JP5383349B2 - Image data transfer device - Google Patents

Description

The present invention relates to an image data transfer equipment for transferring image data.

  In recent years, high resolution and high speed have become important for image data of digital cameras and the like. As a method for transferring image data, there is a method using an LVDS (Low Voltage Differential Signaling) serial interface, as shown in Patent Document 1.

  FIG. 7 is a block diagram showing a configuration of an imaging apparatus equipped with a conventional LVDS serial interface. Here, a photographing apparatus such as a camera is taken as an example of image data transmission. The system block 1200 performs image processing and control in a photographing apparatus such as a camera, and includes a signal processing unit 1204, a photographing mode setting unit 1205, a sensitivity setting unit 1206, an exposure amount setting unit 1207, an aperture control unit 1208, and an LVDS receiver. 1209.

  The imaging block 1201 includes an imaging device 1210, an A / D conversion block 1211, a parallel / serial conversion block 1212, and an LVDS driver 1213.

  The lens 1202 collects external light on an image sensor 1210 described later. The aperture 1203 sets the external light to an appropriate exposure amount.

  The signal processing unit 1204 processes internal signals of the system block 1200. A shooting mode setting unit 1205 sets shooting modes such as still images and moving images. The sensitivity setting unit 1206 sets the light sensitivity level. The exposure amount setting unit 1207 sets the amount of light incident on the image sensor 1210 to an optimum value. The aperture control unit 1208 receives information from the exposure amount setting unit 1207 via the signal processing unit 1204, and controls the aperture 1203 so that the amount of light becomes an optimum value. The LVDS receiver 1209 receives serial image data.

  The image sensor 1210 converts the light collected by the lens 1202 into an electrical signal. The A / D conversion block 1211 converts the analog electric signal obtained from the image sensor 1210 into a digital signal. The parallel / serial conversion block 1212 converts the digital parallel signal converted by the A / D conversion block 1211 into serial data. The LVDS driver 1213 transfers the serial data converted by the parallel / serial conversion block 1212 to the LVDS receiver 1209.

  In the imaging apparatus having such a configuration, when increasing the resolution of data for one pixel, as shown in FIG. 8, the number of bits transferred per same time regardless of various modes and shooting conditions. Is increased uniformly. FIG. 8 is a diagram showing a conventional data transfer method. If the data of one pixel is transferred at 20 nS, the imaging apparatus sets the communication rate of 500 Mbps when the resolution is 10 bits, and sets the communication rate of 600 Mbps when the resolution is 12 bits. Speeding up.

  FIG. 9 is a block diagram showing a configuration of an imaging apparatus equipped with a parallel interface. In addition, the same number is attached | subjected about the component similar to FIG. 7, and the description is abbreviate | omitted. The system block 1200 is provided with a data signal receiver 1601. The imaging block 1201 is provided with a data signal driver 1602.

  In the imaging apparatus having such a configuration, when the resolution of data for one pixel is increased, a method of increasing the number of data terminals for connecting the data signal receiver 1601 and the data signal driver 1602 as shown in FIG. It was general.

JP 2005-167760 A

  However, the conventional image data transfer apparatus has the following problems. When the transfer speed is increased in a serial interface or the like, there are problems that the current consumption of the internal output circuit increases and the radiation noise of the transmission line becomes severe.

  Also in the case of the parallel interface, there is a problem that the number of signal lines increases as the number of bits increases, leading to an increase in area.

Accordingly, the present invention, even when the transfer speed is slow, and its object is to be able to transfer image data of high resolution.

Or one of the image data transfer apparatus according to the present invention performs image data generation means for generating image data for one pixel, and transfer means for transferring the image data, the gain-up processing on the image data And determining means for determining whether or not to perform gain-up processing on the image data, the transfer means determines the lower order determined based on the gain amount of the image data. The bit portion is transferred, and a portion other than the lower bit portion determined based on the gain amount is not transferred .

