EDTV-II has reported to the MPT by the Telecommunications Technology Council (TCC), in January, 1995. EDTV-II transmits the main panel signal and the upper and lower blank panel signal. The upper and lower blank panel signal may annoy viewers watching conventional televisions. So, several techniques have been employed to reduce this interference in EDTV-II. We describe "the adaptive gain control technique" that is one of the interference reducing techniques. This technique extracts the correlation between the main panel signal and vertical-temporal signal, and controls the gain of the upper and lower blank panel signal. In this paper, the effects of this technique through a computer simulation and subjective assessments are described.
The format of EDTV-II has reported to the MPT by the TCC in January, 1995. We have developed experimental EDTV-II encoder based on this format. In this report, we discribe the feature of this encoder in detail, about the pre-filter and the interface to progressive scanning lines convertor which do not use motion adaptive processing.
This paper describes experimental hardware of EDTV-II Encoder/Decoder based on tentative standards. In this scheme, VT (Vertical-Temporal helper) signal and VH (Vertical High helper) signal are transmitted in upper and lower panels, and HH (Horizontal High helper) signal is embedded on the "Hole" in the main panel. Several methods are used for reducing the upper and lower panel interference to current receivers. This hardware was used for verification test of tentative standards.
The results of the horizontal and vertical resolution were very close to the set target. We obtained the results that were in accordance with the guideline through the experiment to discriminate the signalling signal. The only exceptional observation was that in some instance, the existing video signal was mistaken for the signalling signal. With respect to the degradation of the group delay and frequency characteristic on the transmission, the degradation of the picture quality of EDTV-II was geater than NTSC.
The Broadcasting Technology Association (BTA) has carried out a series of evaluation tests with the aim of establishing a standard for EDTV-II. Among the tests conducted, this paper will report on the results of subjective evaluation tests of picture quality, susceptibility to noise or interference, and compatibility. In the picture quality test, we confirmed an average improvement of about half a grade in test materials including a still picture and four moving sequences when rating on a seven-grade comparison scale using, as a reference, the current NTSC with an aspect ratio of 4 : 3. However, we observed, the EDTV-II tends to be slightly more susceptible to random noise and interferences than NTSC.
The authors analyze co-channel interference one EDTV-II in the three-dimensional frequency domain, based on the laboratory tests held by BTA (Broadcasting Technology Association). They verify the analyzed results by computer simulation, with comparing the degradation on NTSC and EDTV-II receivers. As a result, the simulation results proved that the analysis is correct, and it was clarified that the EDTV-II seems more degraded than the NTSC because of vertical 3-4 conversion as well as helper signals processing.
In this paper, we propose the usage of "Bit 17" in the EDTV-II signalling code, which is assigned for indication of "still picture and film mode". It is pointed out that not only the performance of pro-scan conversion but also the SNR of the VT (vertical-temporal) helper signal can be improve at the receiver in this mode. We also propose a sophisticated signalling method which identifies 24fps film mode, 30fps film mode, and still picture mode by indicating whether the current field has been generated from the same film frame as the previous field.