A Preprocessing Framework for Underwater Image Denoising Essay Example for Free

A Preprocessing Framework for Underwater Image Denoising Essay Abstract A major obstacle to underwater operations using cameras comes from the light absorption and scattering by the marine environment, which limits the visibility distance up to a few meters in coastal waters. The preprocessing methods concentrate on contrast equalization to deal with nonuniform lighting caused by the back scattering. Some adaptive smoothing methods like anisotropic filtering as a lengthy computation time and the fact that diffusion constants must be manually tuned, wavelet filtering is faster and automatic. An adaptive smoothing method helps to address the remaining sources of noise and can significantly improve edge detection. In the proposed approach, wavelet filtering method is used in which the diffusion constant is tuned automatically. Keywords: underwater image, preprocessing, edge detection, wavelet filtering, denoising. I. INTRODUCTION The underwater images usually suffers from non-uniform lighting, low contrast, blur and diminished colors. A few problems pertaining to underwater images are light absorption and the inherent structure of the sea, and also the effects of colour in underwater images. Reflection of the light varies greatly depending on the structure of the sea. Another main concern is related to the water that bends the light either to make crinkle patterns or to diffuse it. Most importantly, the quality of the water controls and influences the filtering properties of the water such as sprinkle of the dust in water. The reflected amount of light  is partly polarised horizontally and partly enters the water vertically. Light attenuation limits the visibility distance at about twenty meters in clear water and five meters or less in turbid water. Forward scattering generally leads to blur of the image features, backscattering generally limits the contrast of the images. The amount of light is reduced wh en we go deeper, colors drop off depending on their wavelengths. The blue color travels across the longest in the water due to its shortest  wavelength. Current preprocessing methods typically only concentrate on local contrast equalization in order to deal with the nonuniform lighting caused by the back scattering. II. UNDERWATER DEGRADATION A major difficulty to process underwater images comes from light attenuation. Light attenuation limits the visibility distance, at about twenty meters in clear water and five meters or less in turbid water. The light attenuation process is caused by the absorption (which removes light energy) and scattering (which changes the direction of light path). Absorption and scattering effects are due to the water itself and to other components such as dissolved organic matter or small observable floating particles. Dealing with this difficulty, underwater imaging faces to many problems: first the rapid attenuation of light requires attaching a light source to the vehicle providing the necessary lighting. Unfortunately, artificial lights tend to illuminate the scene in a non uniform fashion producing a bright spot in the center of the image and poorly illuminated area surrounding. Then the distance between the camera and the scene usually induced prominent blue or green color (the wavelength corresponding to the red color disappears in only few meters). Then, the floating particles highly variable in kind and concentration, increase absorption and scattering effects: they blur image features (forward scattering), modify colors and produce bright artifacts known as â€Å"marine snow†. At last the non stability of the  underwater vehicle affects once again image  contrast. To test the accuracy of the preprocessing algorithms, three steps are followed. 1) First an original image is converted into grayscale image. 2)  Second salt and pepper noise added to the grayscale image. 3) Third wavelet filtering is applied to denoise the image. Grayscale images are distinct from one-bit bi-tonal black-and-white images, which in the context of computer imaging are images with only the two colors, black, and white. Grayscale images have many shades of gray in between. Grayscale images are also called monochromatic, denoting the presence of only one (mono) color (chrome). Grayscale images are often the result of measuring the intensity of light at each pixel in a single band of the electromagnetic spectrum and in such cases they are monochromatic proper when only a given frequency is captured. Salt and pepper noise is a form of noise typically seen on images. It represents itself as randomly occurring white and black  pixels. An image containing salt-and-pepper noise will have dark pixels in bright regions and bright pixels in dark regions. This type of noise can be caused by analog-to-digital converter errors, bit errors in transmission. Wavelet filtering gives very good results compared to other denoising methods because, unlike other methods, it does not assume that the coefficients are independent. III. A PREPROCESSING ALGORITHM The algorithm proposed corrects each underwater perturbations sequentially.  