One of the image data transfer apparatuses according to the present invention includes an image data generation unit that generates image data for one pixel, a transfer unit that transfers the image data, and whether or not the image data has low luminance. First determining means for determining, and second determining means for determining whether or not the upper bit portion of the image data is the same as the upper bit portion of the image data transferred before the image data. When the image data has low brightness, and the upper bit portion of the image data is the same as the upper bit portion of the image data transferred before the image data, the transfer means includes the image data The lower bit portion is transferred, and the upper bit portion of the image data is not transferred .

According to the present invention, high-resolution image data can be transferred even when the transfer speed is low .

It is a block diagram which shows the structure of the imaging device in 1st Embodiment. It is a flowchart which shows an image data transfer procedure. It is a figure which shows a data transfer system. It is a block diagram which shows the structure of the imaging device in 2nd Embodiment. It is a flowchart which shows an image data transfer procedure. It is a block diagram which shows the structure of the imaging device in 3rd Embodiment. It is a block diagram which shows the structure of the imaging device carrying the conventional LVDS serial interface. It is a figure which shows the conventional data transfer system. It is a block diagram which shows the structure of the imaging device carrying a parallel interface.

  Embodiments of an image data transfer apparatus and an image data transfer method of the present invention will be described with reference to the drawings. The image data transfer device of this embodiment is applied to an imaging device.

[First Embodiment]
FIG. 1 is a block diagram illustrating a configuration of an imaging apparatus according to the first embodiment. In the first embodiment, data transmission is performed using a serial interface.

  The system block 200 performs image processing and control in a photographing apparatus such as a camera. The system block 200 includes a signal processing unit 204, a shooting mode setting unit (Mode) 205, a sensitivity setting unit (ISO) 206, an exposure amount setting unit (AE) 207, an aperture control unit (Iris) 208, and an LVDS receiver 209.

  The imaging block 201 includes an imaging device 210, an A / D conversion block 211, a parallel / serial conversion block 212, an LVDS driver 213, a memory 214, and a comparator 215.

  The lens 202 collects external light on the image sensor 210. The diaphragm 203 sets the external light to an appropriate exposure amount.

  The signal processing unit 204 processes an internal signal of the system block 200. A shooting mode setting unit 205 sets shooting modes such as a still image shooting mode and a moving image shooting mode. The sensitivity setting unit 206 sets the light sensitivity level. The exposure amount setting unit 207 sets the amount of light incident on the image sensor 210 to an optimum value. The aperture control unit 208 receives information from the exposure amount setting unit 207 via the signal processing unit 204 and controls the aperture 203 so that the amount of light becomes an optimum value. The LVDS receiver 209 receives serial image data.

  The image sensor 210 converts the light collected by the lens 202 into an electrical signal. The A / D conversion block 211 converts the analog electric signal obtained from the image sensor 210 into a digital signal. The parallel / serial conversion block 212 converts the digital parallel signal converted by the A / D conversion block 211 into serial data. The LVDS driver 213 transfers the serial data converted by the parallel / serial conversion block 212 to the LVDS receiver 209. The memory 214 records the upper bits of the parallel data (image data) from the A / D conversion block 211. The comparator 215 compares the high-order bit data stored in the memory 214 with the high-order bits of the parallel data output from the A / D conversion block 211.

  An image data transfer operation of the imaging apparatus having the above configuration will be described. FIG. 2 is a flowchart showing an image data transfer procedure. When transmitting image data, the imaging device detects (detects) a shooting mode based on information from the shooting mode setting unit 205 (step S1). Since still images require high-resolution data, in the present embodiment, it is assumed that 12-bit gradation is necessary. On the other hand, in a moving image or the like for which high resolution is not required compared to a still image, there is no problem even if the gradation is lowered. In this embodiment, it is assumed that a 10-bit gradation is sufficient.

  Therefore, if the image is a moving image when the shooting mode is detected, the imaging device switches the number of bits so that only the upper 10 bits are sent by transmitting mode information from the signal processing unit 204 to the imaging block 201. Only the upper 10 bits are transferred (step S2). As described above, the process of step S2 in which only the upper bits are transferred while ignoring the lower bits is an example of a switching unit. Thereby, in the data transfer at the time of a moving image, 10 bits are sufficient, and the transfer speed can be reduced as compared with the case of sending with 12 bits. Therefore, current consumption of the circuit and radiation noise of the transmission line can be suppressed. Thereafter, the imaging apparatus ends this process.

