Image signal recording device

An image signal recording device comprises a remaining amount detecting processor which detects a remaining amount of a memory card, which is recordable. When the remaining amount is greater than a recording capacity, which is necessary for recording an image signal corresponding to a single image, the image signal is recorded in the memory card. When the remaining amount is less than the recording capacity, an image area, which is included in the image and can be recorded in the memory card, is indicated on a surface of a display device. A compression ratio is inputted, if necessary, so that a compressed image signal, corresponding to the image area, is recorded in the memory card.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to an image signal recording device by which 
an image signal corresponding to a single image is recorded in a recording 
medium. 
2. Description of the Related Art 
Conventionally, there is known an image signal recording device, in which a 
remaining amount of a recording medium is determined prior to a recording 
operation of an image signal in the recording medium. In this image signal 
recording device, the recording operation is prohibited when the remaining 
amount of storage area on the recording medium is less than the recording 
capacity necessary to record the whole of the image signal corresponding 
to a single image. 
Therefore, a problem concerning the image signal recording device arises, 
in which a recording area of the recording medium is useless, and thus the 
usage efficiency of the recording medium is insufficient. 
SUMMARY OF THE INVENTION 
Therefore, an object of the invention is to provide an image signal 
recording device by which an image signal can be recorded in a recording 
medium, even when a recordable area of the recording medium becomes small, 
so that the usage efficiency of the recording medium is improved. 
According to the present invention, there is provided an image signal 
recording device comprising a remaining amount detecting processor, 
detecting a remaining amount of a recording medium, which is recordable, 
and a recording processor. 
The recording processor can record at least a part of a single image in the 
recording medium, when the remaining amount is less than a recording 
capacity, which is necessary to record an image signal corresponding to 
the single image. 
Further, according to the present invention, there is provided an image 
signal recording device comprising a remaining amount detecting processor, 
a compression ratio setting processor and a recording processor. 
The remaining amount detecting processor detects a remaining amount of a 
recording medium, which is recordable. The compression ratio setting 
processor sets a compression ratio of an image signal, which is to be 
recorded in the recording medium. The recording processor can record a 
part of each of (N+.alpha.) number of images, N and .alpha. being positive 
integers, in the recording medium, when the remaining amount is less than 
a recording capacity necessary to record image signals, which correspond 
to N number of images and are compressed in accordance with the 
compression ratio.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
The present invention will be described below with reference to embodiments 
shown in the drawings. 
FIG. 1 shows a block diagram of an image signal recording device of an 
embodiment of the present invention. The image signal recording device is 
provided in an electronic still camera. 
The image signal recording device is controlled by a system control circuit 
10, provided with a microcomputer. An imaging device (charge-coupled 
device (CCD)) 11, which is a solid-state imaging device, is disposed on an 
optical axis of a photographing optical system (not shown), so that an 
image obtained through the optical system is formed on a light receiving 
surface of the CCD 11. The CCD 11 is controlled by the system control 
circuit 10, so that an image signal corresponding to the image is 
outputted from the CCD 11. The image signal is subjected to a 
predetermined process, such as a correlated double sampling (CDS), in an 
analog signal process circuit 12, and is then converted from an analog 
signal to a digital signal by an A/D converter 13. 
The digital image signal is temporarily stored in a buffer memory 15, 
through a digital signal process circuit 14. The digital image signal is 
read from the buffer memory 15, and inputted to the digital signal process 
circuit 14, in which the digital image signal is subjected to a 
predetermined process. The image signal, outputted from the digital signal 
process circuit 14, is converted into an image signal having a 
predetermined format in a memory card control circuit 16, and is recorded 
in a memory card 17. Note that an image compression operation, by which 
the image signal is compressed, is performed in the digital signal process 
circuit 14. 
The image signal outputted from the digital signal process circuit 14 is 
transmitted to an image indicating device 18, provided with a liquid 
crystal display, for example, so that an image is indicated on the surface 
of the image indicating device 18. Further, the image signal, outputted 
from the digital signal process circuit 14, is converted by an interface 
circuit 19 to a signal which conforms to a standard of an external device 
connected to an output terminal 20, and is outputted to the external 
device through the output terminal 20. 
An operation unit 21 and a display unit 22 are connected to the system 
control circuit 10. The operation unit 21 is provided with a selection 
switch for selecting a compression ratio of an image and an image area of 
the image, which are to be used when recording the image in the memory 
card 17. The display unit 22 is provided with a liquid crystal display for 
indicating a data, which, for example, implies an operation mode of the 
image signal recording device. 
