Techniques are proposed in which, using a microscope for observing samples such as cell tissue slides, images of the samples observed through the microscope are saved as digital images, and the saved digital images are observed by other devices provided over the Internet or an intranet (see, for example, Japanese Unexamined Patent Application Publication No. 2003-222801). The use of such techniques is able to promote the development of so-called telepathology in which doctors at remote places perform pathology diagnoses using networks.
Consequently, in a microscope that generates digital images of samples such as cell tissues, the samples are magnified using a magnification optical system and magnified images are projected into an image sensor to capture digital images. At this time, because the depth of field of the microscope is extremely narrow at about 1 μm or so, there is a necessary for multiple captured image data in which the focus position is deviated in the depth direction of the sample, in order to capture an image of the entire sample having a thickness. In addition, even when the sample is relatively small in thickness, there may be a case where the locally optimal in-focus positions are different from each other in one magnified image due to undulation or the irregularities of the cell tissue, and there may be a case where multiple captured image data are necessary in which the focus positions are deviated in the depth direction.
In addition, observers of the digital images operate an input unit such as a mouse in a terminal for observing the digital images, and observe data of digital images captured in advance. At this time, the operators observe the digital images of the targeted sample while changing the positions of observation in a three-dimensional manner such as right to left, up and down and in the depth direction as though the operators were viewing the slide through the microscope by operating the input unit. Here, when the multiple captured sample images are observed in the depth direction, the operators operate a mouse wheel and the like, and can perform focus adjustment by themselves.
However, as mentioned above, because the thickness or undulation exists in the sample to be observed, the operators of the terminal for observing the digital images have to perform focus adjustment each time they change sites of observation. However, there is a problem in that such focus adjustment puts the observers to much trouble.