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          麦克维斯基教授批驳母国光院士的“国际首创”“黑白胶片照彩照”

                             ·方舟子·

    《光学学报》1997年第8期发表言放文章《黑白胶片光栅编码彩色摄影术》，
指出1991年中国十大科技新闻之一“南开大学母国光等首创黑白胶片作彩色摄影
技术”，“实际是抄袭(甚至在某一方面倒退)的产物。只要将这个专利和Macovski
的专利中的任何一个放在一起对比就能得出这个结论。”

    母国光等人以“白光信息处理课题组”的名义在《光学学报》1998年第5期发
表了反驳文章《用三色光栅和黑白感光胶片作彩色摄影术的研究与进展》，认为
言放窜改了Macovski的意思，声称“Macovski和Mueller的三色光栅,都只是提出
一种构想和结构示意图,并没有实际给出制造三色光栅和彩色编码相机的设计,更
没有制造彩色图像解码仪的设计。而本文作者经过多年的反复设计和实验,成功
地制造出三种型号的三色光栅编码器。在研制过程中解决了许多技术上的问题。”
“不能把示意与设计混为一谈。Macovski在他专利中,建议了图3中的Fig.3和Fig.4
的三补色光栅,但是实际上从没有见到这两种三色光栅的任何实物和有关实验报道。
事情是清楚的。”“其次,人们从图3[8](Macovski专利中的Fig.6、Fig.7、Fig.8
和Fig.9)很清楚地看到,Macovski专利所提出的编码方式,是多次曝光的编码,而不
是一次编码。”

    当时已有人向麦克维斯基教授（Albert Macovski，美国斯坦福大学教授）询
问对此事的看法，麦氏在两封电子邮件中对母国光院士的说法一一进行了批驳。
在征得麦氏教授的同意后，我们在这里公布这两封信件。麦氏教授在信件中指出，
他们早在多年以前（六、七十年代）就已用多种技术制造出了三色光栅的相机和
摄像机，其中这类摄像机曾由RCA和Matsushita公司大量制造和销售，而不是如母
文所说的仅仅是一种构想、没有制造设计和实物。麦氏的编码方式是一次曝光编
码，而不是如母文所说的“多次曝光的编码”。麦氏指出，他们当时也完成了大
尺寸、高分辨率的航空摄影用的光学图像处理系统，而母国光等人在1993年才开
始承担“大幅面航空光学信息处理处理设备”项目，1997年年底通过鉴定。麦氏
不明白母国光等人为何不用三补色光栅，却改用三原色光栅，认为这会显著地降
低光效率和质量。

    从麦氏教授所言可知，母国光院士等人研制的“黑白胶片光栅编码彩色摄影
术”不是国际首创，而是国外在70年代初期起就已淘汰的旧技术，而且母院士采
用的技术不仅不是突破，而是一种倒退。

附：麦克维斯基教授两封电子邮件原文

Date: Wed, 4 Feb  1998 16:34:44  -0700 (PST)

Thank you for your letter of January 7. I will try to recall our work 
on encoded color, although it was a long time ago.

In answer your questions:

1. Indeed we made many tricolor gratings in our lab using many 
different techniques.

2. The size of the grating depended on the application. For vidicon 
cameras it was the size of the target. In many of our systems we used 
relay optics which enabled the use of a very large grating.

3. Using subtractive primaries each grating encodes one color and 
enables the other two to pass without absorption. If you use the 
additive primaries you get complete crosstalk amongst the colors and 
significantly reduced light efficiency. Additive colors can only be 
used in a sequential encoding process as described by Bocca.

4. Video cameras using color encoding gratings have been manufactured 
and sold by RCA and Matsushita. They were made in great numbers prior 
to the use of CCD cameras. I don't know if encoded photographic camera 
were ever manufactured.

5. I don't know whether Professor Mueller could have used a tricolor 
grating.

6. I believe you are referring to the work sponsored by the NASA space 
agency where we studied high-resolution color encoding. These were 
gratings of high density. I don't know of any important progress after 
the early seventies except for the work of Matsushita on low-cost 
color cameras.

Thank you for your inquiry.

Sincerely,

Albert Macovski


Date: Tue, 21 Jul 1998 11:57:49 -0700 (PDT)


Thank you for your letter and emails. Unfortunately I am too busy to
participate in this controversy.
There is no question that the tri-color grating was implemented and
installed in a camera for single exposures. That was always our
program and it was completely carried out both in photographic cameras
and in video cameras. The video cameras were produced commercially by
many companies.

I am also confused about the use of the additive primaries, red,green,
and blue as compared to the absorptive primaries, yellow, magenta, 
and cyan.  I cannot see why anyone would use red, green, and blue in a
single exposure grating filter. Only the absorbtive primaries, yellow,
magenta, and cyan provide the desired action. A grating of alternate
lines of yellow and transparent material will represent a grating for
blue light and pass the other two colors, red and green,
undisturbed. Similar for the cyan and magenta stripes. This is not
true with red, green and blue. They will interfere with each other and
be highly inefficient.

I wish you success in your endeavors and I am sorry that I am unable
to participate.

Sincerely,

Albert Macovski
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