Image Quality Evaluation of HJ CCD Sensors

The Chinese HJ saterllite CCD sensor is similar to Landsat-5 TM with the same spatial resolution, but there are enormous advantages in space coverage and frequency of repeated observations. This paper focuses on the image quality evaluation of the four HJ CCD sensors by reference to Landsat TM data from near-synchronous images. The results are as follows: Mainly due to limited evel of radiation acceptance per unit area, there's a sharp quality gap between HJ-1A CCD data and TM data in radiometric resolution and image sharpness. This leads to decrease of image recognition ability, such as image interpretation, feature extraction, image measurement etc. No obvious difference has been found in image information entropy and power spectrum summation. This will guarantee the classification accuracy. We also conclude that standard false colour composition of band 4, 3, 2 is the best band combination choice. There's no significant difference between the four CCD sensors. Among the four bands, red and near-infrared shows the best quality while the blue shows the worst. The NDVI from HJ CCD data can achieve the similar accuracy of NDVI from TM data.