Spectral Test Instrument for Color Vision Measurement

Common displays such as CRT or LCD screens have limited capabilities in displaying most color spectra correctly. The main disadvantage of these devices is that they work with three primaries and the colors displayed are the mixture of these three colours. Consequently these devices can be confusing in testing human color identification, because the spectral distribution of the colors displayed is the combined spectrum of the three primaries. We have developed a new instrument for spectrally correct color vision measurement. This instrument uses light emitting diodes (LEDs) and is capable of producing all spectra of perceivable colors, thus with appropriate test methods this instrument can be a reliable and useful tool in test~ing human color vision and in verifying color vision correction.

Prevalence of color vision deficiency among Chinese college students and their quality of life

AIM:To investigate the prevalence of color vision deficiency(CVD)among college students and their quality of life(QoL)in a Chinese college.METHODS:This cross-sectional study was performed in Sichuan University in Chengdu,China.The questionnaire containing participants’demographic data,as well as CVD related QoL was distributed to students who were screened as CVD[by Color Vision Examination Plates(Version 6)]in 2022 freshman entrance examination.Color blindness QoL(CBQoL)and utility analysis were used to evaluate the QoL of CVD students.RESULTS:There were 381 of 17303(2.20%)students screened as CVD,including 368(4.11%)males and 13(0.16%)females.A total of 317 students completed the questionnaire,the response rate was 83.20%.Only 166 participants(52.3%)knew they have CVD before the physical examination for college entrance examination,while a total of 145 participants(45.74%)hoped to be diagnosed earlier.The medians of CBQoL score and utility were 5.85(range 2.2-6)and 1(range 0-1),respectively.The proportions of students whose QoL is affected by CVD were 67.63%(211/312)and 42.27%(134/317)measured by CBQoL and utility analysis respectively.CONCLUSION:The prevalence of CVD in males is much higher than that in females.The time when CVD students first became aware of their CVD is relatively late.The QoL of the study population is quite high,while a large proportion of students’QoL are affected by CVD.It is suggested that as a congenital defect,CVD screening in China should be earlier,and appropriate guidance and support are needed for CVD patients to help them better adapt to life,study,and work.

The prevalence of red-green color vision deficiency and its related factors in an elderly population above 60 years of age

AIM:To determine the prevalence of red-green(RG)color vision deficiency(CVD)in an elderly population and its related factors.METHODS:This report is a part of the Tehran Geriatric Eye Study:a cross-sectional population-based study that was conducted on the elderly population(≥60y)of Tehran,Iran using multi-stage stratified random cluster sampling.All study participants underwent complete ocular examination,including the measurement of uncorrected and bestcorrected visual acuity,objective and subjective refraction,and slit-lamp biomicroscopy.The color vision was tested using Ishihara plates with the near optical correction in place.RESULTS:Of the 3791 invitees,3310 participated in the study.The data of 2164 individuals were analyzed after applying the exclusion criteria.The prevalence of R-G CVD was 3.73%(95%CI:2.37%–5.09%)in the whole sample;the prevalence of protanomaly,protanopia,and deuteranopia was 1.51%,1.76%,and 0.45%,respectively.The prevalence of R-G CVD was significantly higher in males than in females.The prevalence of RG CVD increased with advancing age from 2.91%in the age group 60–64y to 5.8%in the age group≥80y(P=0.070).According to the multiple logistic regression model,male sex,and glaucoma were significantly related to RG CVD.Older age and hypertension also had a marginally significant relationship with RG CVD.CONCLUSION:Changes in color vision occur in the elderly due to the aging process and some physiological and pathological factors.Since the change in visual perception may affect the person’s performance,this aspect of the visual system’s function should also be taken into consideration in the examinations of the elderly.

