1. Field of the Invention
The present invention relates to a wireless image transmission system having a portable small-sized camera (hereinafter, referred to as xe2x80x98portable cameraxe2x80x99) for taking pictures in secret at a predetermined place, and more particularly to a wireless image transmission system having a portable camera for monitoring situations at a remote location by mounting a sensor or the like in a case which can not be recognized by others.
2. Description of the Prior Art
There is a situation in which a camera is; necessarily used without its exposure to others for various purposes. For example, a portable camera is sued by a policeman to photograph an illegal trade spot or for monitoring facilities or the like disposed at a specific location. In general, a small-sized camera is installed in a bag or the like, a signal is transmitted through a wire or in a wireless manner, and then a desired object is monitored or recorded at a remote location through the portable camera. Such portable cameras are getting smaller due to technology development. However, since a wireless transmission device or a recording device is needed for transmitting a signal to a remote location or for recording an image, there is a limitation in reducing the size of a portable camera. Further, even though cameras are becoming much smaller, it is difficult to made a camera small-sized to an extend that others can not recognize it.
Accordingly, it is an object of the present invention to provide a wireless image transmission system having a portable camera in a shape which can not be readily recognized by others.
In order to attain the above object, the portable camera includes a case having a ball-point pen appearance in a portion thereof and a through hole in one side; and a camera circuit part mounted in the case and for photographing an object through the through hole.
As a ball-point pen is carried in a pocket of a shirt in general, people do not pay particular attention to the ball-point pen held in the pocket. In the mean time, since the ball-point pen has adequate room therein for mounting a printed circuit board including an image sensor for taking pictures, a shape of a ball-point pen may be a most proper appearance of a portable small-sized camera.
In general, a ball-point pen has a button and a clip on an upper portion thereof and a protruded nib on a lower portion. In order to reduce weight of a portable camera of a ball-point pen shape, it is preferable to use only an upper portion of the ball-point pen. That is, as only an upper portion of a ball-point pen is held on a pocket of a shirt by a clip for use, the weight due to a refill or any parts on a lower portion can be reduced.
In case that a user carries a portable camera with him, it is preferable to form a through hole of the portable camera at a position enabling a user to take pictures frontwards. It is preferable to form the through hole on the clip concretely, on the connection portion of the clip and the body of a ball-point pen more concretely. In case that a microphone is provided to the portable camera under the necessity of catching an audio signal, it is preferable to mount the microphone on an upper portion, that is, on a portion for a button of a ball-point pen. In order to enhance voice transmission to the microphone, it is preferable to form a through hole on a portion on which the microphone is mounted.
A lens may be mounted in the through hole or on an image sensor in order for light to be projected to the image sensor from outside. Preferably, the lens is mounted for an image to be exactly projected on the image sensor. If necessary, a lens driver may be provided for an exact lens focus.
Preferably, the camera circuit part includes an image sensor and a control circuit for processing a signal of the image sensor. Any device, as an image sensor, for taking pictures may be used, but it is preferable to use a small sensor manufactured in a semiconductor process. The image sensor for black and white colors is preferable for simplifying its component specification. It is preferable for the control circuit to process both an audio signal of the microphone and a signal of the image sensor.
Further, in order to attain the above object, the wireless image transmission system for transmitting an image to a remote location includes a portable camera having a ball-point pen appearance in a portion thereof and a camera circuit part mounted therein for taking pictures; a transmission device for transmitting a signal from the portable camera to a remote location; and a receiving device for receiving a signal transmitted from the transmission device.
Even though a ball-point pen has enough space therein for mounting circuit components, the space is not so spacious enough to accommodate a recording device for recording images taken by the camera or the transmission device. Accordingly, such devices, which has a relatively complex structure with a large volume, are preferably provided as independent devices from the portable camera.
For example, the portable camera is connected to the wireless transmission device by electric wires, and then an image signal and an audio signal are transmitted to a wireless receiving device at a remote location through the wireless transmission device. It is preferable that the portable camera and the wireless transmission device are carried somewhere in the body of a user and the wireless receiving device is separately mounted at a remote location. The valid transmission distance of a signal from the wireless transmission device is different according to a frequency in use, a conversion method, and an environment in use. Accordingly, in certain circumstances, the wireless receiving device, which is small-sized, is connected to the recording device and then may be put in a portable bag, or the wireless transmission device is constructed to amplify and transmit a signal from the wireless transmission device to a more remote location. Any method known in this field may be employed as a wireless transmission method of the wireless transmission device, but it is preferable to perform the transmission through the RF modulation. If a RF modulation method is employed, it is more preferable to use a frequency band free from any interference with other RF signal. It is preferable that the wireless transmission device has a size and weight to an extent that a user can bear it on the belt around his waist.
Power supply for operating the wireless transmission device and the portable camera is preferably provided to the wireless transmission device, but if necessary, the power supply may be provided separately from the wireless transmission device or the portable camera. In case that power supply is mounted to the wireless transmission device, it is preferable that the power supply is provided to the portable camera through a cable which connects the portable camera with the wireless transmission device.