On the other hand, when the shooting mode is a still image in step S1, the imaging apparatus detects sensitivity setting information from the sensitivity setting unit 206 (step S3). The processing in step S3 is an example of sensitivity information detection means. Based on this sensitivity setting information, the imaging apparatus detects whether or not the digital gain is increased with high sensitivity (step S4). Here, the high sensitivity mode refers to a case where the digital gain is increased by bit shift, and in this case, the upper bits are not necessary .

  When performing digital gain increase in step S4, the imaging apparatus transfers only necessary lower bits in accordance with the gain amount (step S5). For example, when the gain is four times, since the upper 2 bits are unnecessary data, the imaging apparatus transfers only the lower 10 bits. When the gain is 8 times, since the upper 3 bits are unnecessary data, only the lower 9 bits are transferred. Thereby, in the data transfer at the time of high sensitivity, the number of bits can be reduced, and the transfer speed can be reduced as compared with the case of sending with 12 bits. Therefore, current consumption of the circuit and radiation noise of the transmission line can be suppressed. Thereafter, the imaging apparatus ends this process.

  On the other hand, when the digital gain is not increased in step S4, the imaging device detects the exposure amount (step S6). Then, the imaging apparatus determines whether or not the brightness is low based on the information from the exposure amount setting unit 207 (step S7). The process in step S7 is an example of a luminance determination unit. When the brightness is low, there is often little information on the high brightness level, and the imaging apparatus switches the number of bits so that only the lower 10 bits are transmitted while ignoring the upper bits.

  Further, the imaging apparatus uses the comparator 215 to compare the upper bit converted by the A / D conversion block 211 and the upper bit of the previous data stored in the memory 214 (step S8). ) And the presence or absence of the change is determined (step S9). If there is no change, the imaging device transfers only the lower bits (step S10). Thereafter, the imaging apparatus ends this process.

  On the other hand, when there is a change in step S9, the imaging apparatus transfers the lower bit (step S11) and then additionally transfers the higher bit having changed (step S12). Then, the imaging apparatus synthesizes the upper bit and lower bit data in the signal processing unit 204 (step S13). Thereafter, the imaging apparatus ends this process.

  FIG. 3 is a diagram showing a data transfer method. When only the lower bits are transferred in step S10 described above, the transfer time of one pixel data is 20 nS. On the other hand, when the lower bit is transferred in step S11 and then the upper bit is transferred in step S12, the transfer time of one pixel data is 24 nS.

  On the other hand, when it is determined in step S7 that the brightness is not low, the imaging apparatus transfers all bits only in this case (step S14). Thereafter, the imaging apparatus ends this process.

  As described above, when the 12-bit resolution is required, the image pickup apparatus according to the first embodiment obtains high-resolution image data by transferring all bits, as well as image data according to each shooting mode, shooting conditions, and the like. Only the necessary upper and lower bits are transferred according to the state.

  That is, the imaging device determines the required bits based on the state of the image data, switches the number of bits of the image data to be transferred based on the result of the determination, and the image data having the switched number of bits. Forward. Thus, high-resolution image data can be transferred even at a low communication rate. Therefore, when transferring image data, it is not necessary to increase the transfer speed, and the current consumption of the circuit and the radiation noise of the transmission line can be suppressed.

  Also, since the required bits are determined according to the shooting mode, high-resolution image data such as still images can be transferred with a reduced number of bits, and images with low gradation such as moving images can be transferred. Data can be transferred with a small number of bits. Also, since only the lower bits are transferred, it is effective when transferring image data of a low-luminance still image. Further, since only the upper bits are transferred, it is effective when transferring image data with low gradation such as a moving image.

  Further, the number of bits to be transferred can be reduced according to the sensitivity setting. Also, the greater the amount of increase in digital gain, the smaller the number of bits transferred. In addition, since the upper bits are transferred only when there is a change in the upper bits, the number of times of transferring both the upper bits and the lower bits can be reduced.