addressed in the algorithm. However, contrast equalization also corrects the effect of the exponential light attenuation with distance. B. Bilateral Filtering Bilateral filtering smooth the images while preserving edges by means of a nonlinear combination of nearby image values. The idea underlying bilateral filtering is to do in the range of an image what traditional filters do in its domain. Two pixels can close to one another, occupy nearby spatial location (i.e) have nearby values. Closeness refers to vicinity in the domain, similarity to vicinity in the range. Traditional filtering is a domain filtering, and enforces closeness by weighing pixel values with coefficients that fall off with distance. The range filtering, this averages image values with weights that decay with dissimilarity. Range filters are nonlinear because their weights depend on image intensity or color. Computationally, they are no more complex than standard nonseparable  filters. So the combination of both domain and range filtering is known as bilateral filtering. A. Contrast equalization Contrast stretching often called normalization is a simple image enhancement technique that attempts to improve the contrast in an image by ‘stretching’ the range of intensity values. Many well-known techniques are known to help correcting the lighting disparities in underwater images. As the contrast is non uniform, a global color histogram equalization of the image will not suffice and local methods must be considered. Among all the methods they reviewed, Garcia, Nicosevici and Cufi [2] constated the empirical best results of the illuminationreflectance model on underwater images. The low-pass version of the image is typically computed with a Gaussian filter having a large standard deviation. This method is theoretically relevant backscattering, which is responsible for most of the contrast disparities, is indeed a slowly varying spatial function. Backscattering is the predominant noise, hence it is sensible for it to be the first noise Anisotropic filtering Anisotropic filter is used to smoothing the image. Anisotropic filtering allows us to simplify image features to improve image segmentation. This filter smooths the image in homogeneous area but preserves edges and enhance them. It is used to smooth textures and reduce artifacts by deleting small edges amplified by homomorphic filtering. This filter removes or attenuates unwanted artifacts and  remaining noise. The anisotropic diffusion algorithm is used to reduce noise and prepare the segmentation step. It allows to smooth image in homogeneous areas but it preserves and even enhances the edges in the image. Here the algorithm follow which is proposed by Perona and Malik [5]. This algorithm is automatic so it uses constant parameters selected manually. The previous step of wavelet filtering is very important to obtain good results with anisotropic filtering. It is the association of wavelet filtering and anisotropic filtering which gives such results. Anisotropic algorithm is  usually used as long as result is not satisfactory. In our case few times only loop set to constant value, to preserve a short computation time. For this denoising filter choose a nearly symmetric orthogonal wavelet bases with a bivariate shrinkage exploiting interscale dependency. Wavelet filtering gives very good results compared to other denoising methods because, unlike other methods, it does not assume that the coefficients are independent. Indeed wavelet coefficients in natural image have significant dependencies. Moreover the computation time is very short. IV. EXPERIMENTAL SETUP AND EVALUATION To estimate the quality of reconstructed image, Mean Squared Error and Peak Signal to Noise Ratio are calculated for the original and the reconstructed images. Performance of different filters are tested by calculating the PSNR and MSE values. The size of the images taken is 256256 pixels. The Mean Square Error (MSE) and the Peak Signal to Noise Ratio (PSNR) are the two error metrics used to compare image compression quality. The MSE represents the cumulative squared error between the compressed and the original image, whereas PSNR represents a measure of the peak error. The lower the value of MSE, the lower the error. In Table 1, the original and reconstructed images are shown. In table 2, PSNR and MSE values are calculated for all underwater images. PSNR value obtained for denoised images is higher, when compare with salt and pepper noise added images. MSE value obtained for the denoised images has lower the error when compared with salt and pepper noise added images. e D. Wavelet filtering Thresholding is a simple non-linear technique, which operates on one wavelet coefficient at a time. In its most basic form, each coefficient is thresholded by comparing against threshold, if the coefficient is smaller than threshold, set to zero; otherwise it is kept or modified. Replacing the small noisy coefficients by zero and inverse wavelet transform on the result may lead to reconstruction with the essential signal characteristics and with the less noise. A simple denoising algorithm that uses the wavelet transform consist of the following three steps, (1) calculate the wavelet  transform of the noisy image (2) Modify