Effects of chronic smoking on color vision in young subjects

AIM: To evaluate the effects of chronic smoking on color vision in young subjects.METHODS: This study included 91 smokers and 88non-smokers(a total of 179 volunteers) without any ophthalmologic and systemical disorders. The subjects were between 18-40 years of age with a best corrected visual acuity(BCVA) of 20/20, normal anterior and posterior segment examinations and normal intraocular pressure. The color vision of the subjects were evaluated with Farnsworth-Munsell 100 Hue test(FMHT). The total error scores and axis calculation were performed for each subject and the results correlated.RESULTS: Mean age and the standard deviation was28±5y in the smokers group, and 26.7±5.5y in the control group(P =0.101). Sex distribution was similar in the two groups(P =0.365). There was no significant correlation between age and FMHT total error scores(P =0.069).Median of FMHT total error scores of smokers and non-smokers were 65 and 50.50, respectively. FMHT total error scores was found significantly higher in smokers than non-smokers(P =0.004). There was no statisticaly significant difference between smoker and non-smoker groups with respect to axis ratio calculation(P =0.611).There was no significant correlation with FMHT total error scores with neither smoking duration nor number of cigarettes smoked per day(P =0.405, P =0.454,respectively).· CONCLUSION: This study suggested that chronic smoking affects the color vision of young smokers but this may not be sector selective.

Detection of Gene Alteration for Color Vision Defects by Polymerase Chain Reaction

According to the fact that the abnormalities of visual pigment genes were always involved in the changing of the exon 5, two oligonucleotide primers were designed to amplify the exon 5 of red pigment gene and green pigment gene. After electrophoresis of the PCR products digested with Rsal or Sau3A, the DNA fragments from the exon 5 of red pigment gene (RPG) and green pigment gene (GPG) were separated since there are different restriction endonuclease sites. On the other hand, we analyzed the exon 5 rela...

A Study of Spectral Electroretinogram of Color Vision Defects Due to Macular Diseases

Studies of spectral electroretinograms in central serous retinopa-thy (CSR) and hereditary macular degeneration (HMD) showed that the b-wave amplitudes of most wavelengths of CSR were significantly decreased as compared with normal controls, and those of HMD were obviously lower than the normal values. Patients of HMD with type-A color vision defects (CVD) had primarily a reduction of b-wave amplitudes in the full spectrum of 480-620 nm, and patients with type- I CVD a reduction of b-wave amplitudes wav...

The Normal Color Vision Evaluated With FM 100-hue Test

One hundred and twenty normal subjects (240 eyes) agedfrom 10 to 69 were tested with FM 100-hue test.They were divided into6 groups according to their age.It was shown that there were no statisti-cally significant difference in the total error score (TES) between the malesand females or between the right and left eyes,but there existed some rela-tionships between the TES and age.The total error score (TES) was thelowest in the 20-29 age group and increased gradually with aging.Theanalysis of the partial...

Color Vision Defects with Variation in the Exon 5 of Red and Green Pigment Genes

Purpose : To investigate correlation of variation in the exon 5 of red and green pigment genes with color vision defects.Methods : Exon 5 of the red and green pigment genes in 11 protans, 19 deutans and 38 normal controls were analyzed by heteroduplux-SSCP analysis.Results : In all 11 protans and 8 of the 19 deutans, defects of the red or green pigment gene could be identified. The C polymorphism (A/C at codon 283) in green pigment gene was present in 8 of 44 trichromats and 5 of 24 dichromats. Specific electrophoretic bands were found in 2 normal controls and a deutan.Conclusions: Variation in the exon 5 of the red and green pigment genes is the most common cause for color vision defects. Heteroduplex-SSCP analysis is a suitable way in screening specific variation in visual pigment genes. Eye Science 1998; 14 : 130 - 133.

The Objective Measure of Color Vision in Primary Open Angle Glaucoma

Purpose: To objectively evaluate the clinical application of color pattern reversal visual e-voked potential (CPR-VEP) on primary open angle glaucoma (POAG). Methods: CPR-VEP and FM 100-hue test were performed in 31 eyes with POAG and 33 normal eyes. Color pattern stimulation was presented by color monitor controlled by computer program. The reversal rate of the stimulating pattern was 2 Hz and the spatial frequency of the stimulating was 0.53 cycle/degree. The color stimulating pattern include White /Black , Red/Black , Green/Black , Blue/Black , Yellow /Black , Red/Green and Blue /Yellow . Results : CPR-VEP P1 latencies were obviously prolonged in POAG group in comparison with normal control group in equiluminance. All CPR-VEP P1 amplitudes, except Blue/Black P1 amplitude, show no differences between POAG group and normal control group . Conclusion: P1 latencies of all CPR-VEP and P1 amplitude of Blue/Black CPR-VEP were parameters for identifing acquired dyschromatopsia caused by POAG. The results

Prevalence and gene frequency of color vision impairments among children of six populations from North Indian region