When the remaining amount of the memory-card 17, which is recordable, is 
insufficient to record an entire image signal, an image area of the image, 
an image signal of which can be recorded in the memory card 17, is 
indicated on the surface of the image indicating device 18. In the digital 
signal processing circuit 14, the image signal corresponding to the image 
area is extracted under control of the system control circuit 10, and thus 
the image signal is recorded in the memory card 17. 
FIG. 2 is a first example of a flowchart of a program, by which an image 
signal is recorded in the memory card 17. This program is started when a 
record switch provided in the operation unit 21 is operated to set a 
record mode. 
In Step 201, the remaining amount "F" of the memory card 17, which is 
recordable, is detected. In Step 202, the initial value of the compression 
ratio "R" is set to 1, which implies "non-compression". In Step 203, it is 
determined whether a compressed-image recording capacity "V/R", which is 
obtained by dividing the original recording capacity "V", necessary for 
recording an image signal corresponding to a single image, with the 
compression ratio "R", is greater than the remaining amount "F" of the 
memory card 17. When the compressed-image recording capacity "V/R" is less 
than or equal to the remaining amount "F", Step 211 is executed, in which 
the image signal is recorded in the memory card 17, using the compression 
ratio "R". Conversely, when the compressed-image recording capacity "V/R" 
is greater than the remaining amount "F", Step 204 and the following Steps 
are executed, enabling the image signal to be increasingly compressed and 
recorded in the memory card 17. Thus, this program ends. 
In Step 204, a frame indicating an area of the image, which can be recorded 
in the remaining amount "F" of the memory card 17, is indicated at the 
center portion of the surface of the image indicating device 18. FIG. 5 
shows such a frame 27, which has the same aspect ratio as the original 
image. When the remaining amount "F" changes, the size of the frame 
correspondingly changes. In Step 205, it is determined whether the 
compression ratio "R" is to be changed. The alternation of the compression 
ratio "R" is performed by operating the selection switch provided in the 
operation unit 21. When the value of the compression ratio "R" is changed, 
the new compression ratio "R" is set in Step 206, and then the process 
returns to Step 203. 
In Step 203, it is determined whether the compressed-image recording 
capacity "V/R", obtained by dividing the original recording capacity "V" 
using the compression ratio "R" set in Step 206, is greater than the 
remaining amount "F". When the compressed-image recording capacity "V/R" 
is less than or equal to the remaining amount "F", Step 211 is executed, 
in which the image signal is recorded in the memory card 17, using the 
compression ratio "R" set in Step 206. Conversely, when the 
compressed-image recording capacity "V/R" is greater than the remaining 
amount "F", Steps 204 through 206 are again executed. 
While the loop composed of Steps 203 through 206 is executed, if it is 
determined in Step 205 that the compression ratio "R" should not be 
changed, based on the operation of the selection switch of the operation 
unit 21, Step 208 is executed, in which it is determined whether the 
position of the image area is to be selected. The image area is indicated 
on the surface of the image indicating device 18, by the execution of Step 
204, and is the maximum area, corresponding to the maximum amount of the 
image signal, which can be recorded in the memory card 17. When a record 
start switch provided in the operation unit 21 is operated so that the 
image area is not to be changed, Step 211 is executed, in which the part 
of the image signal, corresponding to the image area, is recorded in the 
memory card 17, using the most recently set compression ratio "R". 
Conversely, when the image area is to be changed, Step 209 is executed, in 
which a cursor (shown as 25 in FIG. 5), for example, indicated on the 
surface of the image indicating device 18, is moved to set a new frame or 
new image area. When the frame is moved, the aspect ratio remains 
constant. The cursor 25 can be moved by operating an arrow key included in 
a keyboard provided in the operation unit 21. Namely, by operating the 
keyboard, the cursor is moved so that the frame is repositioned on the 
surface of the image indicating device 18 while retaining the aspect 
ratio. 
In Step 210, it is determined whether a recording operation is to be 
carried out, i.e. whether the image signal, corresponding to the image 
area selected in Step 209, is to be recorded in the memory card 17. When 
the record start switch is operated, so that the recording operation is 
performed, the process goes to Step 211, and when the start switch is not 
operated, indicating the recording operation is unnecessary, the process 
goes to Step 212. 