the noisy detail wavelet coefficients according to some rule (3) compute the inverse transform using the modified coefficients. Multiresolution decompositions have shown significant advantages in image denoising. best denoised image. In clearly, the comparisons of PSNR and MSE values are shown in Fig -1a and Fig -1b. V. CONCLUSION In this paper a novel underwater preprocessing algorithm is present. This algorithm is automatic, requires no  parameter adjustment and no a priori knowledge of the acquisition conditions. This is because functions evaluate their parameters or use pre-adjusted defaults values. This algorithm is fast. Many adjustments can still be done to improve the whole pre-processing algorithms. Inverse filtering gives good results but generally requires a priori knowledge on the environment. Filtering used in this paper needs no parameters adjustment so it can be used systematically on underwater images before every pre-processing algorithms. REFERENCES [1] Arnold-Bos, J. P. Malkasse and Gilles Kervern,(2005) â€Å"Towards a model-free denoising of underwater optical image,† IEEE OCEANS 05 EUROPE,Vol.1, pp.234256. [2] Caefer, Charlene E.; Silverman, Jerry. Mooney,JonathanM,(2000) â€Å"Optimisation of point target tracking filters†. IEEE Trans. Aerosp. Electron. Syst., pages 15-25. [3] R. Garcia, T. Nicosevici, and X. Cufi. (2002) â€Å"On the way to solve lighting problems in underwater imaging†. In Proceedings of the IEEE Oceans 2002, pages 1018–1024. [4] James C. Church, Yixin Chen, and Stephen V., (2008) â€Å"A Spatial Median Filter for Noise Removal in Digital Images†, page(s):618 – 623. [45 Jenny Rajan and M.R Kaimal., (2006) â€Å"Image Denoising Using Wavelet Embedded anisotropic Diffusion†, Appeared in the Proceedings of IEEE International Conference on Visual Information Engineering, page(s): 589 – 593. [6] Z. Liu, Y. Yu, K. Zhang, and H. Huang.,(2001) â€Å"Underwater image transmission and blurred image restoration†. SPIE Journal of Optical Engineering, 40(6):1125–1131. [7] P. Perona and J.Malik, (1990) â€Å"Scale space and edge detection using anisotropic diffusion,† IEEE Trans on Pattern Analysis and Machine Intelligence, pp.629-639. [8] Schechner, Y and Karpel, N., (2004) â€Å"Clear Underwater Vision†. Proceedings of the IEEE CVPR, Vol. 1, pp. 536-543. [9] Stephane Bazeille, Isabelle, Luc jaulin and Jean-Phillipe Malkasse, (2006) â€Å"Automatic Underwater image PreProcessing†, cmm’06 characterisation du milieu marine page(s): 16-19. [10] Yongjian Yu and Scott T. Acton, (2002) Speckle Reducing Anisotropic Diffusion, IEEE Transactions on Image Processing, page(s): 1260-1270, No. 11, Vol.11.

Hitlers Rise To Power :: essays research papers

How Hitler got into Power At the end of the war Germany underwent a rapid political restructuring. Following this transition from authoritarian monarchy to democratic republic, Weimar Germany immediately began to display weaknesses that it would ultimately never fix. Germany had to create a government that the Allies would be prepared to negotiate with, so Hindenburg ordered a government which had the support of the Reichstag. When Kaiser William II fled the country, Germany could still have remained a monarchy, as William's son was eligible for the throne. The Weimar Republic was not based on strong public convictions, which must, in part, explain its weakness. There were many flaws in thew Weimar Republic. Weimar had great problems gaining acceptance throughout Germany, too. The terribly harsh conditions of the Treaty of Versailles angered Germans, especially the military everywhere and many directed their resentment at the Weimar government who signed the Treaty. Defeat in a large-scale war always signals the beginning of a difficult period for a nation. Following World War I, Germany was virtually crushed by the harsh demands of the Treaty of Versailles. The German economy was weighed down heavily by the enormous reparations bill. Weimar governments struggled to meet the huge reparations payments and their failure to do so was the basis of further problems. One such event was the additional humiliation of the French and Belgian occupation of the Ruhr in 1923. The French took control of the coal mines and factories of the region, so the workers, following a policy of passive resistance, went on strike. The French employed their own men to work the area, whilst the German government committed to paying the wages of the striking workers. This was a very expensive exercise and, on top of that, Germany lost profits from industry in the Ruhr and actually had to spend money importing coal. These massive drains on the German economy caused inflation to soar to incredible levels, paralleling the dramatic drops in the value of the reichsmark. It is true that the Reichsbank printed more and more money to the point where over 44 trillion marks was in circulation. Some historians argue that the Weimar government did this deliberately, to devalue their currency, making it cheaper to pay reparations. The downside of this was that middle and working class Germans lost their savings and the value of their wages. For instance in November 1923, the cost of a loaf of bread in Berlin was about 201 billion marks!

