Effect of image resolution on intensity based scene illumination classification using neural network

Figures & data

1 Step by step flow chart of implemented system

2 Sample of input images with their corresponding SIV value

3 Sample of image histograms (256 × 256) with their corresponding quarter's value. Vertical lines separating quarters from each other and horizontal line refer to ideal histogram level. Horizontal axis represents CIE XYZ y component value; vertical axis represents number of pixels in each Y component value

4 Designed neural network structure: eight inputs correspond to eight features (mean, mode, median, SIV and Q1 to Q4), and three outputs correspond to three output clusters (low, ideal and high illumination)

5 Misclassification rate analysis. On left, chart shows misclassification rate changes by changing image resolution. On right, separated improvement of each image resolution is compared to others by percentages. Negative values in table show that instead of reduction increase occurred

6 Mean square error analysis. On left, chart shows MSE changes by changing image resolution. On right, separated improvement of each image resolution is compared to others by percentages in terms of MSE

7 R square analysis. On left, chart shows R square changes by changing image resolution. On right, separated improvement of each image resolution is compared to others by percentages in terms of R square

Table 1 Feature values for three different images from various illumination classes presented by various image resolutions

Sample	Resolution	Avg	Mode	Median	Q1	Q2	Q3	Q4	CV
Low	64	54	22	53	2727	1208	132	29	1.0608
	128	54	23	52	10986	4637	601	160	1.0605
	256	54	21	51	43,858	18,334	2,503	831	1.054
	512	54	23	50	174,465	74,096	9,506	4,077	1.047
	1024	54	23	50	694,001	299,930	36,403	18,242	1.041
	2048	54	15	49	2,768,017	1,206,272	141,736	78,279	1.038
Ideal	64	109	34	104	1021	1460	1381	234	0.473
	128	109	47	103	5633	5314	1197	2660	0.427
	256	109	157	101	17,489	22,080	20,464	5503	0.397
	512	109	160	100	71,570	86,389	80,112	23,893	0.375
	1024	109	86	100	292,092	341,148	315,081	100,255	0.362
	2048	109	163	99	1,178,477	1,356,504	124,932	409891	0.356
High	64	158	248	167	640	466	1561	1429	0.1587
	128	159	248	170	2707	1691	5844	57600	0.1472
	256	159	238	171	11156	6308	24022	24050	0.1447
	512	159	255	173	46043	24512	93283	98306	0.1410
	1024	159	255	175	188512	100383	353208	406473	0.1393
	2048	159	255	175	188512	100383	353208	406473	0.1399

8 Coefficient of variation of histogram quarter features separated by image illumination class: (A) low illumination class, (B) ideal illumination class and (C) high illumination class