously by a surveillance camera. As one of

    constrain with image reconstruction is the missing data.

    So in the multi-frame super-resolution reconstruction,

    Observed images are registered to a specific high

    resolution reference frame in order to formulate the

    fusion problem.

    The major processing steps that characterize the Super

    resolution consist of these following steps: 1.

     

    Low Resolution images acquisition: LR images are

    acquired from the same scene with non-integer (in terms

    of inter-pixel distances) geometric displacements

     between any two of the images.

    2. Motion compensation and Image registration: For the

    reference to high resolution desirable grid, the sub-pixel

    geometric transformation is estimated for every source

    image.

    3. High resolution image reconstruction: constructing a

    high resolution output image as a solution to the actual

     problem.

    4. 

     Noise Reduction: Reducing blur and noise from the

    final image.

    One would expect that the affluence of the real- world

    images seem difficult to capture analytically. This

    encourage an approach based on learning: that is; in a

    training set, The pixel details of different images at a

    low resolution are learnt; then the details of final image

    are predicted based on the learned relationships. For the

     past several years [2, 6], researchers have been

    exploring this approach for enlarging images. To

    motivate why this approach should work at all, we notedthat a set of completely random variables have much

    high variability as compared to the set of image pixels.

    Many research studies have been conducted on

    mammalian visual system for their early processing

    stages [4, 15]. We take advantage of these regularities of

    registration in our algorithms, as we use multiple images

    of one scene, with a still camera, to create an image

    having information more visible then LR images.

    Correct high resolution images cannot be generated

    without a specific training data set. 

    II. ALGORITHM

    CONCEPTUAL IMAGE RESAMPLING

    After reading over the different approaches to perform

    super-resolution, we have decided to focus on multi-

    frame. We selected the multi frame approach because

    we believe it will produce more robust results above

    wider collection of input images. One of the main

    limitations of the single-frame approach is that the

     process will only be effective if the database contains a

    high resolution image which is similar to the image

    which is trying to be enhanced. The multi-frame

    approach on the other hand uses the data which is

    contained in the multiple input frames to interpolate the

    HR image pixel values, this allows the multi-frame

    approach to be applied to any input image, even if a

    similar image was not used during the design of the

    algorithm. 

    At first, as we don't have high resolution data so this

    task may seem impossible. However, we know that the

    edges of the low resolution images should be kept sharp

    in the next resultant resolution level. It is extremely

    difficult to estimate the arbitrary motion without

    guarantee of the estimators performance in the image of

    real world scenes. The Super resolution performance can

    have disastrous implications if the motion estimation is

    incorrect. 

    We aim of generating visually plausible details of

    images e.g. sharp edges and credible texture. The set ofdata is then used to create a new image having increased

    number of pixels and, on the same time, increase in

    resultant image size.

    This paper is to be considered of having the following

    steps: 1.

     

    Set of low resolution images captured via still

    Surveillance camera.

    2. 

    Mapping pixels of each image of low resolution

    to a grid of high resolution.

    Fig. 1. LR images to HR image

    3.  Anisotropic diffusion applied to the HR image.

    4.   Noise Reduction using Noise Reducing Filter.

    III. IMPLEMENTATION

     A. Generation of Training set  We started the generation of training set by collecting

    low resolution images and arranged the images that we

     process all in way for up gradation that we planned. On

    average, low resolution image with original number of

     pixels is created by sub-sampling and blurring. But we

    collected a cluster of same low resolution images to

    reconstruct an up-graded image.

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    Fig. 2. Single LR image 

     B. Mapping LR pixels to HR grid  We apply an initial step of mapping t

    resolution image. We needed to store t

    values of different low resolution imag 

    true image of high resolution. We suphaving grids as the number of pixels

    The size of each HR grid be the same

    number of LR images used. We put al

    LR images in the HR grid respectivel

    figure 

    Fig. 3. LR image to HR grid 

    We want to store each pixel that corr 

     possible pixel of the low-resolution

     pixels are taken from set of 25 image

    shown in fig. (3) whereby interlacing

    we get that the desired resolution is o

     perfect reconstruction is guaranteed.

    camera resolution, we sample using a

    grid. We restricted ourselves to reaso

    of the image, there is still a large numb

    that we have to stock up, and therefo

    generally applicable training sets. Fig.

    image which is created by the said mAs per our believe, for the prediction o

     present in the original image, the co

    resolution image with highest resolu

    important role.

    he pixels of low-

    he different pixel

    s to form the 

     pose a HR imagein the LR image.

    size as that of the

    l the pixels of the

    , as shown in the

    esponds to every

    image; here the

    s, respectively as

    the four images,

     btained, and thus

    Due to limited

    n insufficient 2D

    able information

    er of information

    re we formulated

    (4) shows the HR

    apping of pixels.f very fine details

    mponents of low

    ion  play  a  very 

    Fig. 4. Grid of HR image having

    Fig. 5. HR image

    C. Image Enhancement using Diffus We applied anisotropic diffusion o

    image obtained as HR image so th

    mosaic pattern in our resultant im

    diffusion helped in favoring the hig

    the low contrast edge. We believe

    contrast affects the overall relations

    and high resolution image pixels,

    anisotropic diffusion helps in recontrast resultant image of high reso 

    LR images Pixels

    on the LR image and

    t we don’t have the

    ge. The anisotropic

    contrast edge over

    that the local image

    hip between the low

    and essentially the

    taining the overalllution. 