What legal rights (if any) does Milesofpaper Ltd have in respect of payment for the stationery and office equipment??

Introduction As Mr Frank and Mr Stamp entered into the contract with Milesofpaper Ltd before the incorporation of Wearboaters Ltd, it would appear that the contract was entered into under the partnership of Pleasure Boats & Co and thereby governed by the Partnership Act (PA) 1890. In order for a partnership to be created, there must be two or more persons that conduct business with a view to profit. Partnerships are defined under s. 1(1) PA 1890 as a â€Å"relation subsisting between persons carrying on business in common with a view of profit†. Mr Frank and Mr Stamp had clearly entered into a partnership as they carried on business (pleasure boat building and repairing) with a view to profit; Khan v Miah, Ahad and Miah[1]. Unlike companies, partnerships do not have a separate corporate personality and are instead regarded as a collection of individuals or persons.[2] This means that each partner is jointly liable, without limit, for the debts and obligations of the partnership incurred wh ile he or she is a partner (s. 9 PA 1890). Mr Frank and Mr Stamp will therefore both be personally liable for any debts the partnership incurred; M Young Legal Associates Ltd v Zahid[3]. In considering whether Milesofpaper has any rights in respect of payment for the stationary and office equipment, it will need to be considered whether Mr Frank and Mr Stamp are personally liable the contact is capable of binding the partnership. Given that both partners entered into the contract with Milesofpaper, they will be deemed to have had actual authority to bind the firm. S. 5 PA 1890 states that every partner is an agent of the firm whose acts bind the firm and his partners, unless the partner acting had no authority to do so. Given that both Mr Frank and Mr Stamp would have the authority to enter into the contract with Milesofpaper, it is clear that their actions would have bound the firm. However, because the contract was entered into under the company’s name; Wearboaters Ltd, it is doubtful that this particular transaction will be binding against the partners. It is noted under s. 6 PA 1890 that an act relating to the business of the firm must be done in the firm name or any other manner to be binding on the firm and all its partners. Since the act relating to the business of the firm was done in the name of the new unincorporated company, it is unlikely that the partnership will be liable for the debt. Ye t, the individual who entered into the contract may be liable for the debt as their own private act[4]; Sangster v Biddulph[5]. Furthermore, even though Wearboaters Ltd has now been incorporated, Milesofpaper Ltd will not be able to enforce the pre-incorporated contract. The reason for this is that; â€Å"before incorporation, the company is not competent to enter into contract in its own name as it has no legal entity†[6]. As such, Wearboaters Ltd will not be capable of being sued for the pre-incorporation contract that was entered into between Mr Frank, Mr Stamp and Milesofpaper. In Re English & Colonial Product Co[7] it was held that a company was not liable to pay for services and expenses incurred by a solicitor pre-incorporation as the company was not in existence at the time when the expenses were incurred. In addition, it was also held in CIT v City Mills Distilleries (P) Ltd[8] that a company has no status prior to its incorporation and can have no income or liability. As the company had not been incorporated, Mr Frank and Mr Stamp will be classed as ‘promoters’ who will have purported to enter into a contract by or on behalf of Wearboaters Ltd[9]. As promoters, Mr Frank and Mr Stamp will be personally liable unless the contract states otherwise (s. 51 Companies Act (CA) 2006). In Phonogram Ltd v Lane[10] it was held that a promoter of a company was personally liable to repay a deb t that was made on the company’s behalf under s. 51 CA 2006 (previously 2. 