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A Novel Technique for Modification of Images for Deuteranopic Viewers

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ISSN (Online) 2278-1021 IJARCCE ISSN (Print) 2319 5940 International Journal of Advanced Research in Computer and Communication Engineering Vol. 5, Issue 4, April 2016 A Novel Technique for Modification of Images for Deuteranopic Viewers Jyoti D. Badlani1, Prof. C.N. Deshmukh 2 PG Student [Dig Electronics], Dept. of Electronics & Comm. Engineering, PRMIT&R, Badnera, Amravati, Maharashtra, India1 Professor, Dept. of Electronics & Comm. Engineering, PRMIT&R, Badnera, Amravati, Maharashtra, India2 Abstract: About 8% of men and 0.5% women in world are affected by the Colour Vision Deficiency. As per the statistics, there are nearly 200 million colour blind people in the world. Color vision deficient people are liable to missing some information that is taken by color. People with complete color blindness can only view things in white, gray and black. Insufficiency of color acuity creates many problems for the color blind people, from daily actions to education. Color vision deficiency, is a condition in which the affected individual cannot differentiate between colors as well as individuals without CVD. Colour vision deficiency, predominantly caused by hereditary reasons, while, in some rare cases, is believed to be acquired by neurological injuries. A colour vision deficient will miss out certain critical information present in the image or video. But with the aid of Image processing, many methods have been developed that can modify the image and thus making it suitable for viewing by the person suffering from CVD. Color adaptation tools modify the colors used in an image to improve the discrimination of colors for individuals with CVD. This paper enlightens some previous research studies in this field and follows the advancement that has occurred over the time. It also approaches different methods of modifying and adjusting images so that the persons suffering from dichromacy are able to better perceive image detail and color dynamics. This paper includes three algorithms; they are LMS daltonization, color contrast enhancement, and LAB color adjustment. Two separate technique are also used for evaluation of the effectiveness of these techniques. First; the simulation of deuteranopia is done on both the original and processed images to observe the algorithm‟s effects from the perspective of a color blind viewer. Second; delta E image is obtained between the two images in order to assess the extent to which the image changes from the perspective of a non-color blind viewer and also, the Elapsed time is calculated for the algorithms. A brief comparison is also done between Color contrast enhancement, LAB color adjustment and LMS daltonization. Keywords: Deuteranopia, Dichromacy, CVD, LMS Daltonization, RGB Color Constrasting, LAB Color Correction, Elapsed time. I. INTRODUCTION Human normal color vision requires three kinds of retinal The following figure helps to understand how the color photoreceptors. These are called L, M, and S cone cells, image appears to a color blind viewer depending on the and have higher sensitivity to the long, medium, and short type of color blindness. wavelengths of the visible spectrum, respectively. The specific type of photopigment contained in each kind of cone cell determines its spectral response. Some natural variations in the composition of these photopigments can shift their spectral sensitivities to different bands of the visible spectrum [1]. In this case, the affected individuals are called anomalous trichromats, and can be further classified as protanomalous, deuteranomalous, or tritanomalous, if the affected photopigment is associated with the L, M, or S cones, respectively. The bigger the shift, the more the individual‟s color perception will vary with respect to the Fig1.Image perception of a Color-blind person perception of an individual with normal color vision (normal trichromat). The person can be classified as As a consequence of the existence of three types of protanope, deuteranope, or tritanope, according to the type photoreceptors, normal color vision spans a 3-D color of the missing photopigment (L,M, or S, respectively). space. The color gamut of a dichromat, on the other hand, Much rarer conditions include the cases of individuals is only two-dimensional and can be represented by a with a single kind of photopigment (cone monochromats) surface patch in the same 3-D color space. Such a reduced or no functional cone cells at all (rod monochromats). gamut is the cause of the ambiguity experienced by Copyright to IJARCCE DOI 10.17148/IJARCCE.2016.54118 467 ISSN (Online) 2278-1021 IJARCCE ISSN (Print) 2319 5940 International Journal of Advanced Research in Computer and Communication Engineering Vol. 5, Issue 4, April 2016 dichromats: many different colors are perceived as the Depending upon which cone is not aligned properly it is same, when projected onto such patches. For anomalous further divided into: trichromats, the color gamut falls in between these two extremes, moving towards the gamut of a dichromat as the 1) Protanomaly: In Protanomaly the sensitivity to red degree of severity of the anomaly increases. For spectral colour is reduced. shifts of approximately 20 nm, the perception of an 2) Dueteranomaly: In Dueteranomaly, the sensitivity to anomalous trichromat becomes similar to the perception of green colour is reduced. a dichromat [1, 2]. 