公开(公告)号：US5172227A

公开(公告)日：1992-12-15

申请号：US625232

申请日：1990-12-10

申请人： Yushing T. Tsai ,  Scott J. Daly ,  Majid Rabbani

发明人： Yushing T. Tsai ,  Scott J. Daly ,  Majid Rabbani

IPC分类号： H04N9/68 ,  H04N1/58 ,  H04N1/64 ,  H04N7/26 ,  H04N7/30 ,  H04N9/04 ,  H04N9/07 ,  H04N11/04

CPC分类号： H04N11/042 ,  H04N1/58 ,  H04N1/64 ,  H04N9/045 ,  H04N19/30

摘要： In accordance with the present invention, the R,G,B color image signals from a single sensor having a color filter array are all transformed to .GAMMA.-space by changing them to R.sup.1/.GAMMA., G.sup.1/.GAMMA., B.sup.1/.GAMMA., respectively, where .GAMMA. is approximately 2.4. In this space, all operations such as color differencing, interpolation of those missing pixels required for color differencing, compression, decompression, edge enhancement and final interpolation of all missing pixels are performed without further transformation of the image signals. For the same final bit rate, noise in the reproduced image is reduced by refraining from interpolating the missing color pixels prior to compression of the image data. In order to avoid over-emphasizing features of the image which are already sufficiently sharp, the combined outputs of horizontal and vertical sharpening processes are subjected to a paring process of the invention which suppresses strong high-spatial frequency components as a function of their amplitude. In the compression-decompression process of the invention, each spatial frequency coefficient of the spatial frequency-transformed image is divided by a normalization factor determined by cascading in the spatial frequency domain the human visual system contrast sensitivity function, the edge enhancement modulation transfer function and the image display modulation transfer function and inversing the resulting matrix elements.

摘要翻译： 根据本发明，来自具有滤色器阵列的单个传感器的R，G，B彩色图像信号都分别通过将它们改变为R1 / GAMMA，G1 / GAMMA，B1 / GAMMA而被转换为GAMMA-空间， GAMMA约为2.4。 在这个空间中，无需进一步转换图像信号，就可以执行所有的操作，例如色差，色差分离，压缩，解压缩，边缘增强和最终内插丢失像素的插值。 对于相同的最终比特率，通过在压缩图像数据之前不进行内插丢失的颜色像素来减少再现图像中的噪声。 为了避免已经足够锐利的图像的过度强调特征，水平和垂直锐化处理的组合输出经受本发明的配对过程，其抑制强大的高空间频率分量作为其幅度的函数。 在本发明的压缩解压缩过程中，空间频率变换图像的每个空间频率系数除以由空间频域中的级联确定的归一化因子，人类视觉系统对比度敏感函数，边缘增强调制传递函数和 图像显示调制传递函数和反转所得到的矩阵元素。