36 CA 1985) even though the claimant was unaware that the company was not in existence at the time the contract was entered into. Overall, it is likely that Milesofpaper will have a claim against Mr Frank and Mr Stamp in respect of payment for the stationery and office equipment. What legal rights (if any) do Mr Frank and Mr Stamp have in respect to payment for compensation for the destroyed boats and equipment? Once a company has been incorporated, it is separate and distinct from its members as shown in Salomon v Salomon[11]. Here, it was made clear that a company shall be solely liable for any losses or mishaps that arise within the company. In accordance with this principle, a company has the capacity to enter into contracts and sue and be sued in its own name. If the company suffers a breach of contract, it is the company who will be able to sue on the contract for breach and thereby seek to take the appropriate remedial action[12]. As business assets are owned by the company, it is the company who is responsible for insuring them. Because Mr Frank had insured the assets of the business under the partnership, the assets that have been transferred to the company will no longer be insured. This is because Mr Frank does not have an insurable interest in the company’s assets and a new contract would need to have been entered into between the company and the insurer. This was identifi ed in Macaura v Northern Assurance Co Ltd[13] where Macaura was the owner of a timber estate who took out an insurance policy in his own name. Most of the timber was destroyed by fire but Macaura could not claim for loss of goods as he did not have an insurable interest in the timber. It was held that a person cannot claim for loss of goods that are owned by another party. As the company owned the timber, Macaura could not make a claim. Since Wearboaters Ltd is the new owner of the assets, Mr Frank will not be able to make a claim as they no longer have an insurable interest in the assets. When the assets were transferred a new insurance policy should have been taken out in Wearboaters Ltd’s name. As Mr Frank and Mr Stamp have failed to take out a new insurance policy, they will be deemed to have breached their directors’ duties and will be found personally liable for the loss that has been caused to the business. It cannot be said that Mr Frank and Mr Stamp were promoting the success of the company as required under s. 172 CA 2006 and will therefore be liable for any losses incurred; Re Duomatic[14]. This is an exception to the rule in Salomon that a company is separate and distinct from its members and thus allows the corporate veil to be lifted in certain circumstances. In addition, Mr Frank and Mr Stamp also breached their duty to â€Å"exercise reasonable care, skill and diligence† under s. 174 CA 2006 as shown in Secretary of State for Trade and Industry v Goldberg[15]. Although the courts are generally reluctant to lift the corporate veil, they will do so when â€Å"common sense and reality demand it†[16] and when â€Å"there is a powerful argument of principle for lifting the corporate veil where the facts require it†[17]. It could be said that this is to apply in the instant situation as Mr Frank and Mr Stamp should have insured the assets of the business as they were the first directors of Wearboaters Ltd. The courts will only pierce the corporate veil in very limited circumstances, however, and if Mr Frank and Mr Stamp can demonstrate that there was no evidence of â€Å"fraud, illegality or a sham or if the company is a mere facade concealing the true facts† (ss. 213-215 of the Insolvency Act 1986, s. 993 CA 2006 and s. 15 of the Company Directors Disqualification Act 1986), then it is unlikely that they will be found personally liable; Adams v Cape Industries plc[18]. As noted by Talbot; â€Å"veil piecing is not an end in itself but a means to an end†[19]. Therefore, unless the circumstances of the case give rise to fraud or a pre-existing obligation, the courts will be unlikely to pierce the veil in its entirety; Pirelli Cable Holding NV v IRC[20]. It has been said that the courts will â€Å"go to great lengths to avoid any obvious penetration of the corporate veil, whilst still making the sort of inquiries that