3) Tritanomaly: In Tritanomaly, the sensitivity to blue As stated by William Woods [3], Color blindness affects colour is reduced. roughly ten percent of human males. It is possible for a woman to be color blind, but the because a defect in the X TABLE I MAJOR GENETIC COLOR DEFICIENCIES[4] chromosome leads to main type of color blindness, so most color blind individuals are men. About ninety-nine Name Cause Prevelance percent of them suffer from some sort of red-green Dichromacies deficiency, where a person is unable to differentiate Protanopia Missing L males:1.0% properly between red and green. A non color blind person cone females: 0.02% can perceive three wavelength groups. Dichromacy is a Deuteranopia Missing M males:1.1% general term for a person‟s lack of ability to perceive one cone females: 0.1% of these three wavelengths. There are three types of Tritanopia Missing S cone Very rare receptor cones in the normal human eye that are often Anomalous referred to as red, green, and blue (RGB); technically they Trichromacies are receptors of long, medium, and short (LMS) Protanomaly Abnormal L males:1.0% wavelengths respectively. Three types of complete cone females: 0.02% dichromacy exist. Protanopia is an absence of red cones, Deuteranomaly Abnormal M males:4.9% deuteranopia is an absence of green cones, and tritanopia cone females: 0.04% is an absence of blue cones. II. LITERATURE REVIEW Types of color blindness: Inspite of the relevance of understanding how individuals A. Monochromacy -If there is no cone or only one type of with CVD perceive colors, there has been little work done cone present at retina of eye then it is called in simulating their perception for normal dichromats. Over Monochromacy. In Monochromacy, person is unable to years, there have been many techniques but none of the see any color. All things seem to be black, white and gray. previous approaches is capable of handling dichromacy in the way that this paper does. B. Dichromacy- If there are only two types of cones present at retina of eye then it is called Dichromacy. In Based on the report on unilateral dichromat individual by Dichromacy, any one type of cones is missing. So [5], achromatic colors as well as some other hues are information about that particular wavelength is lost. perceived similarly by both eyes (approximately Dichromacy is again of three types according to the wavelengths of 475 nm and 575 nm by individuals with missing cone:- protanopia and deuteranopia, and 485 nm and 660 nm by tritanopes). This formed a basis for development of many 1) Protanopia: If the type of missing cones is L-cone then techniques for image adjustment and modification as it it is called Protanopia. Due to protanopia, long provided effective insight to the perception of images as wavelength color information is lost, so the person observed by person with CVD. suffering from protanopia is unable to see red color. This is called „Red blindness‟. In the work done by [6], this gamut has been mapped in 2) Deuteranopia: If the type of missing cones is M-cone the XYZ color space. They also mapped confusion lines in then it is called Deuteranopia. Due to deuteranopia, this color space, which represent directions along which medium wavelength color information is lost, so the there is no color variation according to dichromats person suffering from deuteranopia is unable to see perception. By projecting colors through confusion lines green color. This is called „Green blindness‟. into the reduced gamut, they have defined an accurate 3) Tritanopia: If the type of missing cones is S-cone then technique for simulating dichromacy. it is called Tritanopia .Due to tritanopia, short wavelength color information is lost, so the person Latter, some other similar works have been developed suffering from tritanopia is unable to see blue color. by[7]. Amongst others, the technique proposed by [7] is This is called „Blue blindness‟. the most referenced of all existing simulation techniques. In this technique, the color gamut of dichromats is mapped C. Anomalous Trichromacy-In this condition all the types to two semi-planes in the LMS color space, while the of cones are present but they are not aligned properly. authors constrained the direction of confusion lines to be Hence, the sensitivity to a particular colour is reduced. parallel to the direction of the color space axes L, M, or S, Copyright to IJARCCE DOI 10.17148/IJARCCE.2016.54118 468 ISSN (Online) 2278-1021 IJARCCE ISSN (Print) 2319 5940 International Journal of Advanced Research in Computer and Communication Engineering Vol.
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