  Also, since image data is transferred by serial communication, current consumption of the internal output circuit and radiation noise of the transmission line can be suppressed without increasing the transfer speed in the serial interface even if the resolution of the image data is increased. .

  In this embodiment, as an example, in the case of 12-bit resolution, transfer of upper 10 bits or lower 10 bits is selected, but it is important to transfer with a smaller number of bits than the maximum necessary number of bits. Therefore, there is no particular restriction on the number of bits.

[Second Embodiment]
When the brightness is low, there are many dark images, and the upper bits are often “0”. For this reason, there is little change in the upper bits, and the image data transfer method of the first embodiment is effective. However, when there are many changes in the upper bits, the number of times of transmitting the upper bits increases. Therefore, the second embodiment corresponds to such a case.

  FIG. 4 is a block diagram illustrating a configuration of the imaging apparatus according to the second embodiment. Here, the same portions as those in FIG. 1 of the first embodiment are denoted by the same reference numerals, and the description thereof is omitted. In the imaging apparatus according to the second embodiment, unlike the first embodiment, a mode value calculation block 801 is provided in the system block 200.

  FIG. 5 is a flowchart showing an image data transfer procedure. The same step numbers as those in FIG. 2 of the first embodiment are denoted by the same step numbers, and the description thereof is omitted.

  If the digital gain is not increased in step S4, the imaging apparatus sets the exposure amount using the exposure amount setting unit 207 (step S6A). Here, in order to perform exposure amount setting by the exposure amount setting unit 207, it is necessary to acquire image data in advance. The process of acquiring image data in advance when setting the exposure amount is an example of an image information acquisition unit.

  The imaging apparatus uses the mode data obtained in advance, and uses the mode value calculation block 801 to calculate the mode value of the upper bits (step S7A). Then, the imaging apparatus stores the calculated mode value in the memory 214.

  The imaging apparatus compares the information recorded in the memory 214 (mode value of the upper bits) with the upper bits of the image data converted by the A / D conversion block 211 (step S8), and determines whether there is a change. (Step S9). If there is a difference in change in step S9, that is, if there is a difference in upper bits, the imaging device first transfers the lower bits (step S11), and further adds the upper bits that have changed. (Step S12). Then, the imaging device finally combines the upper bit and the lower bit to form image data (step S13).

  On the other hand, if there is no difference in change in step S9, the imaging apparatus transfers only the lower bits without transferring the upper bit data (step S10). Then, the imaging apparatus combines the mode value calculated in the mode value calculation block 801 and the lower bits transferred in step S10 to form image data (step S10A).

  As described above, the imaging apparatus according to the second embodiment transmits only data different from the mode value without transmitting the mode value data. For example, when the bits to be recorded are the upper 2 bits, it is not necessary to transmit the upper bits, which are at least 1/4 of the image data.

  As a result, compared to the case where all data is transmitted in 12 bits, the information to be transmitted is reduced, and 12-bit data is transmitted even at a low transfer rate.

  Also, by sending only the data different from the mode value without sending the mode value data, the information to be transmitted is reduced compared to the case of sending all bit data, and even if the transfer rate is slow, all bits Can send data. Further, since the image information is image data acquired for setting the exposure amount, image data acquired in advance can be used.

  In the present embodiment, as in the first embodiment, as an example, in the case of 12-bit resolution, transfer of upper 10 bits or lower 10 bits is selected. However, since it is important to transfer with a small number of bits with respect to the maximum necessary number of bits, there is no particular restriction on the number of bits.

[Third Embodiment]
The third embodiment shows a case where data transfer is performed using a parallel interface. FIG. 6 is a block diagram illustrating a configuration of an imaging apparatus according to the third embodiment. Here, the same portions as those in FIG. 1 of the first embodiment are denoted by the same reference numerals, and the description thereof is omitted. Unlike the serial communication of the first embodiment, the imaging apparatus of the third embodiment performs parallel communication.

  In the system block 200 of the third embodiment, a data signal receiver 901 is provided instead of the LVDS receiver. The imaging block 201 is provided with a data signal driver 902 and a changeover switch 903 instead of the parallel / serial conversion block 212 and the LVDS driver 213.