would be satisfied by just such a process†[21]. T his prevents the doctrine from being completely undermined, whilst also protecting the public; Millam v Print Factory (London) 1991 Ltd[22]. The veil will only be lifted in exceptional circumstances[23] so as to prevent individuals from being discouraged from investing in companies[24]. Overall, given that it Mr Frank and Mr Stamp appear to have made a genuine mistake in respect of the insurance, it is unlikely that they will be found personally liable. However, they will not be entitled to compensation for any loss suffered. Bibliography Text Books A Dignam and J Lowry. Company Law (Core Text Series). (Oxford: OUP Oxford, 2012). D French. S Mason. and C Ryan. Mason, French & Ryan on Company Law, (Oxford: Oxford University Press, 2013). L Jones. Introduction to Business Law. (Oxford: OUP Oxford, 2013). L Talbot, L. Critical Company Law, (London: Routledge, 2007). P P S Gonga. A Text Book of Company Law., (London: Chand, 2002). Journal Articles S Ghaiwal, S. ‘Chandler v Cape plc: Is there a chink in the corporate veil?’ (2012) Health and Safety at Work Newsletter, vol 18, no 3, 487-499. V V Watcher. ‘The Corporate Veil’ (2007) New Law Journal, vol. 990, no. 7218, 22-27. Legislation Partnership Act 1890 Cases Adams v Cape Industries plc [1990] Ch 433 CIT v City Mills Distilleries (P) Ltd (1996) 2 SCC 375 Khan v Miah, Ahad and Miah [2001] All ER Macaura v Northern Assurance Co Ltd [1925] AC 619 Millam v Print Factory (London) 1991 Ltd [2007] EWCA Civ 322 M Young Legal Associates Ltd v Zahid [2006] EWCA Civ 613 Pirelli Cable Holding NV v IRC [2006] UKHL 4 Phonogram Ltd v Lane (1982) QB 938 Re Duomatic [1969] 2 Ch 365 Re English & Colonial Product Co (1906) 2 Ch 435 Salomon v Salomon [1987] AC 22 Sangster v Biddulph [2005] PNLR 33 Secretary of State for Trade and Industry v Goldberg [2004] 1 BCLC 557

Department Of Media And Communication - 2242 Words

DEPARTMENT OF MEDIA COMMUNICATION MA (Fashion Journalism) A RESEARCH PROPOSAL BY: Full names: ROHAIZATUL AZHAR B AB RAHIM Student no: ABR 14439179 Postal address: 23B ARCHEL ROAD, W14 9QJ Telephone number: +44 747 826 0640 E-mail: r.abrahim1@arts.ac.uk Date of submission: January 30, 2015 This submissions contains two (02) parts: Unveiling the Hijabista: When Faith meets Fashion Evaluation of ‘The Roles of Media in Influencing Women Wearing Hijab: An Analysis’ by Zulkifli Abd. Latiff and Fatin Nur Sofia Zainol Alam Part 1: Unveiling The Hijabista - When Faith Meets Fashion 0.0 Introduction The Merriam-Webster dictionary (2015) defines hijab as the ‘traditional covering for the hair and neck that is worn by Muslim†¦show more content†¦Assisted by the socio-technological developments caused by new (mobile) communication technologies (Blommaert and Varis 2015), these influencers have started a sartorial movement that brings together two seemingly opposing ideas in order to create an indigenous identity. Known as Hijabista, a term coined by Jerome Taylor in The Independent newspaper (2010), they are defined as â€Å"a trendy set of up-and-coming Muslim women† (Taylor 2010) who dresses fashionably while still conforming to the code as prescribed by Islam through the donning of hijab. Being a Hijabista can therefore be seen as a sartorial technology of the self (Foucault 1988) through recognisable emblematic values of fabrics, cuts, accessories and styles (Blommaert and Varis 2015). The emergence of the Hijabista stems from the modern Muslim women’s desire to assimilate into western civilisation and to show that they too are in on the game. The word Hijabista is a hybridisation of ‘Hijab’ and ’fashionista’; the latter being taken to mean ‘one who is a keen follower of trends and style’. Because the relationship between Islam and women’s fashion is a conflicting one, the global perception of the Hijab is one that is associated with oppression and failure to adapt to progress and modernity. However, in recent years, those in Muslim-majority nations have began showing how the hijab is in fact a symbol of freedom. This rise in the hijab-wearing community of Middle-Eastern countries, such as Kuwait and