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    Fig. 6. Diffused LR image 

    Fig. 7. Diffused HR image

      D. Noise Reduction We filter out the Diffused HR image b

    filter in the frequency domain, to reduresultant image. There was no noise i

    the overall degradation is caused onl

    number of pixels. 

    Fig. 8. Applied Filter in Frequency

    a noise reducing

    e the noise in then the LR image;

     because of less

    omain

    Fig. 9. De-Noised Diffused HR i

     

    IV. RESULTS

    Fig. (9) shows results of the algorit

    LR images. Training set wassurveillance camera. A significantly

    resulting image was generated

    acceptable than the original LR

    details and sharp edges were pre

    depicts that our low level training s

     produce an acceptable HR accura

    algorithm interprets that resultant H

    more via diffusion. The fig. (7) sho

    upgrades the HR image. In the mea

    diffused HR image fig. (9) using th

    (8) showed sharper and better res

    LR image in fig. (6). Nonetheless; t

    its best to depict the low-resolution

    high resolution detailed image, fig. ( There is a surprising regularity acro

    a training set made from the imag

    can be used to invent missing detai

    images. While training set of the im

    works best, a training set of generic

    very broad class of inputs. Finally,

     best when the Diffusion is applied

    filters are applied.

    TABLE ISampling rate 10 samp

    Image array dimensions 721 X 5

     No. of Samples 25

    Zoom in Factor 17 X

    Table I enumerate the sampling rate of dat

    samples taken for generating the output an

    which pictures were zoomed for comparison.

    age

    m we applied to our

    aken from a stillclear and acceptable

    that was highly

    images, the image

    erved. The fig. (5)

    t is not sufficient to

    te image data. The

    image is enhanced

    s that the diffusion

    while the de-noised

    filter shown in fig.

    lt than the diffused

    he algorithm proved

    image, resulting in a

    9). 

    ss images, such that

    s of low resolution

    s in many other LR

    ages to be processed

    images can handle a

    the algorithm works

    and noise reduction

    les/sec

    2

    set, the total number of

    d the zoom in factor by

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    TABLE IIFigure Algorithm applied Result

    a No Poor

     b Wiener filter Deficient

    c Bicubic interpolation Good

    d Our algorithm Best

    Table II enlists the application and result of different algorithms when

    applied on the same input and the sub figures shows the zoomed

    images by factor of 17.

    Fig. 10. Comparing our SR with the wiener fi lter and BicubicInterpolation constraints. Note that the bicubic interpolation, when

    applied to LR patches (a) , results in a high-resolution image (c)

    which is sharper and cleaner than the wiener filtered image (b), but is

    not able to recover the fine and plausible details. In contrast, our high-

    resolution image (d) produced these fine details while maintaining the

    edges and line sharpness.

    V. CONCLUSIONS

    In our this paper, we have introduced multi-frame

    super-resolution technique that does not require explicit

    motion estimation and will be useful for producing

    something that the police might reasonably accept as

     proof of someone's identity. Our algorithm was inspired by the algorithms [2, 4]. It is unclear in many studies

    that appear to show success whether surveillance

    cameras had a positive impact in combination with

    improved lighting, or whether the improved lighting

    might accomplish the positive outcome on its own.

    Studies vary on the degree to which they take

    confounding factors into account. The computational

     burden being a difficult task prevents the iteration

    scheme to produce improved results. Since there are

    many parameters to be considered, it seems that a fair

    comparison with other super resolution algorithms

    cannot be made, resulting in no comparisons presented

    in this paper. Experiments with a number of sets of

     parameters suggest that our algorithm yields results

    which are quite comparable if not superior to some of

    the algorithms [17, 16] especially when the training set

    images are of very low resolution. 

    We have constructed a super-resolution algorithm that

    is based on training set [7], and introduced a faster,

    simpler, and, we believe, better super-resolution

    algorithm of single pass. The algorithm requires the

    training set of LR images from a still surveillance

    camera to produce HR image data and enhances it using

    anisotropic Diffusion and De-noising. In the image

     based representations, this technique of super resolution

     provides a great step towards resolution independenceThe application of this method was successfully

    demonstrated for the restoration from a short low

    resolution set of images into a super resolved image. 

    RECOMMENDATIONS

    The approach we described here possibly will be very

    useful in image processing techniques and graphics

    applications (see [6, 13]). A recent Home Office study

    found that 80 per cent of images from CCTV cameras

    were of such poor quality that they were worthless as

    evidence. For the enlargement of images, removal of

    noise, estimation of shapes of 3-D surfaces and forattacking the other imaging application, Training sets

    can be built and used. We assumed the gray images that

    were registered and were spatially static for our

    restoration of images in multi frame super resolution.

    Reviewing previous work on image re-sampling theory

    draw from the literature of computer, we formed a

    relationship between contrasting research areas. In our

    research, we demonstrated that Resampling theory of

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    images can be handy to imaging systems that are

    aligned. The supremacy of this approach is fabricated in

    the larger training sets, proper noise reduction models,

    allowing rendering models and rich prior probabilities

    and, allowing efficient scene inference. This algorithm

    of super resolution provided the state of the art results

    when applied. Furthermore, this work can be expanded

     by using colored images of low resolution as a data set

    hence producing comparable results.

    ACKNOWLEDGMENT 

    This paper is made possible through the help and

    support from everyone, including: parents, teachers, and

    friends. 

    The product of this research paper would not be

     possible without all of them.

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