Investigation on Color Composite Images of TM Data. (II)

Effects of Band Combination and Color Sequence on Visual Interpretation

Abstract

The purpose of this report is to examine effects of band combination and color sequence on visual interpretation and to select some suitable combinations and sequences. TM data used is WRS 111-36 (Setouchi) scene received at NASDA EOC on May 8, 1984. Color composites used are 210 kinds of 240 × 240mm (1 : 1, 000, 000) images which are made of three primary colors and three bands from TM seven bands in the previous report. Aptitude for visual interpretation of the images is investigated as follows. Because of relatively low definition of the thermal band (band 6), interpretation is made on the color composites excluding and including band 6 separately. On the former, aptitude for interpretation is examined on eight kinds of large scale objects and on twelve kinds of small scale objects separately. On the latter, the aptitude is examined on eight kinds of large scale objects and four kinds of relatively large scale objects, i. e. twelve kinds of objects. At the first step, the aptitude for the each object is examined with a method of five grades including the first grade always on one group of 20 kinds of images excluding band 6 and another group of 15 kinds including band 6 in one block of 35 kinds to each color sequence separately. Then the mean of scores of each band combination to 6 kinds of all color sequences for the each object is calculated and the best band combinations are selected. At the second step, the best scored images are picked up and aptitude for the each object is examined on them elaborately. The each of them is ranked in order of aptitude for the each object. On the basis of these results, the best band combination and color sequence is selected. Finally frequency of each color sequence in the best images is counted from the results of the second step and the best for the all objects is selected.
In case of band combinations excluding band 6, the best is (257) to the large scale objects or (345) to the small scale objects. In case of band combinations including band 6, good combinations are (376) and (356). The best color sequence is (BGR) or (BRG) in all of the cases.