Abstract
I read with interest the paper of McLean et al. about the use of camera phones for telehaematology. 1 In the discussion, the authors described the study as having assessed the specifications required for transmission and for receipt of appropriate images. However, only one mobile phone was used for acquiring images from a single microscope, the images then being sent to 33 mobile phones for examination. Acquisition thus depended on just one sample subject, from which it is difficult to generalise. However, the paper provided no specification regarding the requirements of the sender camera phone (e.g. resolution, objective features, software), although the magnification to be used was discussed.
McLean et al. report, perhaps unsurprisingly, that a dedicated microscope camera produced much better images than those of the camera phone. I wish to suggest some additional reasons for this, in addition to camera calibration and white balance setting. First of all, a dedicated camera does not add optics to the optical path of the microscope; the camera phone has an objective in front of the acquisition chip, with its own characteristics, including the fact that it is often made of plastic, rather than optical-quality glass. Among the objective features, one that will limit image quality is optical resolution, which will probably be lower than microscope resolution. Another reason is due to the acquisition device: the Nikon DN100 used by McLean et al. has a small CCD sensor, while the Sony Ericsson k810i has a relatively cheap CMOS sensor, which is likely to produce images with more electronic ‘noise’. In addition, the phone embedded software automatically applies noise reduction algorithms to the image, which may result in loss of detail. 2 Finally, the method of focusing through the eyepiece may produce slightly out-of-focus images, because when viewing a 3.2 Mpixel image on a 320×240 pixel screen (i.e. a 76 kpixel display) the smallest detail that can be seen is 42 times greater (in area) than the smallest detail acquired, although phone autofocus helps in better focusing beyond screen limits.
Nonetheless, the paper provides an assessment of the receipt of appropriate images, based on tests with a fair number of camera phones. Regarding this, I assume that the images in Table 3 were acquired from the dedicated microscope camera, because in my own attempts to acquire images with a Sony Ericsson k800i I found that the resultant images had a circular shape (like the eyepiece), with a dark border. It would be interesting to see a direct comparison between those acquired with a phone camera and those seen on phones.
I have a concern about the possible use of these results. The paper attempts to measure two distinct aspects of the use of camera phones: (1) as an acquisition and transmission device and (2) as a possible viewing station, independently from the camera eventually present on the phone. Regarding the former aspect, the paper demonstrates that a camera phone is sub-standard, so its use should be considered only in emergency situations where no other appropriate camera is available. Regarding the latter aspect, the only reason I see for using camera phones as viewing stations is the need for mobility of the recipient haematologist; if not, it is much better to receive images on a proper viewing station. If costs are a concern, netbook computers now cost much the same as some mobile phones and provide a much better viewing device.
According to the authors, using a camera phone may be a way of overcoming the limitations in remote transmission produced by the network firewalls used to maintain the integrity of a hospital IT environment. Firewalls and other security measures can in fact be configured to allow outbound communications. 3 The functioning of a firewall is governed by the relevant security policy, which is first a matter of what the hospital management considers feasible, and usually this depends on current laws related to security and privacy. So, while acceptable for research purposes, attempting to circumnavigate the technical filter provided by a firewall implies an attempt to circumnavigate a security rule with legal consequences. If image transmission is deemed necessary for clinical work, then the right step is to negotiate with legal and IT specialists in the hospital about the correct approach, although I understand that, when novel fields and techniques are envisaged, it may be difficult to communicate the need to IT personnel who are generally trained only to deal with standard, traditional applications.