  If the resolution of one pixel is 12 bits at the maximum, 12 data buses are usually drawn (connected) for data transfer between the system block 200 and the imaging block 201. In the present embodiment, for example, 10 Data transfer can be performed using the data bus.

  As in the first embodiment, the comparator 215 compares the upper bits stored in the memory 214 with the upper bits of the parallel data output from the A / D conversion block 211.

  The data signal receiver 901 and the data signal driver 902 transmit / receive 10-bit data. The changeover switch 903 switches necessary bits in accordance with the signal from the comparator 215 and the mode information from the signal processing unit 204.

  A data transfer operation of the imaging apparatus according to the third embodiment having such a configuration will be described. The data transfer procedure is almost the same as the procedure shown in FIG. 2 of the first embodiment. When it is determined that the shooting mode is a moving image (step S1 in FIG. 2), the imaging apparatus switches the bits required by the changeover switch 903 and sets the upper 10 bits between the data signal receiver 901 and the data signal driver 902. Transmission / reception is performed (step S2 in FIG. 2).

  Even when the sensitivity setting information is detected (step S3 in FIG. 2), the imaging apparatus switches the bits required by the changeover switch 903, and the lower 10 between the data signal receiver 901 and the data signal driver 902. Send and receive bits.

  Further, in the case of a still image, only when all 12 bits are transmitted (steps S11, S12, and S14 in FIG. 2), the imaging apparatus first selects the lower 10 bits with the changeover switch 903, and the data signal receiver 901 and the data signal Data is transmitted to and received from the driver 902. Next, the imaging apparatus selects the remaining 2 bits with the changeover switch 903 and transmits / receives data between the data signal receiver 901 and the data signal driver 902.

  According to the imaging apparatus of the third embodiment, when sending 12 bits, the transmission speed is slow because it is sent twice, but only when there is a change in the upper bits or when the brightness is high. As a result, the transmission speed is faster than when 12-bit data is continuously sent. Therefore, high-resolution data can be sent without increasing the transfer speed.

  In addition, since image data is transferred by parallel communication, it is possible to suppress an increase in signal lines and an increase in area in a parallel interface.

  In the third embodiment, as in the first embodiment, it is possible to store the upper bits in the memory 214 based on the luminance information.

  Also in the third embodiment, as in the second embodiment, in order to set the exposure amount, image data is acquired in advance, and the imaging apparatus acquires the image data acquired in advance. It is also possible to calculate the mode value of the upper bits in the mode value calculation block and perform the same processing.

  As in the first and second embodiments, as an example, in the case of 12-bit resolution, transfer of upper 10 bits or lower 10 bits is selected. However, since it is important to transfer with a small number of bits with respect to the maximum necessary number of bits, there is no particular restriction on the number of bits.

  The present invention is not limited to the configuration of the above-described embodiment, and any configuration can be used as long as the functions shown in the claims or the functions of the configuration of the present embodiment can be achieved. Is also applicable.

  For example, in the above-described embodiment, a case where the present invention is applied to an imaging device that generates image data has been described. However, the present invention is not particularly limited as long as it is a device that transfers image data. It is also applicable to.

  In addition, the present invention may be applied to an apparatus that transfers image data within one apparatus, or may be applied to an apparatus that transfers image data between apparatuses in a system composed of a plurality of apparatuses.

200 System Block 201 Imaging Block 204 Signal Processing Unit 205 Shooting Mode Setting Unit 206 Sensitivity Setting Unit 209 LVDS Receiver 211 A / D Conversion Block 212 Parallel / Serial Conversion Block 213 LVDS Driver

Claims (19)