X-linked redegreen color blindness is the most widespread form of vision impairment.The study aimed to determine the prevalence and gene frequencies of redegreen color vision impairments among children of six different human populations of Jammu province.A total of 1028 healthy subjects(6e15 years of age)were selected from five Muslim populations and the color vision impairments were determined using the Ishihara’s test of color deficiency.The gene frequency was calculated using HardyeWeinberg equilibrium method.The prevalence of color vision deficiency(CVD)ranged from 5.26%to 11.36%among males and 0.00%e3.03%among females of six different populations.The gender based differences in the frequency of CVD was found to be statistically significant(p<0.0001),with a higher prevalence among male(7.52%)as compared to female(0.83%)children.We observed high frequency of deutan as compared to protan defects.The incidences of deuteranomaly(5.68%)and deuteranopia(2.27%)were higher among male children of Syed population while the frequencies of protanomaly(1.94%),protanopia(1.28%)and achromacy(2.27%)were the highest among male subjects of Khan,Malik and Syed populations,respectively.The allele and genotype frequencies showed cogent differences among six populations.The population based assessment of CVDs help patients to follow adaptive strategies that could minimize the risks of the disease.

An objective method for color vision deficiencies measurement based on visual evoked potential

The equi-luminance of color stimulus in normal subjects is characterized by L-cone and M-cone activation in retina. For the protanopes and deuternopes, only the activations of one relevant remaining cone type should be considered. The equi-luminance turning curve was established for the recorded visual evoked potentials (VEPs) of the luminance changes of the red and green color stimulus, and the position of the equi-luminance was used to define the kind and degree of color vision deficiencies. In the test of 47 volunteers we got the VEP traces and the equi-luminance turning curves, which was in accordance with the judgment by the pseudoisochromatic plate used in clinic. The method fulfills the objective and quantitative requirements in color vision deficiencies test.

Developing a Machine Vision System Equipped with UV Light to Predict Fish Freshness Based on Fish-Surface Color

This study assessed the feasibility of developing a machine vision system equipped with ultraviolet (UV) light, using changes in fish-surface color to predict aerobic plate count (APC, a standard freshness indicator) during storage. The APC values were tested and images of the fish surface were taken when fish were stored at room temperature. Then, images’ color-space conversion among RGB, HSV, and L*a*b* color spaces was carried out and analyzed. The results revealed that a* and b* values from the UV-light image decreased linearly during storage. A further regression analysis of these two parameters with APC value demonstrated a good exponential relationship between the a* value and the APC value (R2 = 0.97), followed by the b* (R2 = 0.85). Therefore, our results suggest that the change in color of the fish surface under UV light can be used to assess fish freshness during storage.

Continuous Pseudocolor Encoding of Thermal Image Display

The visual features of continuous pseudocolor encoding is discussed and the optimiz- ing design algorithm of continuous pseudocolor scale is derived.The algorithm is restricting the varying range and direction of lightness,hue and saturation according to correlation and naturalness,automatically calculating the chromaticity coordinates of nodes in uniform color space to get the longest length of scale path,then interpolating points between nodes in equal color differences to obtain continuous pseudocolor scale with visual uniformity.When it was applied to the pseudocolor encoding of thermal image displays,the results showed that the correlation and the naturalness of original images and cognitive characteristics of target pattern were reserved well;the dynamic range of visual perception and the amount of visual information increased obviously;the contrast sensitivity of target identification improved;and the blindness of scale design were avoided.

COLOR CHANNEL AND FIGURE CHANNEL AND PERCEPTION TO COLOR IN VISUAL SYSTEM

Some new exporinients with the aid of computer are designed to studythe relationship between color channel and fisure channel in human visual system.The results prove that the two channels are parallel and independent from each other.A hypothesis model of the unity principle of the two channel is put forward.

Effect of glaucoma on identification of bottle cap color in ophthalmic medications

A prospective, nonrandomized, observational trial of 60 glaucoma patients to correlate visual acuity and visual field with ability to distinguish bottle cap color of commonly used ophthalmic medications was conducted. A total of 103 eyes from 60 patients(30 women) were evaluated. The mean logMAR acuity was 0.34±0.54(approximately 20/45 Snellen acuity), average Humphrey Visual Field(HVF) mean deviation was-8.58±8.69 dB, mean Ishihara plates(out of 14) were 11.78±4.15, and bottle cap color score(out of 10) was 8.56±2.51. Multiple linear regression analysis revealed an independent correlation of visual acuity(P=0.0137) and Ishihara score(P<0.001) with cap color score, but no significant effect with visual field mean deviation(P>0.05). Glaucoma patients with poor visual acuity, but not necessarily advanced visual field loss, are likely to have difficultly identifying the color of their bottle caps. Physicians should be cognizant of this potential issue when reviewing medications with patients.