In Step 212, it is determined whether the image area is to be set again, 
based on an operation of a setting switch provided in the operation unit 
21. When the image area is to be set again, the process returns to Step 
202, so that the compression ratio "R" is reset to the initial value, and 
then the processes described above are re-executed. Conversely, if it is 
determined in Step 212 that the image area need not be set again, the 
recording operation is not carried out, and this program ends. 
Note that an additional Step, in which it is determined whether Step 211 
should be executed, may be provided between Steps 203 and 211. According 
to the additional Step, when Step 211 should be executed, the process goes 
to Step 211, and when Step 211 should not be executed, the process goes to 
Step 204. 
As described above, according to the embodiment, when the remaining amount 
"F" of the memory card 17 is not large enough to record a single image, 
only a part of the image signal, which corresponds to the frame indicated 
in Step 204 or 208, is recorded in the memory card 17, with the image 
signal being compressed, if necessary. Therefore, even if the remaining 
amount "F" of the memory card 17 is insufficient to record the complete 
image signal, which is not compressed, the image signal can be recorded in 
the memory card 17 to some extent, whereby the usage efficiency of the 
memory card 17 is greatly improved. 
FIG. 3 is a flowchart of a subroutine by which the remaining amount "F" of 
the memory card 17 is divided. This subroutine can be executed in Step 
201. In this case, the contents of Step 201 are changed to "Remaining 
amount dividing routine is executed." 
In Step 301, the remaining amount "F" of the memory card 17, which is 
recordable, is detected, and is indicated on the surface of the image 
indicating device 18 or the display unit 22. In Step 302, a division 
number "K", by which the remaining amount "F" is uniformly divided, is 
inputted due to an operation of the switch provided in the operation unit 
21. In Step 303, by dividing the remaining amount "F" by the division 
number "K", a recording capacity "G", assigned to a single image, is 
calculated and indicated on the surface of the image indicating device 18. 
In Step 304, it is determined whether the value of the division number "K" 
is to be changed, based on an operation of an alteration switch provided 
in the operation unit 21. When the division number "K" should be altered, 
the process returns to Step 302, and when the division number "K" is to 
remain unchanged, Step 305 is executed, in which the remaining amount "F" 
is replaced by the recording capacity "G", calculated in Step 303. Thus, 
this subroutine ends. 
Accordingly, by executing the subroutine in Step 201 of the flowchart shown 
in FIG. 2, the remaining amount "F" of the memory card 17 is uniformly 
divided, so that a plurality of images can be recorded in a plurality of 
uniform recording areas of the memory card 17, respectively. Further, by 
executing Step 206 of the flowchart shown in FIG. 2, in association with 
the subroutine in Step 201, each of the image signals can be recorded in 
the memory card 17, while being optimumly compressed, so that the number 
of images, which are recordable, can be increased. Furthermore, by 
executing Step 209 of the flowchart shown in FIG. 2, an arbitrary image 
area, included in a single image, can be recorded in the memory card 17, 
enabling an unnecessary part of the image to be omitted. 
FIG. 4 is a second example of a flowchart of the program, by which an image 
signal is recorded in the memory card 17. A point different from the first 
example, shown in FIG. 2, is Step 403, the other Steps being the same. In 
Step 403, it is determined whether the compressed-image recording capacity 
((V/R).times.N), wherein "N" is a positive integer, necessary for 
recording image signals, which correspond to N number of images and are 
compressed with the compression ratio "R", is greater than or equal to the 
remaining amount "F" of the memory card 17. When the compressed-image 
recording capacity ((V/R).times.N) is less than the remaining amount "F", 
Step 211 is executed, and when the compressed-image recording capacity 
((V/R).times.N) is greater than or equal to the remaining amount "F", Step 
204 is executed. Note that "N" is set by an operation of the setting 
switch provided in the operation unit 21. 
According to the recording operation shown in FIG. 4, even if the remaining 
amount "F" is less than the compressed-image recording capacity, which is 
necessary for recording the complete image signals compressed with the 
compression ratio "R", a part of each of (N+.alpha.) number of images, 
.alpha. being a positive integer, can be recorded in the memory card 17, 
respectively. Thus, an increase in efficient usage of the recording medium 
is realized. 
Although the embodiments of the present invention have been described 
herein with reference to the accompanying drawings, obviously many 
modifications and changes may be made by those skilled in this art without 
departing from the scope of the invention. 
The present disclosure relates to subject matter contained in Japanese 
Patent Application No. 9-108154 (filed on Apr. 10, 1997) which is 
expressly incorporated herein, by reference, in its entirety.