Image data generating means for generating image data for one pixel;
Transfer means for transferring the image data;
Has <br/> and determining means for determining whether to perform the gain-up processing for the image data,
When it is determined to perform gain-up processing on the image data, the transfer unit transfers a lower bit portion determined based on the gain amount in the image data, and based on the gain amount images data transfer device you characterized in that the portion other than the determined lower bit portion so as not to transfer. A determination means for determining whether or not the image data has low brightness when it is determined not to perform gain-up processing on the image data;
2. The image data transfer apparatus according to claim 1, wherein, when the image data is not low luminance, the transfer means transfers the upper bit portion of the image data and the lower bit portion of the image data. First determination means for determining whether or not the image data has low brightness when it is determined not to perform gain-up processing on the image data;
Second determining means for determining whether or not the upper bit portion of the image data is the same as the upper bit portion of the image data transferred before the image data;
When the image data has low luminance, if the upper bit portion of the image data is the same as the upper bit portion of the image data transferred before the image data, the transfer means 2. The image data transfer apparatus according to claim 1, wherein a bit part is transferred and an upper bit part of the image data is not transferred. When the image data has low luminance, if the upper bit portion of the image data is not the same as the upper bit portion of the image data transferred before the image data, the transfer means 4. The image data transfer apparatus according to claim 3, wherein the portion and the lower bit portion of the image data are transferred. First determination means for determining whether or not the image data has low brightness when it is determined not to perform gain-up processing on the image data;
Second determining means for determining whether or not the upper bit part of the image data is different from the upper bit part of the image data transferred before the image data;
When the image data has low luminance, if the upper bit portion of the image data is different from the upper bit portion of the image data transferred before the image data, the transfer means is configured to transfer the upper bit portion of the image data. 2. The image data transfer apparatus according to claim 1, wherein a lower bit portion of the image data is transferred. Having an imaging device for imaging,
The image data transfer device according to claim 1, wherein the image data generation unit generates the image data based on a signal from the imaging element. When the shooting mode of the image data transfer device is a mode for shooting a moving image, the transfer means transfers the upper bit portion of the image data and does not transfer the lower bit portion of the image data. The image data transfer apparatus according to claim 1, wherein the image data transfer apparatus is an image data transfer apparatus. 2. The determination as to whether or not to perform gain-up processing on the image data is performed when a shooting mode of the image data transfer apparatus is a mode for shooting a still image. 8. The image data transfer device according to any one of items 1 to 7. Said transfer means, the image data transfer device according part or all in any one of claims 1 to 8, characterized in that to transfer the serial data before the SL image data. It said transfer means, the image data transfer device according to any one of claims 1 8, characterized in that to transfer part or all of the pre-Symbol image data as parallel data. Image data generating means for generating image data for one pixel;
Transfer means for transferring the image data;
First determination means for determining whether or not the image data has low luminance;
Second determination means for determining whether or not the upper bit portion of the image data is the same as the upper bit portion of the image data transferred before the image data;
Have
When the image data has low luminance, if the upper bit portion of the image data is the same as the upper bit portion of the image data transferred before the image data, the transfer means An image data transfer apparatus, wherein a bit part is transferred and an upper bit part of the image data is not transferred. When the image data has low luminance, if the upper bit portion of the image data is not the same as the upper bit portion of the image data transferred before the image data, the transfer means is configured to transfer the lower bit of the image data. 12. The image data transfer apparatus according to claim 11, wherein the portion and the upper bit portion of the image data are transferred. 13. The image data transfer device according to claim 11 or 12, wherein, when the image data is not low-luminance, the transfer means transfers an upper bit part of the image data and a lower bit part of the image data. . Having an imaging device for imaging,
The image data transfer device according to claim 11, wherein the image data generation unit generates the image data based on a signal from the imaging element. When the shooting mode of the image data transfer device is a mode for shooting a moving image, the transfer means transfers the upper bit portion of the image data and does not transfer the lower bit portion of the image data. The image data transfer apparatus according to claim 11, wherein the image data transfer apparatus is an image data transfer apparatus. 16. The determination as to whether or not the image data has a low luminance is performed when a shooting mode of the image data transfer apparatus is a mode for shooting a still image. The image data transfer device according to any one of the above. Determining means for determining whether to perform gain-up processing on the image data;
The determination as to whether or not the image data has low luminance is made when it is determined not to perform gain-up processing on the image data. The image data transfer device according to Item. 18. The image data transfer apparatus according to claim 11, wherein the transfer unit transfers part or all of the image data as serial data. 18. The image data transfer apparatus according to claim 11, wherein the transfer unit transfers part or all of the image data as parallel data.