Color Estimation for Thermal Infrared Imagery Based on Kernel PCA and Sparse Representation

Adding colors to monochrome thermal infrared images can help observers understand the scenery better. A nonlinear color estimation method for single-band thermal infrared imagery based on kernel principal component analysis (KPCA) and sparse representation was proposed. Nonlinear features of infrared image were extracted using KPCA. The relationship between image features and chromatic values was learned using sparse representation and a color estimation model was obtained. The thermal infrared images can be rendered automatically using the color estimation model. The experimental results show that the proposed method can render infrared image with an accurate color appearance. The proposed idea can also be used in other color estimation problem.

Study of Vision Problems in Schools in Libreville and Owendo, Gabon

The purpose of this work is to evaluate the epidemiological aspects of vision problems and their repercussions in the schooling of children in Libreville and Owendo. Methodology: This transversal and descriptive study was carried out in May and June 2011. Included in the study were children in the 7th and 8th grades of the primary schools in Libreville and Owendo. For each child, an eye exam, including the subjective measure of visual acuity, was carried out using the Monoyer scale, and the color vision assessment was carried out with the Ishihara test. Any visual capacity under or equal to 7/10th in at least one eye was considered to be pathological. We gathered information about demographic characteristics, any preceding vision issues on the record, data on other medical problems on the record and the eye examination on computer cards. Results: Nine hundred and sixty-three children (416 boys and 517 girls, with a gender ratio of 0.86) were examined. The average age was 12 ± 1.7 years old. The prevalence of the drop in visual acuity was 16.2%. The prevalence of color vision anomalies was 15.5%. Complaints concerning vision problems were significantly more present from children with a drop in visual acuity (p 0.01). Visual anomalies had an impact on the children’s schoolwork, and yet, visits to the ophthalmologist’s office were few. Conclusion: The frequency of anomalies in vision justifies systematic screening in schools and organization of an appropriate treatment.

Color Reproduction on CRT Displays via BP Neural Networks Under Office Environment

A CRT characterization method based on color appearance matching is presented. A matching between Munsell color chips and CRT charts was obtained in vision perceiver in typical office environment and viewing condition by recommending. And neural networks were utilized to accomplish the color space conversion from CIE standard color space to CRT device color space. The neural networks related the color space conversion and color reproduction of soft/hard-copy directly to the influence of the illuminance and viewing condition in vision perceiver. The average color difference of training samples is 3.06 and that of testing samples is 5.17. The experiment results indicated that the neural networks can satisfy the requirements for the color appearance of hard-copy reproduction in CRT.

基于VisionPro的颜色识别分类系统研究

通过VisionPro视觉软件,搭建高效率、高识别率的颜色识别分类的机器视觉系统。设计四轴机器人控制系统,对相机进行手眼标定,通过视觉处理引导机械手完成颜色识别与分类。为验证系统的有效性,以3种颜色块进行试验,在随机摆放的情况下,对颜色块进行识别与分类。实验结果中识别率达到98.3%以上,且算法具有良好的鲁棒性,可以实现自动识别分类工作。

Automatic Quality Inspection of Bakery Products Based on Shape and Color Information

An automatic intelligent system for the colour and texture inspection of bakery products is proposed.In this system,advance classification technique featuring Support Vector Machine and biologically inspired HMAX based shape descriptor integrated with biologically plausible RGB Opponent-Colour-Channel Descriptor is used to classify bakery products to their respective classes based on the shape and based on their colour referring to different baking durations. The results of this paper are compared with other methods for the automatic bakery products inspection. It is discovered that biologically inspired computer vision models performs accurately and efficiently as compared to the computer vision models which are not biologically plausible,in the bakery products quality inspection. It is also discovered that the One Versus One SVM and Directed Acyclic Graph SVM acquired the maximum accurate classification rate. The proposed method acquired classification accuracy of 95% and 100% for the biscuit shape and biscuit colour recognition,respectively. The proposed method is also consistently stable and invariant. This shows that the biologically inspired computer vision models have the capability to replace existing inspection methods as more reliable and accurate alternative.